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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357
Jun ’25
Login Keychain Access Autmation
I have been trying to find a way to be able to sign some data with private key of an identity in login keychain without raising any prompts. I am able to do this with system keychain (obviously with correct permissions and checks) but not with login keychain. It always ends up asking user for their login password. Here is how the code looks, roughly, NSDictionary *query = @{ (__bridge id)kSecClass: (__bridge id)kSecClassIdentity, (__bridge id)kSecReturnRef: @YES, (__bridge id)kSecMatchLimit: (__bridge id)kSecMatchLimitAll }; CFTypeRef result = NULL; OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)query, (CFTypeRef *)&amp;amp;result); NSArray *identities = ( NSArray *)result; SecIdentityRef identity = NULL; for (id _ident in identities) { // pick one as required } SecKeyRef privateKey = NULL; OSStatus status = SecIdentityCopyPrivateKey(identity, &amp;amp;privateKey); NSData *strData = [string dataUsingEncoding:NSUTF8StringEncoding]; unsigned char hash[CC_SHA256_DIGEST_LENGTH]; CC_SHA256(strData.bytes, (CC_LONG)strData.length, hash); NSData *digestData = [NSData dataWithBytes:hash length:CC_SHA256_DIGEST_LENGTH]; CFErrorRef cfError = NULL; NSData *signature = (__bridge_transfer NSData *)SecKeyCreateSignature(privateKey, kSecKeyAlgorithmRSASignatureDigestPKCS1v15SHA256, (__bridge CFDataRef)digestData, &amp;amp;cfError); Above code raises these system logs in console default 08:44:52.781024+0000 securityd client is valid, proceeding default 08:44:52.781172+0000 securityd code requirement check failed (-67050), client is not Apple-signed default 08:44:52.781233+0000 securityd displaying keychain prompt for /Applications/Demo.app(81692) If the key is in login keychain, is there any way to do SecKeyCreateSignature without raising prompts? What does client is not Apple-signed mean? PS: Identities are pre-installed either manually or via some device management solution, the application is not installing them.
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170
Apr ’25
Application is not able to access any keychain info on application launch post device reboot
Before device Reboot: Here no issue from keychain. 2025-06-17 11:18:17.956334 +0530 WAVE PTX [DB_ENCRYPTION] Key successfully retrieved from the Keychain default When device is in reboot and locked (Keychain access is set to FirstUnlock) App got woken up in background SEEMS(NOT SURE) DEVICE STILL IN LOCKED STARE IF YES THEN WHICH IS EXPECTED 2025-06-17 12:12:30.036184 +0530 WAVE PTX <ALA_ERROR>: [OS-CCF] [DB_ENCRYPTION] Error while retriving Private key -25308 default 2025-06-17 12:15:28.914700 +0530 WAVE PTX <ALA_ERROR> [DB_ENCRYPTION] Error retrieving key from the Keychain: -25300 default —————————————————— And as per logs, here user has launch the application post unlock and application never got the keychain access here also. HERE STILL HAS ISSUE WITH KEYCHAIN ACCESS. 2025-06-17 12:52:55.640976 +0530 WAVE PTX DEBUG : willFinishLaunchingWithOptions default 2025-06-17 12:52:55.651371 +0530 WAVE PTX <ALA_ERROR> [DB_ENCRYPTION] Error retrieving key from the Keychain: -25300 default
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190
Jul ’25
Clang warning about 'xar_open' API deprecation in macOS 12.0. How to address/replace with a more approprite API?
Hello! We have code that extracts macOS Installer package (.pkg, .mpkg) signature information using APIs defined in <xar/xar.h> The code opens the package using ‘xar_open’ API like this. func open(file: String) throws(XarError) { xarfile = xar_open(file, READ) if xarfile == nil { throw .fileOpenError } } This code produces a clang warning in our CI build system when built for macOS 12 and up. 'xar_open' was deprecated in macOS 12.0: xar is a deprecated file format and should not be used. Question #1: What is the appropriate / more preferred way to extract signature information from an Installer package given that xar related APIs are deprecated? We use xar APIs to validate the package signature prior to installation to prevent packagers not signed by our team ID from being installed. Question #2: “xar is a deprecated file format and should not be used.”. Does this phrase refer to the file format that should be avoided or the API that extract signature information? We distribute our product using Developer ID method that using pkg/mpkg formats which I believe internally follow the same structure as xar files. I hope this message does not mean we should rethink the distribution method for our products. Thank you. Filed FB FB17148233 as well.
