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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Best Practice for Keychain Storage for a C++ Plugin in a Host App (Maya)?
Hi everyone, I'm developing a C++ plugin (.bundle) for a third-party host application (Autodesk Maya) on macOS, and I'm finalizing the design for our licensing system. The plugin is distributed outside the Mac App Store. My goal is to securely store a license key in the user's Keychain. After some research, my proposed implementation is as follows: On activation, store the license data in the user's login keychain as a Generic Password (kSecClassGenericPassword) using the SecItem APIs. To ensure the plugin can access the item when loaded by Maya, I will use a specific Keychain Access Group (e.g., MY_TEAM_ID.com.mywebsite). The final .bundle will be code-signed with our company's Developer ID certificate. The signature will include an entitlements file (.entitlements) that specifies the matching keychain-access-groups permission. My understanding is that this combination of a unique Keychain Access Group and a properly signed/entitled bundle is the key to getting reliable Keychain access. This should also correctly trigger the one-time user permission prompt on first use. Does this sound like the correct and most robust approach for this scenario? Are there any common pitfalls with a plugin's Keychain access from within a host app that I should be aware of? Thanks for any feedback!
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160
Jun ’25
App Attest Issue in Production - Attestation Object Size Increased
Hi Apple Team and Community, We encountered a sudden and widespread failure related to the App Attest service on Friday, July 25, starting at around 9:22 AM UTC. After an extended investigation, our network engineers noted that the size of the attestation objects received from the attestKey call grew in size notably starting at that time. As a result, our firewall began blocking the requests from our app made to our servers with the Base64-encoded attestation objects in the payload, as these requests began triggering our firewall's max request length rule. Could Apple engineers please confirm whether there was any change rolled out by Apple at or around that time that would cause the attestation object size to increase? Can anyone else confirm seeing this? Any insights from Apple or others would be appreciated to ensure continued stability. Thanks!
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455
Jul ’25
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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526
Mar ’26
DCError.invalidInput on generateAssertion() - Affecting Small Subset of Users
Issue Summary I'm encountering a DCError.invalidInput error when calling DCAppAttestService.shared.generateAssertion() in my App Attest implementation. This issue affects only a small subset of users - the majority of users can successfully complete both attestation and assertion flows without any issues. According to Apple Engineer feedback, there might be a small implementation issue in my code. Key Observations Success Rate: ~95% of users complete the flow successfully Failure Pattern: The remaining ~5% consistently fail at assertion generation Key Length: Logs show key length of 44 characters for both successful and failing cases Consistency: Users who experience the error tend to experience it consistently Platform: Issue observed across different iOS versions and device types Environment iOS App Attest implementation Using DCAppAttestService for both attestation and assertion Custom relying party server communication Issue affects ~5% of users consistently Key Implementation Details 1. Attestation Flow (Working) The attestation process works correctly: // Generate key and attest (successful for all users) self.attestService.generateKey { keyId, keyIdError in guard keyIdError == nil, let keyId = keyId else { return completionHandler(.failure(.dcError(keyIdError as! DCError))) } // Note: keyId length is consistently 44 characters for both successful and failing users // Attest key with Apple servers self.attestKey(keyId, clientData: clientData) { result in // ... verification with RP server // Key is successfully stored for ALL users (including those who later fail at assertion) } } 2. Assertion Flow (Failing for ~5% of Users with invalidInput) The assertion generation fails for a consistent subset of users: // Get assertion data from RP server self.assertRelyingParty.getAssertionData(kid, with: data) { result in switch result { case .success(let receivedData): let session = receivedData.session let clientData = receivedData.clientData let hash = clientData.toSHA256() // SHA256 hash of client data // THIS CALL FAILS WITH invalidInput for ~5% of users // Same keyId (44 chars) that worked for attestation self.attestService.generateAssertion(kid, clientDataHash: hash) { assertion, err in guard err == nil, let assertion = assertion else { // Error: DCError.invalidInput if let err = err as? DCError, err.code == .invalidKey { return reattestAndAssert(.invalidKey, completionHandler) } else { return completionHandler(.failure(.dcError(err as! DCError))) } } // ... verification logic } } } 3. Client Data Structure Client data JSON structure (identical for successful and failing users): // For attestation (works for all users) let clientData = ["challenge": receivedData.challenge] // For assertion (fails for ~5% of users with same structure) var clientData = ["challenge": receivedData.challenge] if let data = data { // Additional data for assertion clientData["account"] = data["account"] clientData["amount"] = data["amount"] } 4. SHA256 Hash Implementation extension Data { public func toSHA256() -> Data { return Data(SHA256.hash(data: self)) } } 5. Key Storage Implementation Using UserDefaults for key storage (works consistently for all users): private let keyStorageTag = "app-attest-keyid" func setKey(_ keyId: String) -> Result<(), KeyStorageError> { UserDefaults.standard.set(keyId, forKey: keyStorageTag) return .success(()) } func getKey() -> Result<String?, KeyStorageError> { let keyId = UserDefaults.standard.string(forKey: keyStorageTag) return .success(keyId) } Questions User-Specific Factors: Since this affects only ~5% of users consistently, could there be device-specific, iOS version-specific, or account-specific factors that cause invalidInput? Key State Validation: Is there any way to validate the state of an attested key before calling generateAssertion()? The key length (44 chars) appears normal for both successful and failing cases. Keychain vs UserDefaults: Could the issue be related to using UserDefaults instead of Keychain for key storage? Though this works for 95% of users. Race Conditions: Could there be subtle race conditions or timing issues that only affect certain users/devices? Error Recovery: Is there a recommended way to handle this error? Should we attempt re-attestation for these users? Additional Context & Debugging Attempts Consistent Failure: Users who experience this error typically experience it on every attempt Key Validation: Both successful and failing users have identical key formats (44 character strings) Device Diversity: Issue observed across different device models and iOS versions Server Logs: Our server successfully provides challenges and processes attestation for all users Re-attestation: Forcing re-attestation sometimes resolves the issue temporarily, but it often recurs The fact that 95% of users succeed with identical code suggests there might be some environmental or device-specific factor that we're not accounting for. Any insights into what could cause invalidInput for a subset of users would be invaluable.
