Prioritize user privacy and data security in your app. Discuss best practices for data handling, user consent, and security measures to protect user information.

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com.apple.developer.web-browser.public-key-credential still leads to com.apple.AuthenticationServices.AuthorizationError Code=1004
Hi, we were recently approved for the com.apple.developer.web-browser.public-key-credential entitlement and have added it to our app. It initially worked as expected for a couple of days, but then it stopped working. We're now seeing the same error as before adding the entitlement: Told not to present authorization sheet: Error Domain=com.apple.AuthenticationServicesCore.AuthorizationError Code=1 "(null)" ASAuthorizationController credential request failed with error: Error Domain=com.apple.AuthenticationServices.AuthorizationError Code=1004 "(null)" Do you have any insights into what might be causing this issue? Thank you!
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Mar ’26
PCC VRE: 403 Forbidden when downloading SW Release 41303
Is anyone else seeing 403 errors for PCC VRE when trying to pull assets for Release 41303? My pccvre audit of the Transparency Log passes (valid root digests for 41385), but the download fails consistently on specific CDN URLs: Failed to download SW release asset... response: 403 I’ve verified csrutil allow-research-guests is active and the license is accepted. Release 41385 seems fine, but 41303 is a brick wall. Is this a known pull-back or a CDN permissions sync issue?
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https://app-site-association.cdn-apple.com/a/v1/* 404 Not Found
% curl -v https://app-site-association.cdn-apple.com/a/v1/zfcs.bankts.cn Host app-site-association.cdn-apple.com:443 was resolved. IPv6: (none) IPv4: 218.92.226.151, 119.101.148.193, 218.92.226.6, 115.152.217.3 Trying 218.92.226.151:443... Connected to app-site-association.cdn-apple.com (218.92.226.151) port 443 ALPN: curl offers h2,http/1.1 (304) (OUT), TLS handshake, Client hello (1): CAfile: /etc/ssl/cert.pem CApath: none (304) (IN), TLS handshake, Server hello (2): (304) (IN), TLS handshake, Unknown (8): (304) (IN), TLS handshake, Certificate (11): (304) (IN), TLS handshake, CERT verify (15): (304) (IN), TLS handshake, Finished (20): (304) (OUT), TLS handshake, Finished (20): SSL connection using TLSv1.3 / AEAD-AES256-GCM-SHA384 / [blank] / UNDEF ALPN: server accepted http/1.1 Server certificate: subject: C=US; ST=California; O=Apple Inc.; CN=app-site-association.cdn-apple.com start date: Sep 25 13:58:08 2025 GMT expire date: Mar 31 17:44:25 2026 GMT subjectAltName: host "app-site-association.cdn-apple.com" matched cert's "app-site-association.cdn-apple.com" issuer: CN=Apple Public Server RSA CA 11 - G1; O=Apple Inc.; ST=California; C=US SSL certificate verify ok. using HTTP/1.x GET /a/v1/zfcs.bankts.cn HTTP/1.1 Host: app-site-association.cdn-apple.com User-Agent: curl/8.7.1 Accept: / Request completely sent off < HTTP/1.1 404 Not Found < Content-Type: text/plain; charset=utf-8 < Content-Length: 10 < Connection: keep-alive < Server: nginx < Date: Wed, 04 Feb 2026 02:26:00 GMT < Expires: Wed, 04 Feb 2026 02:26:10 GMT < Age: 24 < Apple-Failure-Details: {"cause":"context deadline exceeded (Client.Timeout exceeded while awaiting headers)"} < Apple-Failure-Reason: SWCERR00301 Timeout < Apple-From: https://zfcs.bankts.cn/.well-known/apple-app-site-association < Apple-Try-Direct: true < Vary: Accept-Encoding < Via: https/1.1 jptyo12-3p-pst-003.ts.apple.com (acdn/3.16363), http/1.1 jptyo12-3p-pac-043.ts.apple.com (acdn/3.16363), https/1.1 jptyo12-3p-pfe-002.ts.apple.com (acdn/3.16363) < X-Cache: MISS KS-CLOUD < CDNUUID: 736dc646-57fb-43c9-aa0d-eedad3a534f8-1154605242 < x-link-via: yancmp83:443;xmmp02:443;fzct321:443; < x-b2f-cs-cache: no-cache < X-Cache-Status: MISS from KS-CLOUD-FZ-CT-321-35 < X-Cache-Status: MISS from KS-CLOUD-XM-MP-02-16 < X-Cache-Status: MISS from KS-CLOUD-YANC-MP-83-15 < X-KSC-Request-ID: c4a640c815640ee93c263a357ee919d6 < CDN-Server: KSFTF < X-Cdn-Request-ID: c4a640c815640ee93c263a357ee919d6 < Not Found Connection #0 to host app-site-association.cdn-apple.com left intact
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Feb ’26
Local network permission
Hi everyone, We are working on an app that requires access to devices on the local network (Bonjour / LAN discovery + direct socket communication). We are currently struggling with the Local Network privacy permission flow introduced by Apple. From our understanding, there is no dedicated public API to explicitly request Local Network permission or to reliably determine the current authorization state before attempting network activity. We have tried several commonly suggested approaches to trigger the permission dialog, including: Bonjour browsing via NWBrowser Publishing/listening with NetService UDP/TCP socket attempts on local subnet NWConnection / NWListener Triggering discovery after app launch and after foreground transitions We already added the required entries in: NSLocalNetworkUsageDescription NSBonjourServices However, the behavior is inconsistent across devices and OS versions: Sometimes the popup appears immediately Sometimes it never appears Sometimes network operations silently fail without callback clarity In some cases callbacks are delayed or ambiguous Reinstalling/resetting permissions changes behavior unpredictably Our main challenges are: What is currently considered the most reliable Apple-approved method to trigger the Local Network permission prompt? Is there any officially recommended way to determine whether permission is: not determined denied granted Is there any reliable callback or state transition API developers should use? Are there known differences between: NWBrowser NetService BSD sockets NWConnection when it comes to triggering the permission dialog? Are there recommended retry/timing patterns to avoid race conditions during app launch? Is Apple planning to introduce a dedicated authorization API similar to: AVAuthorizationStatus CLAuthorizationStatus PHPhotoLibrary.authorizationStatus() Right now it feels difficult to provide a reliable UX because there is no deterministic way to: proactively request access observe authorization state recover gracefully when the prompt does not appear Any guidance, DTS references, WWDC sessions, or recommended implementation patterns would be greatly appreciated. Thanks!
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How to use App Attest Environment?
Hi, I'm looking at adding App Attest to an app, and I think I understand the mechanics of the attestation process, but I'm having trouble figuring out how development and testing are supposed to work. Two main questions: The "App Attest Environment" -- the documentation says that attestation requests made in the .development sandbox environment don't affect the app's risk metrics, but I'm not sure how to actually use this sandbox. My understanding is that one of the things App Attest does is to ensure that your app has been appropriately signed by the App Store, so it knows that it hasn't been tampered with. But the docs say that App Store builds (and Test Flight and Developer Enterprise Program) always use the .production environment. Does App Attest actually work for local developer-build apps if you have this entitlement set? Presumably only on hardware devices since it requires the Secure Enclave? Does our headend have to do something different when verifying the public key and subsequent attested requests for an app that's using the .development sandbox? The docs do mention that a headend server should potentially track two keys per device/user pair so that it can have a production and development key. How does the headend know if a key is from the sandbox environment? Thanks!
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Jun ’25
passkey in iOS via iCloudKeyChain
I have a very basic binary question around passkeys. Assuming everything is on latest and greatest version with respect to iOS, when user starts creating a passkey in platform-authenticator i.e., iCloudKeyChain (Apple Password Manager) , will iCloudKeyChain create a hardware-bound passkey in secure-enclave i.e., is brand new key-pair created right inside Secure-enclave ? OR will the keypair be created in software i.e., software-bound-passkey ?? i.e., software-bound keypair and store the private-key locally in the device encrypted with a key that is of course created in secure-enclave.
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May ’25
Platform SSO: Biometric Prompt Behavior with userSecureEnclaveKey
I have a question regarding Platform SSO and the use of Secure Enclave–backed keys with biometric policies. If we configure userSecureEnclaveKeyBiometricPolicy with userSecureEnclaveKey, my understanding is that the Secure Enclave key is protected by biometric authentication (e.g., Face ID / Touch ID). In this setup, during a login request that also refreshes the id_token and refresh_token, the assertion is signed using the userSecureEnclaveKey. My question is: Will this signing operation trigger a biometric prompt every time the assertion is generated (i.e., during login/token refresh) ?
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Mar ’26
App Attest attestationData request fails with 400 Bad Request (no X-Request-ID)
Hello Apple Team We are integrating App Attest with our backend and seeing a 400 Bad Request response when calling the attestation endpoint. The issue is that the response does not include an X-Request-ID or JSON error payload with id and code, which makes it hard to diagnose. Instead, it only returns a receipt blob. Request Details URL: https://data-development.appattest.apple.com/v1/attestationData Request Headers: Authorization: eyJraWQiOiI0RjVLSzRGV1JaIiwidHlwIjoiSldUIiwiYWxnIjoiRVMyNTYifQ.eyJpc3MiOiJOOVNVR1pNNjdRIiwiZXhwIjoxNzU3MDUxNTYwLCJpYXQiOjE3NTcwNDc5NjB9.MEQCIF236MqPCl6Vexg7RcPUMK8XQeACXogldnpuiNnGQnzgAiBQqASdbJ64g58xfWGpbzY3iohvxBSO5U5ZE3l87JjfmQ Content-Type: application/octet-stream Request Body: (Binary data, logged as [B@59fd7d35) Response Status: 400 Bad Request Response Headers: Date: Fri, 05 Sep 2025 04:52:40 GMT x-b3-traceid: 4c42e18094022424 x-b3-spanid: 4c42e18094022424 Response Body (truncated): "receipt": h'308006092A864886F70D01070... Problem The response does not include X-Request-ID. The response does not include JSON with id or code. Only a receipt blob is returned. Questions Can the x-b3-traceid be used by Apple to trace this failed request internally? Is it expected for some failures to return only a receipt blob without X-Request-ID? How should we interpret this error so we can handle it properly in production? Thanks in advance for your guidance.