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427
Apr ’25
Custom Authorization Plugin in Login Flow
What Has Been Implemented Replaced the default loginwindow:login with a custom authorization plugin. The plugin: Performs primary OTP authentication. Displays a custom password prompt. Validates the password using Open Directory (OD) APIs. Next Scenario was handling password change Password change is simulated via: sudo pwpolicy -u robo -setpolicy "newPasswordRequired=1" On next login: Plugin retrieves the old password. OD API returns kODErrorCredentialsPasswordChangeRequired. Triggers a custom change password window to collect and set new password. Issue Observed : After changing password: The user’s login keychain resets. Custom entries under the login keychain are removed. We have tried few solutions Using API, SecKeychainChangePassword(...) Using CLI, security set-keychain-password -o oldpwd -p newpwd ~/Library/Keychains/login.keychain-db These approaches appear to successfully change the keychain password, but: On launching Keychain Access, two password prompts appear, after authentication, Keychain Access window doesn't appear (no app visibility). Question: Is there a reliable way (API or CLI) to reset or update the user’s login keychain password from within the custom authorization plugin, so: The keychain is not reset or lost. Keychain Access works normally post-login. The password update experience is seamless. Thank you for your help and I appreciate your time and consideration
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290
Jun ’25
Certificate Trust Failing in Latest OS Releases
Trying to apply 'always trust' to certificate added to keychain using both SecItemAdd() and SecPKCS12Import() with SecTrustSettingsSetTrustSettings(). I created a launchdaemon for this purpose. AuthorizationDB is modified so that any process running in root can apply trust to certificate. let option = SecTrustSettingsResult.trustRoot.rawValue // SecTrustSettingsResult.trustAsRoot.rawValue for non-root certificates let status = SecTrustSettingsSetTrustSettings(secCertificate, SecTrustSettingsDomain.admin, [kSecTrustSettingsResult: NSNumber(value: option.rawValue)] as CFTypeRef). Above code is used to trust certificates and it was working on os upto 14.7.4. In 14.7.5 SecTrustSettingsSetTrustSettings() returns errAuthorizationInteractionNotAllowed. In 15.5 modifying authorization db with AuthorizationRightSet() itself is returning errAuthorizationDenied.Tried manually editing authorization db via terminal and same error occurred. Did apple update anything on Security framework? Any other way to trust certificates?
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185
Jun ’25
How to satisfy a custom Authorization Right?
I’m implementing a custom Authorization right with the following rule: &lt;key&gt;authenticate-user&lt;/key&gt; &lt;true/&gt; &lt;key&gt;allow-root&lt;/key&gt; &lt;true/&gt; &lt;key&gt;class&lt;/key&gt; &lt;string&gt;user&lt;/string&gt; &lt;key&gt;group&lt;/key&gt; &lt;string&gt;admin&lt;/string&gt; The currently logged-in user is a standard user, and I’ve created a hidden admin account, e.g. _hiddenadmin, which has UID≠0 but belongs to the admin group. From my Authorization Plug-in, I would like to programmatically satisfy this right using _hiddenadmin’s credentials, even though _hiddenadmin is not the logged-in user. My question: Is there a way to programmatically satisfy an authenticate-user right from an Authorization Plug-in using credentials of another (non-session) user?
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175
Jul ’25
Keychain is not getting opened after unlock when system.login.screensaver is updated to use authenticate-session-owner-or-admin
When we enable 3rd party authentication plugin using SFAuthorization window, then when user performs Lock Screen and then unlock the MAC. Now after unlock, if user tries to open Keychain Access, it is not getting opened. When trying to open Keychain Access, we are prompted for credentials but after providing the credentials Keychians are not getting opened. This is working on Sonoma 14.6.1 , but seeing this issue from macOS Sequoia onwards. Are there any suggested settings/actions to resolve this issue?
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415
Aug ’25
MacOS Authorsation Plugin and Protected System Keychain Entry.