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573
Jun ’25
Keychain Sharing not working after Updating the Team ID
We are facing an issue with Keychain sharing across our apps after our Team ID was updated. Below are the steps we have already tried and the current observations: Steps we have performed so far: After our Team ID changed, we opened and re-saved all the provisioning profiles. We created a Keychain Access Group: xxxx.net.soti.mobicontrol (net.soti.mobicontrol is one bundle id of one of the app) and added it to the entitlements of all related apps. We are saving and reading certificates using this access group only. Below is a sample code snippet we are using for the query: [genericPasswordQuery setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass]; [genericPasswordQuery setObject:identifier forKey:(id)kSecAttrGeneric]; [genericPasswordQuery setObject:accessGroup forKey:(id)kSecAttrAccessGroup]; [genericPasswordQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit]; [genericPasswordQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes]; Issues we are facing: Keychain items are not being shared consistently across apps. We receive different errors at different times: Sometimes errSecDuplicateItem (-25299), even when there is no item in the Keychain. Sometimes it works in a debug build but fails in Ad Hoc / TestFlight builds. The behavior is inconsistent and unpredictable. Expectation / Clarification Needed from Apple: Are we missing any additional configuration steps after the Team ID update? Is there a known issue with Keychain Access Groups not working correctly in certain build types (Debug vs AdHoc/TestFlight)? Guidance on why we are intermittently getting -25299 and how to properly reset/re-add items in the Keychain. Any additional entitlement / provisioning profile configuration that we should double-check. Request you to please raise a support ticket with Apple Developer Technical Support including the above details, so that we can get guidance on the correct setup and resolve this issue.
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435
Sep ’25
Permission requirements for LAContext's canEvaluatePolicy
Hi, I am developing an app that checks if biometric authentication capabilities (Face ID and Touch ID) are available on a device. I have a few questions: Do I need to include a privacy string in my app to use the LAContext's canEvaluatePolicy function? This function checks if biometric authentication is available on the device, but does not actually trigger the authentication. From my testing, it seems like a privacy declaration is only required when using LAContext's evaluatePolicy function, which would trigger the biometric authentication. Can you confirm if this is the expected behavior across all iOS versions and iPhone models? When exactly does the biometric authentication permission pop-up appear for users - is it when calling canEvaluatePolicy or evaluatePolicy? I want to ensure my users have a seamless experience. Please let me know if you have any insights on these questions. I want to make sure I'm handling the biometric authentication functionality correctly in my app. Thank you!
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183
Jun ’25
MSAL framework return force authentication
Hi, We are using the MSAL library to authenticate users, with SSO authentication implemented through the Microsoft Authenticator app. The problem is that once or twice a day, a prompt for forced authentication appears, indicating that silent token acquisition is failing and resulting in a requirement for forced authentication. Below are some of the logs: ================================================= 2025-08-28 11:00:05.034 [Info] [AppDelegate.swift:121] application(:didFinishLaunchingWithOptions:) > MSAL message: TID=751353 MSAL 1.8.1 iOS 18.5 [2025-08-28 10:00:05 - EC9D1457-2D70-4878-926F-553391EBC9D3] [MSAL] Silent flow finished. Result (null), error: -51115 error domain: MSIDErrorDomain 2025-08-28 11:00:05.034 [Info] [AppDelegate.swift:121] application(:didFinishLaunchingWithOptions:) > MSAL message: TID=751353 MSAL 1.8.1 iOS 18.5 [2025-08-28 10:00:05 - EC9D1457-2D70-4878-926F-553391EBC9D3] [MSAL] acquireTokenSilent returning with error: (MSALErrorDomain, -50002) Masked(not-null) ==================================================== We initially raised this issue with Microsoft, but according to them: In the app's logs, the single one failure it contains, was when the SSO extension returned the error com.apple.AuthenticationServices.AuthorizationError, -6000 during a silent call. This error code is generated by the system framework (Apple), not by our code. It indicates that the framework encountered an unexpected internal issue before or after calling the SSO extension. MSAL returning interaction_required to the client app is the most effective way to recover from this error (as you mention, after the user selects the account the app continues working as expected). Additionally, as you also mention, the interactive call is made by switching to Authenticator (not displaying a "window" without leaving Eva Lite app), which means MSAL is not able to use the SSO extension and is using the fallback to legacy authentication. The recommended next step is for the customer to request support directly from Apple as this is an issue on their side. Additionally, the customer can also try to update to the latest iOS, in case Apple has already fixed this issue. ============================================= STEPS TO REPRODUCE There is no such steps its just that this is an enterprise application which is getting used on managed devices[iPhone 14]. The device are managed using some intune policy. Platform and Version: iOS Development Environment: Xcode 15, macOS 13.6.1 Run-time Configuration: iOS 18 Please let me know if there are any solutions to resolve this problem. Thank you.