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Sep ’25
email sent to to an iCloud account is landed to junk when email sent from user-*dev*.company.com micro service
Our company has a micro service which sends a notification email to an iCloud account/email and the email is going to the junk folder. As we tested, the email generated from user-field.company.com goes to the Inbox, while the email from user-dev.company.com goes to the Junk folder. Is there a way to avoid sending the emails to client's Junk folder when the email is sent from a specific company domain?
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Feb ’26
App Review Guidelines 2.5.1 / 2.5.2 — official guidance on screen capture protection for sensitive content
Hi all, We are developing an iOS app that includes private user-to-user chats, commercial offer details with monetary value, and customer identification data. In line with OWASP MASVS-PLATFORM-3 requirements regarding unintentional sensitive data exposure, we need to protect these specific screens from screenshots and screen recording. We have carefully reviewed the relevant App Review Guidelines (2.5.1 on public APIs, 2.5.2 on self-contained bundles, 5.1.1 on privacy) and the related Human Interface Guidelines. From this analysis we have observed the following: iOS does not expose a public API to globally disable screen capture (no direct equivalent of Android's FLAG_SECURE). The SwiftUI .privacySensitive() modifier is effective for Lock Screen widgets and Always-On Display, but it does not appear to prevent screenshots or screen recording of an app's main UI while in the foreground. A number of widely distributed App Store apps (banking, authenticator, secure messaging) implement some form of screenshot protection on sensitive screens. Several established open-source libraries leverage the system behavior of UITextField with isSecureTextEntry as a wrapping container for arbitrary views, in order to achieve pixel-level protection for sensitive content. We would appreciate clarification on the following points: For privacy-driven protection of sensitive screens (private chats, customer data, monetized offers), is there an officially recommended approach we may have missed? Are there public APIs intended specifically for this use case beyond .privacySensitive()? Is the practice of leveraging UITextField with isSecureTextEntry as a wrapping container for arbitrary views considered an acceptable use of public APIs under Guideline 2.5.1, or does it carry App Review risk? Are there official recommendations or documentation for apps handling sensitive personal data that wish to align with industry standards such as OWASP MASVS-PLATFORM-3 for screenshot and screen recording leakage prevention? The intended use is strictly limited to a small number of screens marked as containing sensitive data (private messages, deal details, customer information). The protection would be selective and clearly communicated to the user via in-app messaging, not global to the app. Thanks in advance for any clarification, including pointers to existing documentation or threads we may have missed. Deployment target: iOS 15+
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AASA not being fetched immediately upon app install
Hi Apple Devs, For our app, we utilize passkeys for account creation (not MFA). This is mainly for user privacy, as there is 0 PII associated with passkey account creation, but it additionally also satisfies the 4.8: Login Services requirement for the App Store. However, we're getting blocked in Apple Review. Because the AASA does not get fetched immediately upon app install, the reviewers are not able to create an account immediately via passkeys, and then they reject the build. I'm optimistic I can mitigate the above. But even if we pass Apple Review, this is a pretty catastrophic issue for user security and experience. There are reports that 5% of users cannot create passkeys immediately (https://developer.apple.com/forums/thread/756740). That is a nontrivial amount of users, and this large of an amount distorts how app developers design onboarding and authentication flows towards less secure experiences: App developers are incentivized to not require MFA setup on account creation because requiring it causes significant churn, which is bad for user security. If they continue with it anyways, for mitigation, developers are essentially forced to add in copy into their app saying something along the lines of "We have no ability to force Apple to fetch the config required to continue sign up, so try again in a few minutes, you'll just have to wait." You can't even implement a fallback method. There's no way to check if the AASA is available before launching the ASAuthorizationController so you can't mitigate a portion of users encountering an error!! Any app that wants to use the PRF extension to encrypt core functionality (again, good for user privacy) simply cannot exist because the app simply does not work for an unspecified amount of time for a nontrivial portion of users. It feels like a. Apple should provide a syscall API that we can call to force SWCD to verify the AASA or b. implement a config based on package name for the app store such that the installation will immediately include a verified AASA from Apple's CDN. Flicking the config on would require talking with Apple. If this existed, this entire class of error would go away. It feels pretty shocking that there isn't a mitigation in place for this already given that it incentivizes app developers to pursue strictly less secure and less private authentication practices.
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Aug ’25
LAContext and its usage in context of Local Authentication
While working with Local Authentication framework, specifically LAContext class I found myself with few contradictions to documentation, and although I believe that those differences are rather positive than negative, either documentation is lacking behind or those APIs are not working as intended - which I believe is combination of both. 1. Local Authentication 1.1 Biometry type, and associated with it hash With introduction of LADomainState one can extract underlying biometry type along it's (current) state hash this way: @available(iOS 18, macOS 15, *) func postIOS18() { let context = LAContext() let biometryType = context.domainState.biometry.biometryType // (1) let biometryStateHash = context.domainState.biometry.stateHash // (2) } prior to receiving above APIs, we would retrieve such information something along those lines: func preIOS18() { let context = LAContext() let policy: LAPolicy // ... var error: NSError? _ = context.canEvaluatePolicy(policy, error: error) // (3) // ... (Handle error - if present) let biometryType = context.biometryType // (4) let biometryStateHash = context.evaluatedPolicyDomainState // (5) } However, moving let biometryType = context.biometryType (4) before call to canEvaluatePolicy (3) still yields correct biometry type. This is in contradiction to article from Local Authentication documentation page Optionally, Adjust Your User Interface to Accommodate Face ID. Furthermore, biometryType documentation does not mentions such requirement. Another difference is that call to canEvaluatePolicy (3) might return an error, eg. LAError(.biometryLockout) (if implemented correctly) preventing as from returning biometryStateHash (5) with nil value. This is not the case for new API, where the same call (2) will yield nil as a result - LADomainStateBiometry documentation does not mention it. In summary, here are some questions: Which API should be used to retrieve biometry type?, and why the "older way" has not been deprecated? Is is safe to assume that calls to biometryType and stateHash from LADomainStateBiometry will produce meaningful results without prior call to canEvaluatePolicy? Should I assume that call to biometryType found on LAContext instance will always return biometryType without prior call to canEvaluatePolicy?, or perhaps those are only side effects of changes made to accommodate LADomainState, and prior to them (pre-iOS 18) we must call canEvaluatePolicy to get meaningful value. Are the stateHash properties found on LADomainState, LADomainStateBiometry and LADomainStateCompanion will return nil upon encountering any error under the hood? (which would be equivalent of below code, prior to iOS 18) func biometryStateHash() -> Data? { let context = LAContext() if #available(iOS 18, macOS 15, *) { _ = context.canEvaluatePolicy(policy, error: nil) return context.evaluatedPolicyDomainState } else { return context.domainState.biometry.stateHash } } 1.2 Deprecation of evaluatedDomainState There is a forum post LAContext.evaluatedPolicyDomainState change between major OS versions mentioning missing documentation (fixed), however there's still information missing of how they correlate to each other. From my findings, the deprecated evaluatedDomainState property value matches those of LADomainState stateHash (when no companion device is present), and LADomainStateBiometry stateHash (all the time). Are those assumptions correct? 1.3 LAContext (authenticated) session lifespan Theres is little information about it state when authenticated by the user. Documentation on LAContext does not mention this behavior, while there are hints that once authenticated, and context is reused, any farther calls will not prompt user with UI. The problem is that this behavior is little, to no documented. Here are few examples I have found: Logging a User into Your App with Face ID or Touch ID (code sample) contains comment // Get a fresh context for each login. If you use the same context on multiple attempts //  (by commenting out the next line), then a previously successful authentication //  causes the next policy evaluation to succeed without testing biometry again. //  That's usually not what you want. Recent forum post, where such approach is mentioned by Quinn 'The Eskimo!' "At the API level, one option you have is to create an LAContext and pass it in to each SecItemCopyMatching call via kSecUseAuthenticationContext." WWDC22 Streamline local authorization flows session "By binding the LAContext to our private key reference, we ensure that executing the signature operation will not trigger another authentication, while allowing the operation to continue without unnecessary prompts. These binding also means that no additional user interactions will be required for future signatures until the LAContext is invalidated." Furthermore this is complicated by the touchIDAuthenticationAllowableReuseDuration property from LAContext instance which states that "The default value is 0, meaning that no previous biometric unlock can be reused." which is in direct contradiction to what I have experienced while working with LAContext and sources mentioned above. While digging on this, whether this behavior is intended or not, I came across a post (I would love to share it, but the domain is not permitted) that shared the same findings (and concerns) regarding LAContext behavior as me. The author also provided a FB9984036 feedback number - although no further update was made on that topic. So my questions are: Is it safe to reuse LAContext (authenticated) instance? How long such instance is considered authenticated?, is it a time duration or perhaps it stays in authenticated state until explicitly invalidated using invalidate method. (its invalidated for sure when app is terminated, but this was to be expected :)) How does touchIDAuthenticationAllowableReuseDuration work, and how does it correlate to "reusability" of the authenticated LAContext instance? In what scenarios touchIDAuthenticationAllowableReuseDuration should be used and what is its expected behavior? (I have tried it both on iOS and macOS; from my perspective API this does not "work")
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Password AutoFill does not pick up saved password in developer mode
