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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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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201
Jun ’25
Determining if a block of data was signed on the Secure Enclave
Hello, I'm exploring the Secure Enclave APIs, and I'm wondering if it's possible to "cryptographically" determine if a block of data was signed on the Secure Enclave. When I sign a block of data using the Secure Enclave (which implies using a key pair automatically generated by the enclave) and distribute the public key to others, is there any way to verify if the message was encrypted on it / its private key was generated by it? In other words, what I'm trying to achieve is to make sure that the public key hasn't been tampered with until it reaches its destination (including on-device threats, since otherwise I could've used a normal keychain item, perhaps?). For the purpose of this example, I'm not necessarily interested in figuring out if the key was signed on a certain device's enclave, but rather on any Secure Enclave. So, using something derived from the enclave's GID Key (described in the Apple Platform Security guide) would work for this.
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604
Jan ’25
AutoFill Unavailable - The developer needs to update it to work with this feature.
I have had a password autofill app extension in production for years. It still works fine. Except when the user taps a username or password textfield and selects "AutoFill" from the context menu. They are shown a modal error dialog, stating: "AutoFill Unavailable - The developer needs to update it to work with this feature." I cannot find any help on this issue. The AutoFill extension works fine when tapping the "Passwords" bar above the iOS keyboard. Any pointers would be appreciated.
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763
Mar ’25
Issue with "NSUserTrackingUsageDescription" Blocking App Update Submission
Hi everyone, I’m currently facing an issue while trying to submit an update for my app to the App Store. The review process is blocking the update due to a "Privacy - Data Use and Sharing" warning, stating that our app requests "tracking purchase history for tracking purposes." However, we have already removed this functionality and deleted the NSUserTrackingUsageDescription key from our latest build. Despite this, the warning persists, and we are unable to proceed with the update. I have already contacted Apple Support, but in the meantime, I wanted to ask the community: Has anyone else encountered this issue, and if so, how did you resolve it? Is there a way to force a refresh of privacy-related settings in App Store Connect? Are there any additional steps we need to take to completely remove this tracking flag from our app submission? Any insights or guidance would be greatly appreciated! Thanks in advance for your help.
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577
Feb ’25
"My App" would like to access data from other apps pop up
Hi All, I have a finder sync extension that passes data back to my main app. It currently writes to a plist file in my group container folder. Since updating to macOS 15, I have been getting this pop-up every time I trigger this writing to the plist after the finder sync extension loads. This is how I write to the plist from my finder sync extension: let appGroupDefaults = UserDefaults(suiteName: "group.team_id.Finder-Sync-Extension-Test-Project") let items = FIFinderSyncController.default().selectedItemURLs() DispatchQueue.main.async { let url = items?.first?.absoluteString var file = items?.first?.lastPathComponent if let defaults = appGroupDefaults{ defaults.set(url, forKey: "targetURL") defaults.synchronize() } self.showWindow(with: NSExtensionContext()) } This is how I read the plist from my main app: if let defaults = UserDefaults(suiteName: "group.team_id.Finder-Sync-Extension-Test-Project") { defaults.synchronize() if let clickedUrl = defaults.string(forKey: "targetURL") { window = NSWindow(contentRect: NSScreen.main?.frame ?? .zero, styleMask: [.miniaturizable, .closable, .resizable, .titled], backing: .buffered, defer: false) window?.title = "My App" window?.makeKeyAndOrderFront(nil) textField.stringValue = clickedUrl window?.contentView?.addSubview(textField) } } It is fine if this popup happens once and the user's choice gets remembered. I just don't want it to happen every time. Any help on if this is the correct way to pass data between the finder sync extension and the main app or on how to get macOS to remember the choice of the user would be great. Thanks, James
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530
Jan ’25
XProtect makes app hang when running an AppleScript
I now had the second user with 26.2. complaining about a hang in my app. The hang occurs when the first AppleScript for Mail is run. Here is the relevant section from the process analysis in Activity Monitor: + 2443 OSACompile (in OpenScripting) + 52 [0x1b32b30f4] + 2443 SecurityPolicyTestDescriptor (in OpenScripting) + 152 [0x1b32a2284] + 2443 _SecurityPolicyTest(char const*, void const*, unsigned long) (in OpenScripting) + 332 [0x1b32a2118] + 2443 InterpreterSecurity_ScanBuffer (in libInterpreterSecurity.dylib) + 112 [0x28c149304] + 2443 -[InterpreterSecurity scanData:withSourceURL:] (in libInterpreterSecurity.dylib) + 164 [0x28c148db4] + 2443 -[XProtectScan beginAnalysisWithFeedback:] (in XprotectFramework) + 544 [0x1d35a1e58] + 2443 -[XPMalwareEvaluation initWithData:assessmentClass:] (in XprotectFramework) + 92 [0x1d359ada4] + 2443 -[XPMalwareEvaluation initWithRuleString:withExtraRules:withURL:withData:withAssessmentClass:feedback:] (in XprotectFramework) + 36 [0x1d359b2a8] My app is correctly signed and notarised. The first user had to completely uninstall/reinstall the app and the everything worked again. Why does this happen? How can the problem be fixed?