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Sep ’25
App Attest development server (data-development.appattest.apple.com) returns 403 for CBOR attestation request
Hi, I’m currently implementing App Attest attestation validation on the development server. However, I’m receiving a 403 Forbidden response when I POST a CBOR-encoded payload to the following endpoint: curl -X POST -H "Content-Type: application/cbor" --data-binary @payload.cbor 'https://data-development.appattest.apple.com' Here’s how I’m generating the CBOR payload in Java: Map&lt;String, Object&gt; payload = new HashMap&lt;&gt;(); payload.put("attestation", attestationBytes); // byte[] from DCAppAttestService payload.put("clientDataHash", clientDataHash); // SHA-256 hash of the challenge (byte[]) payload.put("keyId", keyIdBytes); // Base64-decoded keyId (byte[]) payload.put("appId", TEAM_ID + "." + BUNDLE_ID); // e.g., "ABCDE12345.com.example.app" ObjectMapper cborMapper = new ObjectMapper(new CBORFactory()); byte[] cborBody = cborMapper.writeValueAsBytes(payload); I’m unsure whether the endpoint is rejecting the payload format or if the endpoint itself is incorrect for this stage. I’d appreciate clarification on the following: 1. Is https://data-development.appattest.apple.com the correct endpoint for key attestation in a development environment? 2. Should this endpoint accept CBOR-encoded payloads, or is it only for JSON-based assertion validation? 3. Is there a current official Apple documentation that lists: • the correct URLs for key attestation and assertion validation (production and development), • or any server-side example code (e.g., Java, Python) for handling attestation/validation on the backend? So far, I couldn’t find an official document that explicitly describes the expected HTTP endpoints for these operations. If there’s a newer guide or updated API reference, I’d appreciate a link. Thanks in advance for your help.
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258
May ’25
Zero Trust - macOS Tahoe 26.0 (
Hi all, I've on high alert after hearing about the security concerns with npm. Full disclosure, I'm new to computer and network architecture, however, as someone who is on high alert for aplications exfiltrating data or poisioning my on-device machine learning models — I've seen some things I can't fully explain and I'm hoping the community can help. I ran the code odutil show all and I was wondering why certain node names are hidden in my system and when I use the directory utility, I can't use my computer login and password to authenticate to see the users? Am I being locked out of seeing my own system? I'm trying to dig to see if a root kit was installed on my device. Does anyone know what the users and groups in the directory utility are? Who is "nobody" and who is "Unknown user"? I'll probably have a lot more questions about this suspicious files I've seen on my device. Does anyone else's device download machine learning model payloads from the internet without notifying the user (even through a firewall, no startup applications?). I've also tried deleting applications I no longer need anymore and my "system" makes them re-appear.... what?
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503
Sep ’25
DCDevice.current.generateToken Is it safe to cache tokens for less than 1s ?
We have a crash on DCDevice.current.isSupported We want to try to make a serial queue to generate tokens but the side effect would be the same token would be used on multiple server API requests that are made within a few ms of each other? Is this safe or will the Apple server immediately reject the same token being reused? Can you share how long tokens are safe to use for? Here is the code we want to try final actor DeviceTokenController: NSObject { static var shared: DeviceTokenController = .init() private var tokenGenerationTask: Task<Data?, Never>? var ephemeralDeviceToken: Data? { get async { // Re-using the token for short periods of time if let existingTask = tokenGenerationTask { return await existingTask.value } let task = Task<Data?, Never> { guard DCDevice.current.isSupported else { return nil } do { return try await DCDevice.current.generateToken() } catch { Log("Failed to generate ephemeral device token", error) return nil } } tokenGenerationTask = task let result = await task.value tokenGenerationTask = nil return result } } }
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649
Jul ’25
Empty userID for cross-platform attestation with Android
I've come across strange behavior with the userID property on the returned credential from a passkey attestation. When performing a cross-device passkey assertion between iOS and Android by scanning the generated QR code on my iPhone with an Android device the returned credential object contains an empty userID. This does not happen when performing an on device or cross-device assertion using two iPhones. Is this expected behavior, or is there something I'm missing here? I couldn't find any more information on this in the documentation. iOS Version: 26.0.1, Android Version: 13
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456
Oct ’25
Different PRF output when using platform or cross-platform authentication attachement
Hello, I am using the prf extension for passkeys that is available since ios 18 and macos15. I am using a fixed, hardcoded prf input when creating or geting the credentials. After creating a passkey, i try to get the credentials and retrieve the prf output, which works great, but i am getting different prf outputs for the same credential and same prf input used in the following scenarios: Logging in directly (platform authenticator) on my macbook/iphone/ipad i get "prf output X" consistently for the 3 devices When i use my iphone/ipad to scan the qr code on my macbook (cross-platform authenticator) i get "prf output Y" consistently with both my ipad and iphone. Is this intended? Is there a way to get deterministic prf output for both platform and cross-platform auth attachements while using the same credential and prf input?