Without developer mode, I was able to get Password AutoFill to work in my SwiftUI app with my local Vapor server using ngrok and adding the Associated Domains capability with the value webcredentials:....ngrok-free.app and the respective apple-app-site-association file on my local server in /.well-known/. (works on device, but not in the simulator). However, if I use the developer mode (webcredentials:....ngrok-free.app?mode=developer) it only works halfway when running from Xcode: I get asked to save the password, but the saved passwords are not picked up, when I try to login again. Neither on device, nor in the simulator. If I remove the ?mode=developer it seems to work as expected. Is this by design, or am I missing something? var body: some View { ... Section(header: Text("Email")) { TextField("Email", text: $viewModel.credentials.username) .textContentType(.username) .autocapitalization(.none) .keyboardType(.emailAddress) } Section(header: Text("Passwort")) { SecureField("Passwort", text: $viewModel.credentials.password) .textContentType(.password) } ... }
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May ’25
App Groups: macOS vs iOS: Working Towards Harmony
I regularly see folks confused by the difference in behaviour of app groups between macOS and iOS. There have been substantial changes in this space recently. While much of this is now covered in the official docs (r. 92322409), I’ve updated this post to go into all the gory details. If you have questions or comments, start a new thread with the details. Put it in the App & System Services > Core OS topic area and tag it with Code Signing and Entitlements. Oh, and if your question is about app group containers, also include Files and Storage. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" App Groups: macOS vs iOS: Working Towards Harmony There are two styles of app group ID: iOS-style app group IDs start with group., for example, group.eskimo1.test. macOS-style app group IDs start with your Team ID, for example, SKMME9E2Y8.eskimo1.test. This difference has been the source of numerous weird problems over the years. Starting in Feb 2025, iOS-style app group IDs are fully supported on macOS for all product types [1]. If you’re writing new code that uses app groups, use an iOS-style app group ID. If you have existing code that uses a macOS-style app group ID, consider how you might transition to the iOS style. IMPORTANT The Feb 2025 changes aren’t tied to an OS release but rather to a Developer website update. For more on this, see Feb 2025 Changes, below. [1] If your product is a standalone executable, like a daemon or agent, wrap it in an app-like structure, as explained in Signing a daemon with a restricted entitlement. iOS-Style App Group IDs An iOS-style app group ID has the following features: It starts with the group. prefix, for example, group.eskimo1.test. You allocate it on the Developer website. This assigns the app group ID to your team. You then claim access to it by listing it in the App Groups entitlement (com.apple.security.application-groups) entitlement. That claim must be authorised by a provisioning profile [1]. The Developer website will only let you include your team’s app group IDs in your profile. For more background on provisioning profiles, see TN3125 Inside Code Signing: Provisioning Profiles. iOS-style app group IDs originated on iOS with iOS 3.0. They’ve always been supported on iOS’s child platforms (iPadOS, tvOS, visionOS, and watchOS). On the Mac: They’ve been supported by Mac Catalyst since that technology was introduced. Likewise for iOS Apps on Mac. Starting in Feb 2025, they’re supported for other Mac products. [1] Strictly speaking macOS does not require that, but if your claim is not authorised by a profile then you might run into other problems. See Entitlements-Validated Flag, below. macOS-Style App Group IDs A macOS-style app group ID has the following features: It should start with your Team ID [1], for example, SKMME9E2Y8.eskimo1.test. It can’t be explicitly allocated on the Developer website. Code that isn’t sandboxed doesn’t need to claim the app group ID in the App Groups entitlement. [2] To use an app group, claim the app group ID in the App Groups entitlement. The App Groups entitlement is not restricted on macOS, meaning that this claim doesn’t need to be authorised by a provisioning profile [3]. However, if you claim an app group ID that’s not authorised in some way, you might run into problems. More on that later in this post. If you submit an app to the Mac App Store, the submission process checks that your app group IDs make sense, that is, they either start with your Team ID (macOS style) or are assigned to your team (iOS style). [1] This is “should” because, historically, macOS has not actually required it. However, that’s now changing, with things like app group container protection. [2] This was true prior to macOS 15. It may still technically be true in macOS 15 and later, but the most important thing, access to the app group container, requires the entitlement because of app group container protection. [3] Technically it’s a validation-required entitlement, something that we’ll come back to in the Entitlements-Validated Flag section. Feb 2025 Changes On 21 Feb 2025 we rolled out a change to the Developer website that completes the support for iOS-style app group IDs on the Mac. Specifically, it’s now possible to create a Mac provisioning profile that authorises the use of an iOS-style app group ID. Note This change doesn’t affect Mac Catalyst or iOS Apps on Mac, which have always been able to use iOS-style app group IDs on the Mac. Prior to this change it was possible to use an iOS-style app group ID on the Mac but that might result in some weird behaviour. Later sections of this post describe some of those problems. Of course, that information is now only of historical interest because, if you’re using an iOS-style app group, you can and should authorise that use with a provisioning profile. We also started seeding Xcode 16.3, which has since been release. This is aware of the Developer website change, and its Signing & Capabilities editor actively encourages you to use iOS-style app groups IDs in all products. Note This Xcode behaviour is the only option for iOS and its child platforms. With Xcode 16.3, it’s now the default for macOS as well. If you have existing project, enable this behaviour using the Register App Groups build setting. Finally, we updated a number of app group documentation pages, including App Groups entitlement and Configuring app groups. Crossing the Streams In some circumstances you might need to have a single app that accesses both an iOS- and a macOS-style app group. For example: You have a macOS app. You want to migrate to an iOS-style app group ID, perhaps because you want to share an app group container with a Mac Catalyst app. But you also need to access existing content in a container identified by a macOS-style app group ID. Historically this caused problems (FB16664827) but, as of Jun 2025, this is fully supported (r. 148552377). When the Developer website generates a Mac provisioning profile for an App ID with the App Groups capability, it automatically adds TEAM_ID.* to the list of app group IDs authorised by that profile (where TEAM_ID is your Team ID). This allows the app to claim access to every iOS-style app group ID associated with the App ID and any macOS-style app group IDs for that team. This helps in two circumstances: It avoids any Mac App Store Connect submission problems, because App Store Connect can see that the app’s profile authorises its use of all the it app group IDs it claims access to. Outside of App Store — for example, when you directly distribute an app using Developer ID signing — you no longer have to rely on macOS granting implicit access to macOS-style app group IDs. Rather, such access is explicitly authorised by your profile. That ensures that your entitlements remain validated, as discussed in the Entitlements-Validated Flag, below. A Historical Interlude These different styles of app group IDs have historical roots: On iOS, third-party apps have always used provisioning profiles, and thus the App Groups entitlement is restricted just like any other entitlement. On macOS, support for app groups was introduced before macOS had general support for provisioning profiles [1], and thus the App Groups entitlement is unrestricted. The unrestricted nature of this entitlement poses two problems. The first is accidental collisions. How do you prevent folks from accidentally using an app group ID that’s in use by some other developer? On iOS this is easy: The Developer website assigns each app group ID to a specific team, which guarantees uniqueness. macOS achieved a similar result by using the Team ID as a prefix. The second problem is malicious reuse. How do you prevent a Mac app from accessing the app group containers of some other team? Again, this isn’t an issue on iOS because the App Groups entitlement is restricted. On macOS the solution was for the Mac App Store to prevent you from publishing an app that used an app group ID that’s used by another team. However, this only works for Mac App Store apps. Directly distributed apps were free to access app group containers of any other app. That was considered acceptable back when the Mac App Store was first introduced. That’s no longer the case, which is why macOS 15 introduced app group container protection. See App Group Container Protection, below. [1] I’m specifically talking about provisioning profiles for directly distributed apps, that is, apps using Developer ID signing. Entitlements-Validated Flag The fact that the App Groups entitlement is unrestricted on macOS is, when you think about it, a little odd. The purpose of entitlements is to gate access to functionality. If an entitlement isn’t restricted, it’s not much of a gate! For most unrestricted entitlements that’s not a problem. Specifically, for both the App Sandbox and Hardened Runtime entitlements, those are things you opt in to, so macOS is happy to accept the entitlement at face value. After all, if you want to cheat you can just not opt in [1]. However, this isn’t the case for the App Groups entitlement, which actually gates access to functionality. Dealing with this requires macOS to walk a fine line between security and compatibility. Part of that solution is the entitlements-validated flag. When a process runs an executable, macOS checks its entitlements. There are two categories: Restricted entitlements must be authorised by a provisioning profile. If your process runs an executable that claims a restricted entitlement that’s not authorised by a profile, the system traps. Unrestricted entitlements don’t have to be authorised by a provisioning profile; they can be used by any code at any time. However, the App Groups entitlement is a special type of unrestricted entitlement called a validation-required entitlement. If a process runs an executable that claims a validation-required entitlement and that claim is not authorised by a profile, the system allows the process to continue running but clears its entitlements-validated flag. Some subsystems gate functionality on the entitlements-validated flag. For example, the data protection keychain uses entitlements as part of its access control model, but refuses to honour those entitlements if the entitlement-validated flag has been cleared. Note If you’re curious about this flag, use the procinfo subcommand of launchctl to view it. For example: % sudo launchctl procinfo `pgrep Test20230126` … code signing info = valid … entitlements validated … If the flag has been cleared, this line will be missing from the code signing info section. Historically this was a serious problem because it prevented you from creating an app that uses both app groups and the data protection keychain [2] (r. 104859788). Fortunately that’s no longer an issue