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Implementing Password AutoFill on macOS — Looking for Guidance
Hi everyone, I'm currently working on a native macOS app (built with SwiftUI) and I'm trying to implement Password AutoFill functionality so users can use their saved credentials from Keychain or third-party password managers. I've gone through Apple's documentation, WWDC sessions, and sample code, but I've noticed that the resources primarily focus on iOS and web implementations. There's very limited guidance specifically for macOS. I've set up: Associated Domains entitlement with the webcredentials: service The apple-app-site-association file on my server TextField with .textContentType(.username) and SecureField with .textContentType(.password) However, I'm still not seeing the expected AutoFill behavior on macOS like I would on iOS. Has anyone successfully implemented Password AutoFill on a native macOS app? Are there any macOS-specific considerations or additional steps required that differ from iOS? Any guidance, sample code, or pointers to documentation I might have missed would be greatly appreciated.
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1w
Mobile apps and consent dialogue when logging in
We are using ASWebAuthenticationSession with apps on IoS to achieve SSO between apps. The IdP for authentication (OIDC) is an on-premise and trusted enterprise IdP based on one of the leading products in the market. Our problem is that the user is prompted for every login (and logouts) with a consent dialogue box: “AppName” wants to use “internal domain-name” to Sign In This allows the app and website to share information about you. Cancel Continue” I have read in various places that Apple has a concept of “Trusted domains” where you can put an “Apple certified” static web-page on the IdP. This page needs to contain specific metadata that iOS can verify. Once a user logs in successfully a few times, and if the IdP is verified as trusted, subsequent logins would not prompt the consent screen. Question: I struggle to find Apple documentation on how to go about a process that ends with this “Apple certified web-page” on our IdP”. Anyone who has experience with this process, or who can point me in some direction to find related documentation?
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501
May ’25
Authorization Plugin View Still Appears After Login on Home Screen for a Few Seconds
I am developing a custom authorization plugin for macOS, and I’ve encountered an issue where the auth plugin view remains visible on the home screen for a few seconds after login. Issue Details: After entering valid credentials, I call setResult(.allow) in my plugin to proceed with login. The authentication succeeds, and macOS starts transitioning to the home screen. However, for a few seconds after login, the authorization plugin view is still visible on the home screen before it disappears. I have observed this issue even when using Apple's sample authorization plugin. Observation: This issue occurs without an external monitor (on a single built-in display). If I manually close the plugin window inside Destroy(AuthPlugin.mechanism), then the auth plugin views do not appear on the home screen, which seems to fix the issue. However, when I do this, a gray screen appears for about a second before the desktop environment fully loads. I suspect that the gray screen appears due to the time macOS takes to fully load the home screen environment after login. Questions: Why does the authorization plugin view persist on the home screen for a few seconds after login? Is manually closing the plugin window in Destroy(AuthPlugin.mechanism) the correct way to prevent this, or is there a better approach? Is my assumption that the gray screen appears due to the home screen not being fully loaded correct? If the gray screen is caused by home screen loading, is there a system notification or event I can listen to in order to know when the home screen has fully loaded?
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391
Mar ’25
Using provision profile to access assessments triggers a keychain popup
Hello! I do know apple does not support electron, but I do not think this is an electron related issue, rather something I am doing wrong. I'd be curious to find out why the keychain login is happenning after my app has been signed with the bundleid, entitlements, and provision profile. Before using the provision profile I did not have this issue, but it is needed for assessments feature. I'm trying to ship an Electron / macOS desktop app that must run inside Automatic Assessment Configuration. The build signs and notarizes successfully, and assessment mode itself starts on Apple-arm64 machines, but every single launch shows the system dialog that asks to allow access to the "login" keychain. The dialog appears on totally fresh user accounts, so it's not tied to anything I store there. It has happened ever since I have added the provision profile to the electron builder to finally test assessment out. entitlements.inherit.plist keys &lt;key&gt;com.apple.security.cs.allow-jit&lt;/key&gt; &lt;true/&gt; &lt;key&gt;com.apple.security.cs.allow-unsigned-executable-memory&lt;/key&gt; &lt;true/&gt; entitlements.plist keys: &lt;key&gt;com.apple.security.cs.allow-jit&lt;/key&gt; &lt;true/&gt; &lt;key&gt;com.apple.security.cs.allow-unsigned-executable-memory&lt;/key&gt; &lt;true/&gt; &lt;key&gt;com.apple.developer.automatic-assessment-configuration&lt;/key&gt; &lt;true/&gt; I'm honestly not sure whether the keychain is expected, but I have tried a lot of entitlement combinations to get rid of It. Electron builder is doing the signing, and we manually use the notary tool to notarize but probably irrelevant. mac: { notarize: false, target: 'dir', entitlements: 'buildResources/entitlements.mac.plist', provisioningProfile: 'buildResources/xyu.provisionprofile', entitlementsInherit: 'buildResources/entitlements.mac.inherit.plist', Any lead is welcome!