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1.3k
Apr ’26
why prepareInterfaceToProvideCredential does call
we develop extension "Autofill Credential Provider" function for passkey. 1.first step registe passkey 2.second step authenticate with passkey step 1 &amp; step 2 has finished and run success with provideCredentialWithoutUserInteraction. But we want to prepare our interface for use to input password and select passkey what the want. however the func prepareInterfaceToProvideCredential in ASCredentialProviderViewController does call? what i missed? how can i do it?
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197
Jul ’25
Question: Best Practice for Storing API Keys in iOS Apps (RevenueCat, PostHog, AWS Rekognition, etc.)
Hi everyone, I’m looking for clarification on best practices for storing API keys in an iOS app — for example, keys used with RevenueCat, PostHog, AWS Rekognition, barcode scanners, and similar third-party services. I understand that hard-coding API keys directly in the app’s source code is a bad idea, since they can be extracted from the binary. However, using a .plist file doesn’t seem secure either, as it’s still bundled with the app and can be inspected. I’m wondering: What are Apple’s recommended approaches for managing these kinds of keys? Does Xcode Cloud offer a built-in or best-practice method for securely injecting environment variables or secrets at build time? Would using an external service like AWS Secrets Manager or another server-side solution make sense for this use case? Any insights or examples of how others are handling this securely within Apple’s ecosystem would be greatly appreciated. Thanks for considering my questions! — Paul
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Oct ’25
Title: Sporadical - Permissions Not Cleared After App Uninstallation on iOS18
Title: Sporadical - Permissions Not Cleared After App Uninstallation on iOS18 I install and launch my private MAUI App I ask for example Bluetooth permissions (can be any other permission) I tap Allow button on native settings (or Don't Allow) I unistall app from real phone (we can wait for a while) I install and launch My Private MAUI App I ask for example Bluetooth permissions &lt;- here is an issue. Bluetooth is already granted, so I cannot ask for it again. Occurrence: This issue occurs inconsistently: On iOS 18.5: approximately 5 out of 10 times On iOS 17: approximately 1 out of 50 times Tested using my automated system using Appium latest. After each scenario I unistall app using: "mobile: removeApp" with bundleId
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136
Jun ’25
SecurityAgent taking focus for plugin in macOS 26.1
We have a custom SecurityAgentPlugin that is triggered by multiple authorizationdb entries. Some customers report that the SecurityAgent process takes window focus even though no UI or windows are displayed. Our plugin explicitly ignores the _securityAgent user and does not show any UI for that user. However, in macOS 26.1, it appears that the plugin still causes the SecurityAgent to take focus as soon as it is triggered. Is this a change in macOS 26.1 or a bug? Can we do anything to prevent "focus stealing"?
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5.5k
Mar ’26
Conditional create on iPhone + Safari + Passwords violates the WebAuthn spec
WebAuthn Level 3 § 5.1.3 Step 22 Item 4 states the steps a user agent MUST follow when "conditional" mediation is used in conjunction with required user verification: Let userVerification be the effective user verification requirement for credential creation, a Boolean value, as follows. If pkOptions.authenticatorSelection.userVerification is set to required If options.mediation is set to conditional and user verification cannot be collected during the ceremony, throw a ConstraintError DOMException. Let userVerification be true. On my iPhone 15 Pro Max running iOS 18.5, Safari + Passwords does not exhibit this behavior; instead an error is not reported and user verification is not performed (i.e., the UV bit is 0). Per the spec this results in a registration ceremony failure on the server which is made all the more "annoying" since the credential was created in Passwords forcing a user to then delete the credential. : If the Relying Party requires user verification for this registration, verify that the UV bit of the flags in authData is set. In contrast when I use Google Password Manager + Chrome on a Samsung Galaxy S24 running Android 15, user verification is enforced and the UV bit is 1. Either the UV bit should be 1 after enforcing user verification or an error should be thrown since user verification cannot be performed.
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581
Jul ’25
Best Practice for Keychain Storage for a C++ Plugin in a Host App (Maya)?