because the Developer website now lets you include the App Groups entitlement in macOS provisioning profiles. [1] From the perspective of macOS checking entitlements at runtime. There are other checks: The App Sandbox is mandatory for Mac App Store apps, but that’s checked when you upload the app to App Store Connect. Directly distributed apps must be notarised to pass Gatekeeper, and the notary service requires that all executables enable the hardened runtime. [2] See TN3137 On Mac keychain APIs and implementations for more about the data protection keychain. App Groups and the Keychain The differences described above explain a historical oddity associated with keychain access. The Sharing access to keychain items among a collection of apps article says: Application groups When you collect related apps into an application group using the App Groups entitlement, they share access to a group container, and gain the ability to message each other in certain ways. You can use app group names as keychain access group names, without adding them to the Keychain Access Groups entitlement. On iOS this makes a lot of sense: The App Groups entitlement is a restricted entitlement on iOS. The Developer website assigns each iOS-style app group ID to a specific team, which guarantees uniqueness. The required group. prefix means that these keychain access groups can’t collide with other keychain access groups, which all start with an App ID prefix (there’s also Apple-only keychain access groups that start with other prefixes, like apple). However, this didn’t work on macOS [1] because the App Groups entitlement is unrestricted there. However, with the Feb 2025 changes it should now be possible to use an iOS-style app group ID as a keychain access group on macOS. Note I say “should” because I’ve not actually tried it (-: Keep in mind that standard keychain access groups are protected the same way on all platforms, using the restricted Keychain Access Groups entitlement (keychain-access-groups). [1] Except for Mac Catalyst apps and iOS Apps on Mac. Not Entirely Unsatisfied When you launch a Mac app that uses app groups you might see this log entry: type: error time: 10:41:35.858009+0000 process: taskgated-helper subsystem: com.apple.ManagedClient category: ProvisioningProfiles message: com.example.apple-samplecode.Test92322409: Unsatisfied entitlements: com.apple.security.application-groups Note The exact format of that log entry, and the circumstances under which it’s generated, varies by platform. On macOS 13.0.1 I was able to generate it by running a sandboxed app that claims a macOS-style app group ID in the App Groups entitlement and also claims some other restricted entitlement. This looks kinda worrying and can be the source of problems. It means that the App Groups entitlement claims an entitlement that’s not authorised by a provisioning profile. On iOS this would trap, but on macOS the system allows the process to continue running. It does, however, clear the entitlements-validate flag. See Entitlements-Validated Flag for an in-depth discussion of this. The easiest way to avoid this problem is to authorise your app group ID claims with a provisioning profile. If there’s some reason you can’t do that, watch out for potential problems with: The data protection keychain — See the discussion of that in the Entitlements-Validated Flag and App Groups and the Keychain sections, both above. App group container protection — See App Group Container Protection, below. App Group Container Protection macOS 15 introduced app group container protection. To access an app group container without user intervention: Claim access to the app group by listing its ID in the App Groups entitlement. Locate the container by calling the containerURL(forSecurityApplicationGroupIdentifier:) method. Ensure that at least one of the following criteria are met: Your app is deployed via the Mac App Store (A). Or via TestFlight when running on macOS 15.1 or later (B). Or the app group ID starts with your app’s Team ID (C). Or your app’s claim to the app group is authorised by a provisioning profile embedded in the app (D) [1]. If your app doesn’t follow these rules, the system prompts the user to approve its access to the container. If granted, that consent applies only for the duration of that app instance. For more on this, see: The System Integrity Protection section of the macOS Sequoia 15 Release Notes The System Integrity Protection section of the macOS Sequoia 15.1 Release Notes WWDC 2024 Session 10123 What’s new in privacy, starting at 12:23 The above criteria mean that you rarely run into the app group authorisation prompt. If you encounter a case where that happens, feel free to start a thread here on DevForums. See the top of this post for info on the topic and tags to use. Note Prior to the Feb 2025 change, things generally worked out fine when you app was deployed but you might’ve run into problems during development. That’s no longer the case. [1] This is what allows Mac Catalyst and iOS Apps on Mac to work. Revision History 2025-08-12 Added a reference to the Register App Groups build setting. 2025-07-28 Updated the Crossing the Streams section for the Jun 2025 change. Made other minor editorial changes. 2025-04-16 Rewrote the document now that iOS-style app group IDs are fully supported on the Mac. Changed the title from App Groups: macOS vs iOS: Fight! to App Groups: macOS vs iOS: Working Towards Harmony 2025-02-25 Fixed the Xcode version number mentioned in yesterday’s update. 2025-02-24 Added a quick update about the iOS-style app group IDs on macOS issue. 2024-11-05 Further clarified app group container protection. Reworked some other sections to account for this new reality. 2024-10-29 Clarified the points in App Group Container Protection. 2024-10-23 Fleshed out the discussion of app group container protection on macOS 15. 2024-09-04 Added information about app group container protection on macOS 15. 2023-01-31 Renamed the Not Entirely Unsatisfactory section to Not Entirely Unsatisfied. Updated it to describe the real impact of that log message. 2022-12-12 First posted.
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5.7k
Aug ’25
DeviceCheck.generateToken, Error: com.apple.devicecheck.error 0
Dear Apple Developer Support Team, We are experiencing a recurring issue with the DeviceCheck API where the following error is being returned: com.apple.devicecheck.error 0 Upon analyzing our logs, we have noticed that this error occurs significantly more often when users are connected to Wi-Fi networks, compared to mobile networks. This leads us to suspect that there might be a relationship between Wi-Fi configuration and the DeviceCheck service’s ability to generate or validate tokens. We would like to know: Is this error code (0) known to be caused by specific types of network behavior or misconfigurations on Wi-Fi networks (e.g., DNS filtering, firewall restrictions, proxy servers)? Are there any recommended best practices for ensuring reliable DeviceCheck API communication over Wi-Fi networks? Additionally, could you please clarify what general conditions could trigger this com.apple.devicecheck.error 0? The lack of specific documentation makes debugging this issue difficult from our side. Any guidance or internal documentation on this error code and its potential causes would be greatly appreciated. IDE: Xcode 16.3 Looking forward to your support. Best regards,
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177
May ’25
Passkey returns unknown error instead of excludedCredentials error when “Saving on another device” option is used.
Hello, I'm receiving an unknown error instead of the excluded credentials error when using the "Save on another device" option for Passkey creation. When creating the ASAuthorizationPlatformPublicKeyCredentialProvider request to pass to the ASAuthorizationController. The excludedCredentials property is used to add a list of credentials to exclude in the registration process. This is to prevent duplicate passkeys from being created if one already exists for the user. When trying to create a duplicate passkey using the same device, the ASAuthorizationControllerDelegate method authorizationController(controller, didCompleteWithError:) is called. The error received has localized description “At least one credential matches an entry of the excludeCredentials list in the platform attached authenticator." When trying to create a duplicate passkey using the “Save on another device” option. The delegate method is called, but the error received has code 1000 ("com.apple.AuthenticationServices.AuthorizationError" - code: 1000). Which maps to the unknown error case in ASAuthorization error type.
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322
May ’25
Production-Grade Implementation Guidance: DCError Matrices, Retry Strategies, and Simulator Testing for App Attest APIs
Hi there, We're implementing Apple's DeviceCheck App Attest for production iOS authentication. The public documentation defines DCError cases but doesn't specify which errors are expected per API method or recommend retry/remediation strategies. We need Apple's guidance to implement robust, production-aligned error handling before rollout. 1. Error Surface per API Method Question: Can you confirm the complete, officially expected set of DCError values for each method? We understand the following errors are possible across App Attest APIs: invalidKey invalidInput featureUnsupported serverUnavailable unknownSystemFailure Specifically, please confirm which errors can occur for: DCAppAttestService.generateKey() DCAppAttestService.attestKey(_:clientData:) DCAppAttestService.generateAssertion(keyID:clientData:) Are there any additional undocumented or edge-case errors we should handle? 2. Retry Strategy & Remediation Matrix Question: For each API method and error code, please help us with proposal around which errorCode is retriable, whats the remediation pre retry, retry cap and backoff strategy: Kindly also help with errors that are not covered here: Specific sub-questions: invalidKey handling: When this error occurs: Should the app delete the key and call generateKey again? Or should it fail the entire flow? serverUnavailable handling: Should we retry immediately, or wait before retrying? Is exponential backoff recommended? What's the recommended max retry count? Backoff strategy: Which errors (if any) qualify for exponential backoff? Recommended base delay, max delay, and jitter approach? When should we give up and fail the request? unknownSystemFailure: Is this retriable or should we fail? Any known causes or mitigations? 3. Simulator Testing Questions: Simulator API behavior: Can App Attest APIs be called normally on iOS Simulator? If not, is there a way to simulate for testing. Do they complete successfully with simulated attestations, or do they fail? Thanks, Nirekshitha
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331
Apr ’26
Get stuck on using ASWebAuthenticationSession and django allauth
I am trying to integrate those into my app, stuck on it would not transfer to view that inside app, can someone help? Scott
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134
Activity
Feb ’26
com.apple.developer.web-browser.public-key-credential still leads to com.apple.AuthenticationServices.AuthorizationError Code=1004
Hi, we were recently approved for the com.apple.developer.web-browser.public-key-credential entitlement and have added it to our app. It initially worked as expected for a couple of days, but then it stopped working. We're now seeing the same error as before adding the entitlement: Told not to present authorization sheet: Error Domain=com.apple.AuthenticationServicesCore.AuthorizationError Code=1 "(null)" ASAuthorizationController credential request failed with error: Error Domain=com.apple.AuthenticationServices.AuthorizationError Code=1004 "(null)" Do you have any insights into what might be causing this issue? Thank you!