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106
Jun ’25
500 error on validate_device_token endpoint since around March 4
Since around March 4, 2025 off and on, we've been receiving 500 errors back from the validate_device_token endpoint on development and production. Today (March 6) we are constantly getting 500 error back. https://api.development.devicecheck.apple.com/v1/validate_device_token This was working previously before then. No change has happened on our end since then. This is a critical piece for our infrastructure. Thanks in advance. -Matt
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1.2k
Mar ’25
Device check validation API request to apple development server failed with error code 500
Our application uses device check api to validate the device token in staging server. We are using "https://api.development.devicecheck.apple.com/v1/validate_device_token"for this.But the response is 500 internal server error. Our production build is working fine.We pointed the build to "https://api.devicecheck.apple.com/v1/validate_device_token" url.We are using the same device check key for both development and production server. Device check was working fine in development server also.Suddenly it started to failed with out making any changes in our code.
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415
Mar ’25
Authorization Plugin code signing issue
Hi. We're writing Authorization Plugin and started with NullAuthPlugin compilation. When tried to run it on VM (Sonoma 14.6, SIP enabled), we're going into the following issue: `2025-03-08 13:38:20.699503-0800 0xdcb0 Error 0x0 0 0 kernel: (AppleMobileFileIntegrity) [com.apple.MobileFileIntegrity:library_validation_failure] Library Validation failed: Rejecting '/Library/Security/SecurityAgentPlugins/NullAuthPlugin.bundle/Contents/MacOS/NullAuthPlugin' (Team ID: ABCD12EF34, platform: no) for process 'SecurityAgentHel(2094)' (Team ID: N/A, platform: yes), reason: mapping process is a platform binary, but mapped file is not' As I understand, the platform binary is the one signed with Apple signature, which indeed is unavailable for us. How can we avoid this issue and run the plugin? Perhaps we're missing some build setting requirement?
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326
Mar ’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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464
Oct ’25
Unable to change App Tracking configuration
I have reached out to support and they simply tell me they are unable to help me, first redirecting me to generic Apple support, after following up they provided the explanation that they only handle administrative tasks and to post on the forums. I am unable to change my App Tracking Transparency it provides no real error, though network traffic shows a 409 HTTP response from the backend API when trying to save. Here is a screenshot of the result when trying to save. Does anyone have any suggestions on how to get this resolved? I've commented back to the reviewers and they simply provided help documentation. I have a technical issue and am unable to get anyone to help resolve this.
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295
4w
Assistance in Implementing App Attestation
Hi, We're in the process of implementing Apple's App Integrity, but am getting stalled due to missing documents. Can anyone assist with this? We've been following https://developer.apple.com/documentation/devicecheck/validating-apps-that-connect-to-your-server to make the necessary updates, but have come up short with where the document references decoding the Attestation Object. Can we get more information here and how the decoding process work?
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123
May ’25
Proper Approach to Programmatically Determine SIP State
Hello, I have encountered several challenges related to System Integrity Protection (SIP) state detection and code signing requirements. I would like to seek clarification and guidance on the proper approach to programmatically determine the SIP state. Here are the issues I’ve encountered: XPC Code Signing Check APIs: APIs like setCodeSigningRequirement and setConnectionCodeSigningRequirement do not work when SIP disabled and that's ok given what SIP is. LaunchCodeRequirement API: When using Process.launchRequirement, the LaunchCodeRequirement API does not function anymore when SIP disabled. The IsSIPProtected requirement behaves in a way that is not clearly documented -- it appears to only apply to pre-installed Apple apps. Legacy APIs: Older APIs like SecCodeCheckValidity are likely to be non-functional, though I haven’t had the chance to validate this yet. Private API Concerns: So to mitigate those limitations I prefer my app to not even try to connect to untrusted XPC or launch untrusted Processes when SIP is disabled. The only way to determine SIP state I could find is a low-level C function csr_get_active_config. However, this function is not declared in any publicly available header file, indicating that it is a private API. Since private APIs cannot be used in App Store-distributed apps and are best avoided for Developer ID-signed apps, this does not seem like a viable solution. Given these limitations, what is the recommended and proper approach to programmatically determine the SIP state in a macOS application? Any insights or guidance would be greatly appreciated. Thank you!
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151
May ’25