Hi everyone, I'm developing a C++ plugin (.bundle) for a third-party host application (Autodesk Maya) on macOS, and I'm finalizing the design for our licensing system. The plugin is distributed outside the Mac App Store. My goal is to securely store a license key in the user's Keychain. After some research, my proposed implementation is as follows: On activation, store the license data in the user's login keychain as a Generic Password (kSecClassGenericPassword) using the SecItem APIs. To ensure the plugin can access the item when loaded by Maya, I will use a specific Keychain Access Group (e.g., MY_TEAM_ID.com.mywebsite). The final .bundle will be code-signed with our company's Developer ID certificate. The signature will include an entitlements file (.entitlements) that specifies the matching keychain-access-groups permission. My understanding is that this combination of a unique Keychain Access Group and a properly signed/entitled bundle is the key to getting reliable Keychain access. This should also correctly trigger the one-time user permission prompt on first use. Does this sound like the correct and most robust approach for this scenario? Are there any common pitfalls with a plugin's Keychain access from within a host app that I should be aware of? Thanks for any feedback!
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160
Activity
Jun ’25
App Attest Issue in Production - Attestation Object Size Increased
Hi Apple Team and Community, We encountered a sudden and widespread failure related to the App Attest service on Friday, July 25, starting at around 9:22 AM UTC. After an extended investigation, our network engineers noted that the size of the attestation objects received from the attestKey call grew in size notably starting at that time. As a result, our firewall began blocking the requests from our app made to our servers with the Base64-encoded attestation objects in the payload, as these requests began triggering our firewall's max request length rule. Could Apple engineers please confirm whether there was any change rolled out by Apple at or around that time that would cause the attestation object size to increase? Can anyone else confirm seeing this? Any insights from Apple or others would be appreciated to ensure continued stability. Thanks!
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3
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455
Activity
Jul ’25
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
How to change window size of `ASWebAuthenticationSession`?
Is there a way (in code or on the OAuth2 server/webpage) to specify the desired window size when using ASWebAuthenticationSession on macOS? I haven't found anything, and we would prefer the window to be narrower. For one of our users, the window is even stretched to the full screen width which looks completely broken…
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0
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403
Activity
Aug ’25
DCError.invalidInput on generateAssertion() - Affecting Small Subset of Users
Issue Summary I'm encountering a DCError.invalidInput error when calling DCAppAttestService.shared.generateAssertion() in my App Attest implementation. This issue affects only a small subset of users - the majority of users can successfully complete both attestation and assertion flows without any issues. According to Apple Engineer feedback, there might be a small implementation issue in my code. Key Observations Success Rate: ~95% of users complete the flow successfully Failure Pattern: The remaining ~5% consistently fail at assertion generation Key Length: Logs show key length of 44 characters for both successful and failing cases Consistency: Users who experience the error tend to experience it consistently Platform: Issue observed across different iOS versions and device types Environment iOS App Attest implementation Using DCAppAttestService for both attestation and assertion Custom relying party server communication Issue affects ~5% of users consistently Key Implementation Details 1. Attestation Flow (Working) The attestation process works correctly: // Generate key and attest (successful for all users) self.attestService.generateKey { keyId, keyIdError in guard keyIdError == nil, let keyId = keyId else { return completionHandler(.failure(.dcError(keyIdError as! DCError))) } // Note: keyId length is consistently 44 characters for both successful and failing users // Attest key with Apple servers self.attestKey(keyId, clientData: clientData) { result in // ... verification with RP server // Key is successfully stored for ALL users (including those who later fail at assertion) } } 2. Assertion Flow (Failing for ~5% of Users with invalidInput) The assertion generation fails for a consistent subset of users: // Get assertion data from RP server self.assertRelyingParty.getAssertionData(kid, with: data) { result in switch result { case .success(let receivedData): let session = receivedData.session let clientData = receivedData.clientData let hash = clientData.toSHA256() // SHA256 hash of client data // THIS CALL FAILS WITH invalidInput for ~5% of users // Same keyId (44 chars) that worked for attestation self.attestService.generateAssertion(kid, clientDataHash: hash) { assertion, err in guard err == nil, let assertion = assertion else { // Error: DCError.invalidInput if let err = err as? DCError, err.code == .invalidKey { return reattestAndAssert(.invalidKey, completionHandler) } else { return completionHandler(.failure(.dcError(err as! DCError))) } } // ... verification logic } } } 3. Client Data Structure Client data JSON structure (identical for successful and failing users): // For attestation (works for all users) let clientData = ["challenge": receivedData.challenge] // For assertion (fails for ~5% of users with same structure) var clientData = ["challenge": receivedData.challenge] if let data = data { // Additional data for assertion clientData["account"] = data["account"] clientData["amount"] = data["amount"] } 4. SHA256 Hash Implementation extension Data { public func toSHA256() -> Data { return Data(SHA256.hash(data: self)) } } 5. Key Storage Implementation Using UserDefaults for key storage (works consistently for all users): private let keyStorageTag = "app-attest-keyid" func setKey(_ keyId: String) -> Result<(), KeyStorageError> { UserDefaults.standard.set(keyId, forKey: keyStorageTag) return .success(()) } func getKey() -> Result<String?, KeyStorageError> { let keyId = UserDefaults.standard.string(forKey: keyStorageTag) return .success(keyId) } Questions User-Specific Factors: Since this affects only ~5% of users consistently, could there be device-specific, iOS version-specific, or account-specific factors that cause invalidInput? Key State Validation: Is there any way to validate the state of an attested key before calling generateAssertion()? The key length (44 chars) appears normal for both successful and failing cases. Keychain vs UserDefaults: Could the issue be related to using UserDefaults instead of Keychain for key storage? Though this works for 95% of users. Race Conditions: Could there be subtle race conditions or timing issues that only affect certain users/devices? Error Recovery: Is there a recommended way to handle this error? Should we attempt re-attestation for these users? Additional Context & Debugging Attempts Consistent Failure: Users who experience this error typically experience it on every attempt Key Validation: Both successful and failing users have identical key formats (44 character strings) Device Diversity: Issue observed across different device models and iOS versions Server Logs: Our server successfully provides challenges and processes attestation for all users Re-attestation: Forcing re-attestation sometimes resolves the issue temporarily, but it often recurs The fact that 95% of users succeed with identical code suggests there might be some environmental or device-specific factor that we're not accounting for. Any insights into what could cause invalidInput for a subset of users would be invaluable.