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5
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526
Activity
Mar ’26
PCC VRE: 403 Forbidden when downloading SW Release 41303
Is anyone else seeing 403 errors for PCC VRE when trying to pull assets for Release 41303? My pccvre audit of the Transparency Log passes (valid root digests for 41385), but the download fails consistently on specific CDN URLs: Failed to download SW release asset... response: 403 I’ve verified csrutil allow-research-guests is active and the license is accepted. Release 41385 seems fine, but 41303 is a brick wall. Is this a known pull-back or a CDN permissions sync issue?
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216
Activity
3w
https://app-site-association.cdn-apple.com/a/v1/* 404 Not Found
% curl -v https://app-site-association.cdn-apple.com/a/v1/zfcs.bankts.cn Host app-site-association.cdn-apple.com:443 was resolved. IPv6: (none) IPv4: 218.92.226.151, 119.101.148.193, 218.92.226.6, 115.152.217.3 Trying 218.92.226.151:443... Connected to app-site-association.cdn-apple.com (218.92.226.151) port 443 ALPN: curl offers h2,http/1.1 (304) (OUT), TLS handshake, Client hello (1): CAfile: /etc/ssl/cert.pem CApath: none (304) (IN), TLS handshake, Server hello (2): (304) (IN), TLS handshake, Unknown (8): (304) (IN), TLS handshake, Certificate (11): (304) (IN), TLS handshake, CERT verify (15): (304) (IN), TLS handshake, Finished (20): (304) (OUT), TLS handshake, Finished (20): SSL connection using TLSv1.3 / AEAD-AES256-GCM-SHA384 / [blank] / UNDEF ALPN: server accepted http/1.1 Server certificate: subject: C=US; ST=California; O=Apple Inc.; CN=app-site-association.cdn-apple.com start date: Sep 25 13:58:08 2025 GMT expire date: Mar 31 17:44:25 2026 GMT subjectAltName: host "app-site-association.cdn-apple.com" matched cert's "app-site-association.cdn-apple.com" issuer: CN=Apple Public Server RSA CA 11 - G1; O=Apple Inc.; ST=California; C=US SSL certificate verify ok. using HTTP/1.x GET /a/v1/zfcs.bankts.cn HTTP/1.1 Host: app-site-association.cdn-apple.com User-Agent: curl/8.7.1 Accept: / Request completely sent off < HTTP/1.1 404 Not Found < Content-Type: text/plain; charset=utf-8 < Content-Length: 10 < Connection: keep-alive < Server: nginx < Date: Wed, 04 Feb 2026 02:26:00 GMT < Expires: Wed, 04 Feb 2026 02:26:10 GMT < Age: 24 < Apple-Failure-Details: {"cause":"context deadline exceeded (Client.Timeout exceeded while awaiting headers)"} < Apple-Failure-Reason: SWCERR00301 Timeout < Apple-From: https://zfcs.bankts.cn/.well-known/apple-app-site-association < Apple-Try-Direct: true < Vary: Accept-Encoding < Via: https/1.1 jptyo12-3p-pst-003.ts.apple.com (acdn/3.16363), http/1.1 jptyo12-3p-pac-043.ts.apple.com (acdn/3.16363), https/1.1 jptyo12-3p-pfe-002.ts.apple.com (acdn/3.16363) < X-Cache: MISS KS-CLOUD < CDNUUID: 736dc646-57fb-43c9-aa0d-eedad3a534f8-1154605242 < x-link-via: yancmp83:443;xmmp02:443;fzct321:443; < x-b2f-cs-cache: no-cache < X-Cache-Status: MISS from KS-CLOUD-FZ-CT-321-35 < X-Cache-Status: MISS from KS-CLOUD-XM-MP-02-16 < X-Cache-Status: MISS from KS-CLOUD-YANC-MP-83-15 < X-KSC-Request-ID: c4a640c815640ee93c263a357ee919d6 < CDN-Server: KSFTF < X-Cdn-Request-ID: c4a640c815640ee93c263a357ee919d6 < Not Found Connection #0 to host app-site-association.cdn-apple.com left intact
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1
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259
Activity
Feb ’26
Local network permission
Hi everyone, We are working on an app that requires access to devices on the local network (Bonjour / LAN discovery + direct socket communication). We are currently struggling with the Local Network privacy permission flow introduced by Apple. From our understanding, there is no dedicated public API to explicitly request Local Network permission or to reliably determine the current authorization state before attempting network activity. We have tried several commonly suggested approaches to trigger the permission dialog, including: Bonjour browsing via NWBrowser Publishing/listening with NetService UDP/TCP socket attempts on local subnet NWConnection / NWListener Triggering discovery after app launch and after foreground transitions We already added the required entries in: NSLocalNetworkUsageDescription NSBonjourServices However, the behavior is inconsistent across devices and OS versions: Sometimes the popup appears immediately Sometimes it never appears Sometimes network operations silently fail without callback clarity In some cases callbacks are delayed or ambiguous Reinstalling/resetting permissions changes behavior unpredictably Our main challenges are: What is currently considered the most reliable Apple-approved method to trigger the Local Network permission prompt? Is there any officially recommended way to determine whether permission is: not determined denied granted Is there any reliable callback or state transition API developers should use? Are there known differences between: NWBrowser NetService BSD sockets NWConnection when it comes to triggering the permission dialog? Are there recommended retry/timing patterns to avoid race conditions during app launch? Is Apple planning to introduce a dedicated authorization API similar to: AVAuthorizationStatus CLAuthorizationStatus PHPhotoLibrary.authorizationStatus() Right now it feels difficult to provide a reliable UX because there is no deterministic way to: proactively request access observe authorization state recover gracefully when the prompt does not appear Any guidance, DTS references, WWDC sessions, or recommended implementation patterns would be greatly appreciated. Thanks!
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9
Activity
5h
How to use App Attest Environment?
Hi, I'm looking at adding App Attest to an app, and I think I understand the mechanics of the attestation process, but I'm having trouble figuring out how development and testing are supposed to work. Two main questions: The "App Attest Environment" -- the documentation says that attestation requests made in the .development sandbox environment don't affect the app's risk metrics, but I'm not sure how to actually use this sandbox. My understanding is that one of the things App Attest does is to ensure that your app has been appropriately signed by the App Store, so it knows that it hasn't been tampered with. But the docs say that App Store builds (and Test Flight and Developer Enterprise Program) always use the .production environment. Does App Attest actually work for local developer-build apps if you have this entitlement set? Presumably only on hardware devices since it requires the Secure Enclave? Does our headend have to do something different when verifying the public key and subsequent attested requests for an app that's using the .development sandbox? The docs do mention that a headend server should potentially track two keys per device/user pair so that it can have a production and development key. How does the headend know if a key is from the sandbox environment? Thanks!
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0
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385
Activity
Jun ’25
passkey in iOS via iCloudKeyChain
I have a very basic binary question around passkeys. Assuming everything is on latest and greatest version with respect to iOS, when user starts creating a passkey in platform-authenticator i.e., iCloudKeyChain (Apple Password Manager) , will iCloudKeyChain create a hardware-bound passkey in secure-enclave i.e., is brand new key-pair created right inside Secure-enclave ? OR will the keypair be created in software i.e., software-bound-passkey ?? i.e., software-bound keypair and store the private-key locally in the device encrypted with a key that is of course created in secure-enclave.
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1
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0
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184
Activity
May ’25
Platform SSO: Biometric Prompt Behavior with userSecureEnclaveKey
I have a question regarding Platform SSO and the use of Secure Enclave–backed keys with biometric policies. If we configure userSecureEnclaveKeyBiometricPolicy with userSecureEnclaveKey, my understanding is that the Secure Enclave key is protected by biometric authentication (e.g., Face ID / Touch ID). In this setup, during a login request that also refreshes the id_token and refresh_token, the assertion is signed using the userSecureEnclaveKey. My question is: Will this signing operation trigger a biometric prompt every time the assertion is generated (i.e., during login/token refresh) ?
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0
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266
Activity
Mar ’26
App Attest attestationData request fails with 400 Bad Request (no X-Request-ID)
Hello Apple Team We are integrating App Attest with our backend and seeing a 400 Bad Request response when calling the attestation endpoint. The issue is that the response does not include an X-Request-ID or JSON error payload with id and code, which makes it hard to diagnose. Instead, it only returns a receipt blob. Request Details URL: https://data-development.appattest.apple.com/v1/attestationData Request Headers: Authorization: eyJraWQiOiI0RjVLSzRGV1JaIiwidHlwIjoiSldUIiwiYWxnIjoiRVMyNTYifQ.eyJpc3MiOiJOOVNVR1pNNjdRIiwiZXhwIjoxNzU3MDUxNTYwLCJpYXQiOjE3NTcwNDc5NjB9.MEQCIF236MqPCl6Vexg7RcPUMK8XQeACXogldnpuiNnGQnzgAiBQqASdbJ64g58xfWGpbzY3iohvxBSO5U5ZE3l87JjfmQ Content-Type: application/octet-stream Request Body: (Binary data, logged as [B@59fd7d35) Response Status: 400 Bad Request Response Headers: Date: Fri, 05 Sep 2025 04:52:40 GMT x-b3-traceid: 4c42e18094022424 x-b3-spanid: 4c42e18094022424 Response Body (truncated): "receipt": h'308006092A864886F70D01070... Problem The response does not include X-Request-ID. The response does not include JSON with id or code. Only a receipt blob is returned. Questions Can the x-b3-traceid be used by Apple to trace this failed request internally? Is it expected for some failures to return only a receipt blob without X-Request-ID? How should we interpret this error so we can handle it properly in production? Thanks in advance for your guidance.