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2
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573
Activity
Jun ’25
Keychain Sharing not working after Updating the Team ID
We are facing an issue with Keychain sharing across our apps after our Team ID was updated. Below are the steps we have already tried and the current observations: Steps we have performed so far: After our Team ID changed, we opened and re-saved all the provisioning profiles. We created a Keychain Access Group: xxxx.net.soti.mobicontrol (net.soti.mobicontrol is one bundle id of one of the app) and added it to the entitlements of all related apps. We are saving and reading certificates using this access group only. Below is a sample code snippet we are using for the query: [genericPasswordQuery setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass]; [genericPasswordQuery setObject:identifier forKey:(id)kSecAttrGeneric]; [genericPasswordQuery setObject:accessGroup forKey:(id)kSecAttrAccessGroup]; [genericPasswordQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit]; [genericPasswordQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes]; Issues we are facing: Keychain items are not being shared consistently across apps. We receive different errors at different times: Sometimes errSecDuplicateItem (-25299), even when there is no item in the Keychain. Sometimes it works in a debug build but fails in Ad Hoc / TestFlight builds. The behavior is inconsistent and unpredictable. Expectation / Clarification Needed from Apple: Are we missing any additional configuration steps after the Team ID update? Is there a known issue with Keychain Access Groups not working correctly in certain build types (Debug vs AdHoc/TestFlight)? Guidance on why we are intermittently getting -25299 and how to properly reset/re-add items in the Keychain. Any additional entitlement / provisioning profile configuration that we should double-check. Request you to please raise a support ticket with Apple Developer Technical Support including the above details, so that we can get guidance on the correct setup and resolve this issue.
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4
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0
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435
Activity
Sep ’25
Permission requirements for LAContext's canEvaluatePolicy
Hi, I am developing an app that checks if biometric authentication capabilities (Face ID and Touch ID) are available on a device. I have a few questions: Do I need to include a privacy string in my app to use the LAContext's canEvaluatePolicy function? This function checks if biometric authentication is available on the device, but does not actually trigger the authentication. From my testing, it seems like a privacy declaration is only required when using LAContext's evaluatePolicy function, which would trigger the biometric authentication. Can you confirm if this is the expected behavior across all iOS versions and iPhone models? When exactly does the biometric authentication permission pop-up appear for users - is it when calling canEvaluatePolicy or evaluatePolicy? I want to ensure my users have a seamless experience. Please let me know if you have any insights on these questions. I want to make sure I'm handling the biometric authentication functionality correctly in my app. Thank you!
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2
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0
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183
Activity
Jun ’25
MSAL framework return force authentication
Hi, We are using the MSAL library to authenticate users, with SSO authentication implemented through the Microsoft Authenticator app. The problem is that once or twice a day, a prompt for forced authentication appears, indicating that silent token acquisition is failing and resulting in a requirement for forced authentication. Below are some of the logs: ================================================= 2025-08-28 11:00:05.034 [Info] [AppDelegate.swift:121] application(:didFinishLaunchingWithOptions:) > MSAL message: TID=751353 MSAL 1.8.1 iOS 18.5 [2025-08-28 10:00:05 - EC9D1457-2D70-4878-926F-553391EBC9D3] [MSAL] Silent flow finished. Result (null), error: -51115 error domain: MSIDErrorDomain 2025-08-28 11:00:05.034 [Info] [AppDelegate.swift:121] application(:didFinishLaunchingWithOptions:) > MSAL message: TID=751353 MSAL 1.8.1 iOS 18.5 [2025-08-28 10:00:05 - EC9D1457-2D70-4878-926F-553391EBC9D3] [MSAL] acquireTokenSilent returning with error: (MSALErrorDomain, -50002) Masked(not-null) ==================================================== We initially raised this issue with Microsoft, but according to them: In the app's logs, the single one failure it contains, was when the SSO extension returned the error com.apple.AuthenticationServices.AuthorizationError, -6000 during a silent call. This error code is generated by the system framework (Apple), not by our code. It indicates that the framework encountered an unexpected internal issue before or after calling the SSO extension. MSAL returning interaction_required to the client app is the most effective way to recover from this error (as you mention, after the user selects the account the app continues working as expected). Additionally, as you also mention, the interactive call is made by switching to Authenticator (not displaying a "window" without leaving Eva Lite app), which means MSAL is not able to use the SSO extension and is using the fallback to legacy authentication. The recommended next step is for the customer to request support directly from Apple as this is an issue on their side. Additionally, the customer can also try to update to the latest iOS, in case Apple has already fixed this issue. ============================================= STEPS TO REPRODUCE There is no such steps its just that this is an enterprise application which is getting used on managed devices[iPhone 14]. The device are managed using some intune policy. Platform and Version: iOS Development Environment: Xcode 15, macOS 13.6.1 Run-time Configuration: iOS 18 Please let me know if there are any solutions to resolve this problem. Thank you.
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1
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1
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864
Activity
Sep ’25
App Attest development server (data-development.appattest.apple.com) returns 403 for CBOR attestation request
Hi, I’m currently implementing App Attest attestation validation on the development server. However, I’m receiving a 403 Forbidden response when I POST a CBOR-encoded payload to the following endpoint: curl -X POST -H "Content-Type: application/cbor" --data-binary @payload.cbor 'https://data-development.appattest.apple.com' Here’s how I’m generating the CBOR payload in Java: Map&lt;String, Object&gt; payload = new HashMap&lt;&gt;(); payload.put("attestation", attestationBytes); // byte[] from DCAppAttestService payload.put("clientDataHash", clientDataHash); // SHA-256 hash of the challenge (byte[]) payload.put("keyId", keyIdBytes); // Base64-decoded keyId (byte[]) payload.put("appId", TEAM_ID + "." + BUNDLE_ID); // e.g., "ABCDE12345.com.example.app" ObjectMapper cborMapper = new ObjectMapper(new CBORFactory()); byte[] cborBody = cborMapper.writeValueAsBytes(payload); I’m unsure whether the endpoint is rejecting the payload format or if the endpoint itself is incorrect for this stage. I’d appreciate clarification on the following: 1. Is https://data-development.appattest.apple.com the correct endpoint for key attestation in a development environment? 2. Should this endpoint accept CBOR-encoded payloads, or is it only for JSON-based assertion validation? 3. Is there a current official Apple documentation that lists: • the correct URLs for key attestation and assertion validation (production and development), • or any server-side example code (e.g., Java, Python) for handling attestation/validation on the backend? So far, I couldn’t find an official document that explicitly describes the expected HTTP endpoints for these operations. If there’s a newer guide or updated API reference, I’d appreciate a link. Thanks in advance for your help.
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0
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258
Activity
May ’25
Zero Trust - macOS Tahoe 26.0 (
Hi all, I've on high alert after hearing about the security concerns with npm. Full disclosure, I'm new to computer and network architecture, however, as someone who is on high alert for aplications exfiltrating data or poisioning my on-device machine learning models — I've seen some things I can't fully explain and I'm hoping the community can help. I ran the code odutil show all and I was wondering why certain node names are hidden in my system and when I use the directory utility, I can't use my computer login and password to authenticate to see the users? Am I being locked out of seeing my own system? I'm trying to dig to see if a root kit was installed on my device. Does anyone know what the users and groups in the directory utility are? Who is "nobody" and who is "Unknown user"? I'll probably have a lot more questions about this suspicious files I've seen on my device. Does anyone else's device download machine learning model payloads from the internet without notifying the user (even through a firewall, no startup applications?). I've also tried deleting applications I no longer need anymore and my "system" makes them re-appear.... what?
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0
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503
Activity
Sep ’25
DCDevice.current.generateToken Is it safe to cache tokens for less than 1s ?
We have a crash on DCDevice.current.isSupported We want to try to make a serial queue to generate tokens but the side effect would be the same token would be used on multiple server API requests that are made within a few ms of each other? Is this safe or will the Apple server immediately reject the same token being reused? Can you share how long tokens are safe to use for? Here is the code we want to try final actor DeviceTokenController: NSObject { static var shared: DeviceTokenController = .init() private var tokenGenerationTask: Task<Data?, Never>? var ephemeralDeviceToken: Data? { get async { // Re-using the token for short periods of time if let existingTask = tokenGenerationTask { return await existingTask.value } let task = Task<Data?, Never> { guard DCDevice.current.isSupported else { return nil } do { return try await DCDevice.current.generateToken() } catch { Log("Failed to generate ephemeral device token", error) return nil } } tokenGenerationTask = task let result = await task.value tokenGenerationTask = nil return result } } }
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0
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1
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649
Activity
Jul ’25
Empty userID for cross-platform attestation with Android
I've come across strange behavior with the userID property on the returned credential from a passkey attestation. When performing a cross-device passkey assertion between iOS and Android by scanning the generated QR code on my iPhone with an Android device the returned credential object contains an empty userID. This does not happen when performing an on device or cross-device assertion using two iPhones. Is this expected behavior, or is there something I'm missing here? I couldn't find any more information on this in the documentation. iOS Version: 26.0.1, Android Version: 13
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0
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456
Activity
Oct ’25
Different PRF output when using platform or cross-platform authentication attachement
Hello, I am using the prf extension for passkeys that is available since ios 18 and macos15. I am using a fixed, hardcoded prf input when creating or geting the credentials. After creating a passkey, i try to get the credentials and retrieve the prf output, which works great, but i am getting different prf outputs for the same credential and same prf input used in the following scenarios: Logging in directly (platform authenticator) on my macbook/iphone/ipad i get "prf output X" consistently for the 3 devices When i use my iphone/ipad to scan the qr code on my macbook (cross-platform authenticator) i get "prf output Y" consistently with both my ipad and iphone. Is this intended? Is there a way to get deterministic prf output for both platform and cross-platform auth attachements while using the same credential and prf input?