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1
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752
Activity
Sep ’25
email sent to to an iCloud account is landed to junk when email sent from user-*dev*.company.com micro service
Our company has a micro service which sends a notification email to an iCloud account/email and the email is going to the junk folder. As we tested, the email generated from user-field.company.com goes to the Inbox, while the email from user-dev.company.com goes to the Junk folder. Is there a way to avoid sending the emails to client's Junk folder when the email is sent from a specific company domain?
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0
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0
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101
Activity
Feb ’26
App Review Guidelines 2.5.1 / 2.5.2 — official guidance on screen capture protection for sensitive content
Hi all, We are developing an iOS app that includes private user-to-user chats, commercial offer details with monetary value, and customer identification data. In line with OWASP MASVS-PLATFORM-3 requirements regarding unintentional sensitive data exposure, we need to protect these specific screens from screenshots and screen recording. We have carefully reviewed the relevant App Review Guidelines (2.5.1 on public APIs, 2.5.2 on self-contained bundles, 5.1.1 on privacy) and the related Human Interface Guidelines. From this analysis we have observed the following: iOS does not expose a public API to globally disable screen capture (no direct equivalent of Android's FLAG_SECURE). The SwiftUI .privacySensitive() modifier is effective for Lock Screen widgets and Always-On Display, but it does not appear to prevent screenshots or screen recording of an app's main UI while in the foreground. A number of widely distributed App Store apps (banking, authenticator, secure messaging) implement some form of screenshot protection on sensitive screens. Several established open-source libraries leverage the system behavior of UITextField with isSecureTextEntry as a wrapping container for arbitrary views, in order to achieve pixel-level protection for sensitive content. We would appreciate clarification on the following points: For privacy-driven protection of sensitive screens (private chats, customer data, monetized offers), is there an officially recommended approach we may have missed? Are there public APIs intended specifically for this use case beyond .privacySensitive()? Is the practice of leveraging UITextField with isSecureTextEntry as a wrapping container for arbitrary views considered an acceptable use of public APIs under Guideline 2.5.1, or does it carry App Review risk? Are there official recommendations or documentation for apps handling sensitive personal data that wish to align with industry standards such as OWASP MASVS-PLATFORM-3 for screenshot and screen recording leakage prevention? The intended use is strictly limited to a small number of screens marked as containing sensitive data (private messages, deal details, customer information). The protection would be selective and clearly communicated to the user via in-app messaging, not global to the app. Thanks in advance for any clarification, including pointers to existing documentation or threads we may have missed. Deployment target: iOS 15+
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4
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725
Activity
6d
AASA not being fetched immediately upon app install
Hi Apple Devs, For our app, we utilize passkeys for account creation (not MFA). This is mainly for user privacy, as there is 0 PII associated with passkey account creation, but it additionally also satisfies the 4.8: Login Services requirement for the App Store. However, we're getting blocked in Apple Review. Because the AASA does not get fetched immediately upon app install, the reviewers are not able to create an account immediately via passkeys, and then they reject the build. I'm optimistic I can mitigate the above. But even if we pass Apple Review, this is a pretty catastrophic issue for user security and experience. There are reports that 5% of users cannot create passkeys immediately (https://developer.apple.com/forums/thread/756740). That is a nontrivial amount of users, and this large of an amount distorts how app developers design onboarding and authentication flows towards less secure experiences: App developers are incentivized to not require MFA setup on account creation because requiring it causes significant churn, which is bad for user security. If they continue with it anyways, for mitigation, developers are essentially forced to add in copy into their app saying something along the lines of "We have no ability to force Apple to fetch the config required to continue sign up, so try again in a few minutes, you'll just have to wait." You can't even implement a fallback method. There's no way to check if the AASA is available before launching the ASAuthorizationController so you can't mitigate a portion of users encountering an error!! Any app that wants to use the PRF extension to encrypt core functionality (again, good for user privacy) simply cannot exist because the app simply does not work for an unspecified amount of time for a nontrivial portion of users. It feels like a. Apple should provide a syscall API that we can call to force SWCD to verify the AASA or b. implement a config based on package name for the app store such that the installation will immediately include a verified AASA from Apple's CDN. Flicking the config on would require talking with Apple. If this existed, this entire class of error would go away. It feels pretty shocking that there isn't a mitigation in place for this already given that it incentivizes app developers to pursue strictly less secure and less private authentication practices.
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0
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415
Activity
Aug ’25
ASCredentialProviderViewController Usage
override func prepareInterface(forPasskeyRegistration registrationRequest: any ASCredentialRequest) int this function how can i get the "challenge" from user agent, the params "challenge" need to be used in webauthn navigator.credentials.create
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1
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285
Activity
Jul ’25
LAContext and its usage in context of Local Authentication
While working with Local Authentication framework, specifically LAContext class I found myself with few contradictions to documentation, and although I believe that those differences are rather positive than negative, either documentation is lacking behind or those APIs are not working as intended - which I believe is combination of both. 1. Local Authentication 1.1 Biometry type, and associated with it hash With introduction of LADomainState one can extract underlying biometry type along it's (current) state hash this way: @available(iOS 18, macOS 15, *) func postIOS18() { let context = LAContext() let biometryType = context.domainState.biometry.biometryType // (1) let biometryStateHash = context.domainState.biometry.stateHash // (2) } prior to receiving above APIs, we would retrieve such information something along those lines: func preIOS18() { let context = LAContext() let policy: LAPolicy // ... var error: NSError? _ = context.canEvaluatePolicy(policy, error: error) // (3) // ... (Handle error - if present) let biometryType = context.biometryType // (4) let biometryStateHash = context.evaluatedPolicyDomainState // (5) } However, moving let biometryType = context.biometryType (4) before call to canEvaluatePolicy (3) still yields correct biometry type. This is in contradiction to article from Local Authentication documentation page Optionally, Adjust Your User Interface to Accommodate Face ID. Furthermore, biometryType documentation does not mentions such requirement. Another difference is that call to canEvaluatePolicy (3) might return an error, eg. LAError(.biometryLockout) (if implemented correctly) preventing as from returning biometryStateHash (5) with nil value. This is not the case for new API, where the same call (2) will yield nil as a result - LADomainStateBiometry documentation does not mention it. In summary, here are some questions: Which API should be used to retrieve biometry type?, and why the "older way" has not been deprecated? Is is safe to assume that calls to biometryType and stateHash from LADomainStateBiometry will produce meaningful results without prior call to canEvaluatePolicy? Should I assume that call to biometryType found on LAContext instance will always return biometryType without prior call to canEvaluatePolicy?, or perhaps those are only side effects of changes made to accommodate LADomainState, and prior to them (pre-iOS 18) we must call canEvaluatePolicy to get meaningful value. Are the stateHash properties found on LADomainState, LADomainStateBiometry and LADomainStateCompanion will return nil upon encountering any error under the hood? (which would be equivalent of below code, prior to iOS 18) func biometryStateHash() -> Data? { let context = LAContext() if #available(iOS 18, macOS 15, *) { _ = context.canEvaluatePolicy(policy, error: nil) return context.evaluatedPolicyDomainState } else { return context.domainState.biometry.stateHash } } 1.2 Deprecation of evaluatedDomainState There is a forum post LAContext.evaluatedPolicyDomainState change between major OS versions mentioning missing documentation (fixed), however there's still information missing of how they correlate to each other. From my findings, the deprecated evaluatedDomainState property value matches those of LADomainState stateHash (when no companion device is present), and LADomainStateBiometry stateHash (all the time). Are those assumptions correct? 1.3 LAContext (authenticated) session lifespan Theres is little information about it state when authenticated by the user. Documentation on LAContext does not mention this behavior, while there are hints that once authenticated, and context is reused, any farther calls will not prompt user with UI. The problem is that this behavior is little, to no documented. Here are few examples I have found: Logging a User into Your App with Face ID or Touch ID (code sample) contains comment // Get a fresh context for each login. If you use the same context on multiple attempts //  (by commenting out the next line), then a previously successful authentication //  causes the next policy evaluation to succeed without testing biometry again. //  That's usually not what you want. Recent forum post, where such approach is mentioned by Quinn 'The Eskimo!' "At the API level, one option you have is to create an LAContext and pass it in to each SecItemCopyMatching call via kSecUseAuthenticationContext." WWDC22 Streamline local authorization flows session "By binding the LAContext to our private key reference, we ensure that executing the signature operation will not trigger another authentication, while allowing the operation to continue without unnecessary prompts. These binding also means that no additional user interactions will be required for future signatures until the LAContext is invalidated." Furthermore this is complicated by the touchIDAuthenticationAllowableReuseDuration property from LAContext instance which states that "The default value is 0, meaning that no previous biometric unlock can be reused." which is in direct contradiction to what I have experienced while working with LAContext and sources mentioned above. While digging on this, whether this behavior is intended or not, I came across a post (I would love to share it, but the domain is not permitted) that shared the same findings (and concerns) regarding LAContext behavior as me. The author also provided a FB9984036 feedback number - although no further update was made on that topic. So my questions are: Is it safe to reuse LAContext (authenticated) instance? How long such instance is considered authenticated?, is it a time duration or perhaps it stays in authenticated state until explicitly invalidated using invalidate method. (its invalidated for sure when app is terminated, but this was to be expected :)) How does touchIDAuthenticationAllowableReuseDuration work, and how does it correlate to "reusability" of the authenticated LAContext instance? In what scenarios touchIDAuthenticationAllowableReuseDuration should be used and what is its expected behavior? (I have tried it both on iOS and macOS; from my perspective API this does not "work")
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5h
Customize the Auth System popup
Hello I'm using Auth0 for handling auth in my app When the user wants to sign in, it will show the auth system pop-up And when the user wants to log out it shows the same pop-up My issue is how to replace the Sign In text in this pop-up to show Sign Out instead of Sign In when the user wants to sign out?