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16
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1.3k
Activity
Apr ’26
why prepareInterfaceToProvideCredential does call
we develop extension "Autofill Credential Provider" function for passkey. 1.first step registe passkey 2.second step authenticate with passkey step 1 &amp; step 2 has finished and run success with provideCredentialWithoutUserInteraction. But we want to prepare our interface for use to input password and select passkey what the want. however the func prepareInterfaceToProvideCredential in ASCredentialProviderViewController does call? what i missed? how can i do it?
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0
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197
Activity
Jul ’25
Question: Best Practice for Storing API Keys in iOS Apps (RevenueCat, PostHog, AWS Rekognition, etc.)
Hi everyone, I’m looking for clarification on best practices for storing API keys in an iOS app — for example, keys used with RevenueCat, PostHog, AWS Rekognition, barcode scanners, and similar third-party services. I understand that hard-coding API keys directly in the app’s source code is a bad idea, since they can be extracted from the binary. However, using a .plist file doesn’t seem secure either, as it’s still bundled with the app and can be inspected. I’m wondering: What are Apple’s recommended approaches for managing these kinds of keys? Does Xcode Cloud offer a built-in or best-practice method for securely injecting environment variables or secrets at build time? Would using an external service like AWS Secrets Manager or another server-side solution make sense for this use case? Any insights or examples of how others are handling this securely within Apple’s ecosystem would be greatly appreciated. Thanks for considering my questions! — Paul
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2
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496
Activity
Oct ’25
Title: Sporadical - Permissions Not Cleared After App Uninstallation on iOS18
Title: Sporadical - Permissions Not Cleared After App Uninstallation on iOS18 I install and launch my private MAUI App I ask for example Bluetooth permissions (can be any other permission) I tap Allow button on native settings (or Don't Allow) I unistall app from real phone (we can wait for a while) I install and launch My Private MAUI App I ask for example Bluetooth permissions &lt;- here is an issue. Bluetooth is already granted, so I cannot ask for it again. Occurrence: This issue occurs inconsistently: On iOS 18.5: approximately 5 out of 10 times On iOS 17: approximately 1 out of 50 times Tested using my automated system using Appium latest. After each scenario I unistall app using: "mobile: removeApp" with bundleId
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1
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1
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136
Activity
Jun ’25
SecurityAgent taking focus for plugin in macOS 26.1
We have a custom SecurityAgentPlugin that is triggered by multiple authorizationdb entries. Some customers report that the SecurityAgent process takes window focus even though no UI or windows are displayed. Our plugin explicitly ignores the _securityAgent user and does not show any UI for that user. However, in macOS 26.1, it appears that the plugin still causes the SecurityAgent to take focus as soon as it is triggered. Is this a change in macOS 26.1 or a bug? Can we do anything to prevent "focus stealing"?
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27
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3
Views
5.5k
Activity
Mar ’26
Conditional create on iPhone + Safari + Passwords violates the WebAuthn spec
WebAuthn Level 3 § 5.1.3 Step 22 Item 4 states the steps a user agent MUST follow when "conditional" mediation is used in conjunction with required user verification: Let userVerification be the effective user verification requirement for credential creation, a Boolean value, as follows. If pkOptions.authenticatorSelection.userVerification is set to required If options.mediation is set to conditional and user verification cannot be collected during the ceremony, throw a ConstraintError DOMException. Let userVerification be true. On my iPhone 15 Pro Max running iOS 18.5, Safari + Passwords does not exhibit this behavior; instead an error is not reported and user verification is not performed (i.e., the UV bit is 0). Per the spec this results in a registration ceremony failure on the server which is made all the more "annoying" since the credential was created in Passwords forcing a user to then delete the credential. : If the Relying Party requires user verification for this registration, verify that the UV bit of the flags in authData is set. In contrast when I use Google Password Manager + Chrome on a Samsung Galaxy S24 running Android 15, user verification is enforced and the UV bit is 1. Either the UV bit should be 1 after enforcing user verification or an error should be thrown since user verification cannot be performed.
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1
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581
Activity
Jul ’25