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Activity
Sep ’25
Password AutoFill does not pick up saved password in developer mode
Without developer mode, I was able to get Password AutoFill to work in my SwiftUI app with my local Vapor server using ngrok and adding the Associated Domains capability with the value webcredentials:....ngrok-free.app and the respective apple-app-site-association file on my local server in /.well-known/. (works on device, but not in the simulator). However, if I use the developer mode (webcredentials:....ngrok-free.app?mode=developer) it only works halfway when running from Xcode: I get asked to save the password, but the saved passwords are not picked up, when I try to login again. Neither on device, nor in the simulator. If I remove the ?mode=developer it seems to work as expected. Is this by design, or am I missing something? var body: some View { ... Section(header: Text("Email")) { TextField("Email", text: $viewModel.credentials.username) .textContentType(.username) .autocapitalization(.none) .keyboardType(.emailAddress) } Section(header: Text("Passwort")) { SecureField("Passwort", text: $viewModel.credentials.password) .textContentType(.password) } ... }
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May ’25
App Groups: macOS vs iOS: Working Towards Harmony
I regularly see folks confused by the difference in behaviour of app groups between macOS and iOS. There have been substantial changes in this space recently. While much of this is now covered in the official docs (r. 92322409), I’ve updated this post to go into all the gory details. If you have questions or comments, start a new thread with the details. Put it in the App & System Services > Core OS topic area and tag it with Code Signing and Entitlements. Oh, and if your question is about app group containers, also include Files and Storage. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" App Groups: macOS vs iOS: Working Towards Harmony There are two styles of app group ID: iOS-style app group IDs start with group., for example, group.eskimo1.test. macOS-style app group IDs start with your Team ID, for example, SKMME9E2Y8.eskimo1.test. This difference has been the source of numerous weird problems over the years. Starting in Feb 2025, iOS-style app group IDs are fully supported on macOS for all product types [1]. If you’re writing new code that uses app groups, use an iOS-style app group ID. If you have existing code that uses a macOS-style app group ID, consider how you might transition to the iOS style. IMPORTANT The Feb 2025 changes aren’t tied to an OS release but rather to a Developer website update. For more on this, see Feb 2025 Changes, below. [1] If your product is a standalone executable, like a daemon or agent, wrap it in an app-like structure, as explained in Signing a daemon with a restricted entitlement. iOS-Style App Group IDs An iOS-style app group ID has the following features: It starts with the group. prefix, for example, group.eskimo1.test. You allocate it on the Developer website. This assigns the app group ID to your team. You then claim access to it by listing it in the App Groups entitlement (com.apple.security.application-groups) entitlement. That claim must be authorised by a provisioning profile [1]. The Developer website will only let you include your team’s app group IDs in your profile. For more background on provisioning profiles, see TN3125 Inside Code Signing: Provisioning Profiles. iOS-style app group IDs originated on iOS with iOS 3.0. They’ve always been supported on iOS’s child platforms (iPadOS, tvOS, visionOS, and watchOS). On the Mac: They’ve been supported by Mac Catalyst since that technology was introduced. Likewise for iOS Apps on Mac. Starting in Feb 2025, they’re supported for other Mac products. [1] Strictly speaking macOS does not require that, but if your claim is not authorised by a profile then you might run into other problems. See Entitlements-Validated Flag, below. macOS-Style App Group IDs A macOS-style app group ID has the following features: It should start with your Team ID [1], for example, SKMME9E2Y8.eskimo1.test. It can’t be explicitly allocated on the Developer website. Code that isn’t sandboxed doesn’t need to claim the app group ID in the App Groups entitlement. [2] To use an app group, claim the app group ID in the App Groups entitlement. The App Groups entitlement is not restricted on macOS, meaning that this claim doesn’t need to be authorised by a provisioning profile [3]. However, if you claim an app group ID that’s not authorised in some way, you might run into problems. More on that later in this post. If you submit an app to the Mac App Store, the submission process checks that your app group IDs make sense, that is, they either start with your Team ID (macOS style) or are assigned to your team (iOS style). [1] This is “should” because, historically, macOS has not actually required it. However, that’s now changing, with things like app group container protection. [2] This was true prior to macOS 15. It may still technically be true in macOS 15 and later, but the most important thing, access to the app group container, requires the entitlement because of app group container protection. [3] Technically it’s a validation-required entitlement, something that we’ll come back to in the Entitlements-Validated Flag section. Feb 2025 Changes On 21 Feb 2025 we rolled out a change to the Developer website that completes the support for iOS-style app group IDs on the Mac. Specifically, it’s now possible to create a Mac provisioning profile that authorises the use of an iOS-style app group ID. Note This change doesn’t affect Mac Catalyst or iOS Apps on Mac, which have always been able to use iOS-style app group IDs on the Mac. Prior to this change it was possible to use an iOS-style app group ID on the Mac but that might result in some weird behaviour. Later sections of this post describe some of those problems. Of course, that information is now only of historical interest because, if you’re using an iOS-style app group, you can and should authorise that use with a provisioning profile. We also started seeding Xcode 16.3, which has since been release. This is aware of the Developer website change, and its Signing & Capabilities editor actively encourages you to use iOS-style app groups IDs in all products. Note This Xcode behaviour is the only option for iOS and its child platforms. With Xcode 16.3, it’s now the default for macOS as well. If you have existing project, enable this behaviour using the Register App Groups build setting. Finally, we updated a number of app group documentation pages, including App Groups entitlement and Configuring app groups. Crossing the Streams In some circumstances you might need to have a single app that accesses both an iOS- and a macOS-style app group. For example: You have a macOS app. You want to migrate to an iOS-style app group ID, perhaps because you want to share an app group container with a Mac Catalyst app. But you also need to access existing content in a container identified by a macOS-style app group ID. Historically this caused problems (FB16664827) but, as of Jun 2025, this is fully supported (r. 148552377). When the Developer website generates a Mac provisioning profile for an App ID with the App Groups capability, it automatically adds TEAM_ID.* to the list of app group IDs authorised by that profile (where TEAM_ID is your Team ID). This allows the app to claim access to every iOS-style app group ID associated with the App ID and any macOS-style app group IDs for that team. This helps in two circumstances: It avoids any Mac App Store Connect submission problems, because App Store Connect can see that the app’s profile authorises its use of all the it app group IDs it claims access to. Outside of App Store — for example, when you directly distribute an app using Developer ID signing — you no longer have to rely on macOS granting implicit access to macOS-style app group IDs. Rather, such access is explicitly authorised by your profile. That ensures that your entitlements remain validated, as discussed in the Entitlements-Validated Flag, below. A Historical Interlude These different styles of app group IDs have historical roots: On iOS, third-party apps have always used provisioning profiles, and thus the App Groups entitlement is restricted just like any other entitlement. On macOS, support for app groups was introduced before macOS had general support for provisioning profiles [1], and thus the App Groups entitlement is unrestricted. The unrestricted nature of this entitlement poses two problems. The first is accidental collisions. How do you prevent folks from accidentally using an app group ID that’s in use by some other developer? On iOS this is easy: The Developer website assigns each app group ID to a specific team, which guarantees uniqueness. macOS achieved a similar result by using the Team ID as a prefix. The second problem is malicious reuse. How do you prevent a Mac app from accessing the app group containers of some other team? Again, this isn’t an issue on iOS because the App Groups entitlement is restricted. On macOS the solution was for the Mac App Store to prevent you from publishing an app that used an app group ID that’s used by another team. However, this only works for Mac App Store apps. Directly distributed apps were free to access app group containers of any other app. That was considered acceptable back when the Mac App Store was first introduced. That’s no longer the case, which is why macOS 15 introduced app group container protection. See App Group Container Protection, below. [1] I’m specifically talking about provisioning profiles for directly distributed apps, that is, apps using Developer ID signing. Entitlements-Validated Flag The fact that the App Groups entitlement is unrestricted on macOS is, when you think about it, a little odd. The purpose of entitlements is to gate access to functionality. If an entitlement isn’t restricted, it’s not much of a gate! For most unrestricted entitlements that’s not a problem. Specifically, for both the App Sandbox and Hardened Runtime entitlements, those are things you opt in to, so macOS is happy to accept the entitlement at face value. After all, if you want to cheat you can just not opt in [1]. However, this isn’t the case for the App Groups entitlement, which actually gates access to functionality. Dealing with this requires macOS to walk a fine line between security and compatibility. Part of that solution is the entitlements-validated flag. When a process runs an executable, macOS checks its entitlements. There are two categories: Restricted entitlements must be authorised by a provisioning profile. If your process runs an executable that claims a restricted entitlement that’s not authorised by a profile, the system traps. Unrestricted entitlements don’t have to be authorised by a provisioning profile; they can be used by any code at any time. However, the App Groups entitlement is a special type of unrestricted entitlement called a validation-required entitlement. If a process runs an executable that claims a validation-required entitlement and that claim is not authorised by a profile, the system allows the process to continue running but clears its entitlements-validated flag. Some subsystems gate functionality on the entitlements-validated flag. For example, the data protection keychain uses entitlements as part of its access control model, but refuses to honour those entitlements if the entitlement-validated flag has been cleared. Note If you’re curious about this flag, use the procinfo subcommand of launchctl to view it. For example: % sudo launchctl procinfo `pgrep Test20230126` … code signing info = valid … entitlements validated … If the flag has been cleared, this line will be missing from the code signing info section. Historically this was a serious problem because it prevented you from creating an app that uses both app groups and the data protection keychain [2] (r. 104859788). Fortunately that’s no longer an issue because the Developer website now lets you include the App Groups entitlement in macOS provisioning profiles. [1] From the perspective of macOS checking entitlements at runtime. There are other checks: The App Sandbox is mandatory for Mac App Store apps, but that’s checked when you upload the app to App Store Connect. Directly distributed apps must be notarised to pass Gatekeeper, and the notary service requires that all executables enable the hardened runtime. [2] See TN3137 On Mac keychain APIs and implementations for more about the data protection keychain. App Groups and the Keychain The differences described above explain a historical oddity associated with keychain access. The Sharing access to keychain items among a collection of apps article says: Application groups When you collect related apps into an application group using the App Groups entitlement, they share access to a group container, and gain the ability to message each other in certain ways. You can use app group names as keychain access group names, without adding them to the Keychain Access Groups entitlement. On iOS this makes a lot of sense: The App Groups entitlement is a restricted entitlement on iOS. The Developer website assigns each iOS-style app group ID to a specific team, which guarantees uniqueness. The required group. prefix means that these keychain access groups can’t collide with other keychain access groups, which all start with an App ID prefix (there’s also Apple-only keychain access groups that start with other prefixes, like apple). However, this didn’t work on macOS [1] because the App Groups entitlement is unrestricted there. However, with the Feb 2025 changes it should now be possible to use an iOS-style app group ID as a keychain access group on macOS. Note I say “should” because I’ve not actually tried it (-: Keep in mind that standard keychain access groups are protected the same way on all platforms, using the restricted Keychain Access Groups entitlement (keychain-access-groups). [1] Except for Mac Catalyst apps and iOS Apps on Mac. Not Entirely Unsatisfied When you launch a Mac app that uses app groups you might see this log entry: type: error time: 10:41:35.858009+0000 process: taskgated-helper subsystem: com.apple.ManagedClient category: ProvisioningProfiles message: com.example.apple-samplecode.Test92322409: Unsatisfied entitlements: com.apple.security.application-groups Note The exact format of that log entry, and the circumstances under which it’s generated, varies by platform. On macOS 13.0.1 I was able to generate it by running a sandboxed app that claims a macOS-style app group ID in the App Groups entitlement and also claims some other restricted entitlement. This looks kinda worrying and can be the source of problems. It means that the App Groups entitlement claims an entitlement that’s not authorised by a provisioning profile. On iOS this would trap, but on macOS the system allows the process to continue running. It does, however, clear the entitlements-validate flag. See Entitlements-Validated Flag for an in-depth discussion of this. The easiest way to avoid this problem is to authorise your app group ID claims with a provisioning profile. If there’s some reason you can’t do that, watch out for potential problems with: The data protection keychain — See the discussion of that in the Entitlements-Validated Flag and App Groups and the Keychain sections, both above. App group container protection — See App Group Container Protection, below. App Group Container Protection macOS 15 introduced app group container protection. To access an app group container without user intervention: Claim access to the app group by listing its ID in the App Groups entitlement. Locate the container by calling the containerURL(forSecurityApplicationGroupIdentifier:) method. Ensure that at least one of the following criteria are met: Your app is deployed via the Mac App Store (A). Or via TestFlight when running on macOS 15.1 or later (B). Or the app group ID starts with your app’s Team ID (C). Or your app’s claim to the app group is authorised by a provisioning profile embedded in the app (D) [1]. If your app doesn’t follow these rules, the system prompts the user to approve its access to the container. If granted, that consent applies only for the duration of that app instance. For more on this, see: The System Integrity Protection section of the macOS Sequoia 15 Release Notes The System Integrity Protection section of the macOS Sequoia 15.1 Release Notes WWDC 2024 Session 10123 What’s new in privacy, starting at 12:23 The above criteria mean that you rarely run into the app group authorisation prompt. If you encounter a case where that happens, feel free to start a thread here on DevForums. See the top of this post for info on the topic and tags to use. Note Prior to the Feb 2025 change, things generally worked out fine when you app was deployed but you might’ve run into problems during development. That’s no longer the case. [1] This is what allows Mac Catalyst and iOS Apps on Mac to work. Revision History 2025-08-12 Added a reference to the Register App Groups build setting. 2025-07-28 Updated the Crossing the Streams section for the Jun 2025 change. Made other minor editorial changes. 2025-04-16 Rewrote the document now that iOS-style app group IDs are fully supported on the Mac. Changed the title from App Groups: macOS vs iOS: Fight! to App Groups: macOS vs iOS: Working Towards Harmony 2025-02-25 Fixed the Xcode version number mentioned in yesterday’s update. 2025-02-24 Added a quick update about the iOS-style app group IDs on macOS issue. 2024-11-05 Further clarified app group container protection. Reworked some other sections to account for this new reality. 2024-10-29 Clarified the points in App Group Container Protection. 2024-10-23 Fleshed out the discussion of app group container protection on macOS 15. 2024-09-04 Added information about app group container protection on macOS 15. 2023-01-31 Renamed the Not Entirely Unsatisfactory section to Not Entirely Unsatisfied. Updated it to describe the real impact of that log message. 2022-12-12 First posted.
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Aug ’25
DeviceCheck.generateToken, Error: com.apple.devicecheck.error 0
Dear Apple Developer Support Team, We are experiencing a recurring issue with the DeviceCheck API where the following error is being returned: com.apple.devicecheck.error 0 Upon analyzing our logs, we have noticed that this error occurs significantly more often when users are connected to Wi-Fi networks, compared to mobile networks. This leads us to suspect that there might be a relationship between Wi-Fi configuration and the DeviceCheck service’s ability to generate or validate tokens. We would like to know: Is this error code (0) known to be caused by specific types of network behavior or misconfigurations on Wi-Fi networks (e.g., DNS filtering, firewall restrictions, proxy servers)? Are there any recommended best practices for ensuring reliable DeviceCheck API communication over Wi-Fi networks? Additionally, could you please clarify what general conditions could trigger this com.apple.devicecheck.error 0? The lack of specific documentation makes debugging this issue difficult from our side. Any guidance or internal documentation on this error code and its potential causes would be greatly appreciated. IDE: Xcode 16.3 Looking forward to your support. Best regards,
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Activity
May ’25
Passkey returns unknown error instead of excludedCredentials error when “Saving on another device” option is used.
Hello, I'm receiving an unknown error instead of the excluded credentials error when using the "Save on another device" option for Passkey creation. When creating the ASAuthorizationPlatformPublicKeyCredentialProvider request to pass to the ASAuthorizationController. The excludedCredentials property is used to add a list of credentials to exclude in the registration process. This is to prevent duplicate passkeys from being created if one already exists for the user. When trying to create a duplicate passkey using the same device, the ASAuthorizationControllerDelegate method authorizationController(controller, didCompleteWithError:) is called. The error received has localized description “At least one credential matches an entry of the excludeCredentials list in the platform attached authenticator." When trying to create a duplicate passkey using the “Save on another device” option. The delegate method is called, but the error received has code 1000 ("com.apple.AuthenticationServices.AuthorizationError" - code: 1000). Which maps to the unknown error case in ASAuthorization error type.
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Activity
May ’25
Production-Grade Implementation Guidance: DCError Matrices, Retry Strategies, and Simulator Testing for App Attest APIs
Hi there, We're implementing Apple's DeviceCheck App Attest for production iOS authentication. The public documentation defines DCError cases but doesn't specify which errors are expected per API method or recommend retry/remediation strategies. We need Apple's guidance to implement robust, production-aligned error handling before rollout. 1. Error Surface per API Method Question: Can you confirm the complete, officially expected set of DCError values for each method? We understand the following errors are possible across App Attest APIs: invalidKey invalidInput featureUnsupported serverUnavailable unknownSystemFailure Specifically, please confirm which errors can occur for: DCAppAttestService.generateKey() DCAppAttestService.attestKey(_:clientData:) DCAppAttestService.generateAssertion(keyID:clientData:) Are there any additional undocumented or edge-case errors we should handle? 2. Retry Strategy & Remediation Matrix Question: For each API method and error code, please help us with proposal around which errorCode is retriable, whats the remediation pre retry, retry cap and backoff strategy: Kindly also help with errors that are not covered here: Specific sub-questions: invalidKey handling: When this error occurs: Should the app delete the key and call generateKey again? Or should it fail the entire flow? serverUnavailable handling: Should we retry immediately, or wait before retrying? Is exponential backoff recommended? What's the recommended max retry count? Backoff strategy: Which errors (if any) qualify for exponential backoff? Recommended base delay, max delay, and jitter approach? When should we give up and fail the request? unknownSystemFailure: Is this retriable or should we fail? Any known causes or mitigations? 3. Simulator Testing Questions: Simulator API behavior: Can App Attest APIs be called normally on iOS Simulator? If not, is there a way to simulate for testing. Do they complete successfully with simulated attestations, or do they fail? Thanks, Nirekshitha
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Apr ’26