I am developing a MacOS Authorisation Plugin, I have username and password entry items and utilising SFAuthorizationPluginView to display that. I am able to do so. Requirement is I have to store ed25519 private key in PEM format in System Keychain as I need to read this entry before login to sign a request to a remote server. I only want my authorisation plugin to access this private key in System Keychain. I am looking up resources on the internet but I could not find specific to macOS Authorisation plugin, many are specific to iOS and some point at using entitlements and app group, but I doubt that applies to macOS authorisation plugin. I'll really appreciate if some pointers are shared how can I store a private credential in System Keychain so that it can be used by only my plugin only, and this is before I have logged into the system.
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627
Mar ’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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162
Jun ’25
Can't open p12 file inside my application
I need to open p12 file from other iOS applications to import private key to my application. My app is set up to be able to open nay file with following plist &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt; &lt;plist version="1.0"&gt; &lt;dict&gt; &lt;key&gt;CFBundleDocumentTypes&lt;/key&gt; &lt;array&gt; &lt;dict&gt; &lt;key&gt;CFBundleTypeName&lt;/key&gt; &lt;string&gt;Files&lt;/string&gt; &lt;key&gt;LSHandlerRank&lt;/key&gt; &lt;string&gt;Default&lt;/string&gt; &lt;key&gt;LSItemContentTypes&lt;/key&gt; &lt;array&gt; &lt;string&gt;public.item&lt;/string&gt; &lt;string&gt;public.data&lt;/string&gt; &lt;string&gt;public.content&lt;/string&gt; &lt;/array&gt; &lt;/dict&gt; &lt;/array&gt; &lt;/dict&gt; &lt;/plist&gt; But my don't appear in share dialog from Files or Mail app for example. There are however other third party apps that can accept this file. Some of them use Share extension which I don't have, but some of them don't have it as far as I can understand. At least they don't present any UI and open apps directly. Also I've tried to specify com.rsa.pkcs-12 UTI directly but it didn't help. Also noticed that *.crt files have similar behaviour. Am I missing something about this specific file type?
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119
Apr ’25
How to Localize Biometric Prompt for SecKeyCreateSignature with Secure Enclave
I'm using Secure Enclave to generate and use a private key like this: let access = SecAccessControlCreateWithFlags(nil, kSecAttrAccessibleWhenUnlockedThisDeviceOnly, [.privateKeyUsage, .biometryAny], nil) let attributes: [String: Any] = [ kSecAttrKeyType as String: kSecAttrKeyTypeECSECPrimeRandom, kSecAttrKeySizeInBits as String: 256, kSecAttrTokenID as String: kSecAttrTokenIDSecureEnclave, kSecAttrAccessControl as String: access as Any, kSecAttrApplicationTag as String: "com.example.key".data(using: .utf8)!, kSecReturnRef as String: true ] let privateKey = SecKeyCreateRandomKey(attributes as CFDictionary, nil) Later, I use this key to sign a message: let signature = SecKeyCreateSignature(privateKey, .ecdsaSignatureMessageX962SHA256, dataToSign as CFData, nil) This prompts for biometric authentication, but shows the default system text. How can I customize or localize the biometric prompt (e.g., title, description, button text) shown during SecKeyCreateSignature? Thanks!
1
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108
Apr ’25
Keychain and Local Data Loss After App Transfer Between Developer Accounts
Hello everyone, We recently transferred our iOS app from one Apple Developer account to another, and after the transfer, we encountered a serious issue where all previously stored Keychain data and the local database became inaccessible. As a result, all users are automatically logged out and lose access to their locally stored data (such as chat history) once they update to the new version signed with the new Team ID. We understand that Keychain items are tied to the App ID prefix (Team ID), which changes during an app transfer. However, we’re looking for possible workarounds or best practices to avoid user data loss. Questions: Is there any reliable method to maintain or migrate access to old Keychain data after an app transfer? Would reverting the app back to the original developer account and releasing an update from there (to persist or migrate data) before transferring it again be a viable solution? Has anyone faced a similar issue and found a practical way to handle data persistence during an app transfer? Any guidance, technical suggestions, or shared experiences would be highly appreciated. This issue is causing major impact for our users, so we’re hoping to find a safe and supported approach. Thank you, Mohammed Hassan
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313
Oct ’25
Enable Safari autofill from my password manager app
Hello, I have a password manager app and would like to help my user's to enable the Safari autofill capability. I've made the password credential extension and that is working great. I just need to help my user's enable the feature. I could point them to Settings-&gt;General-&gt;AutoFill &amp; Password and instruct them to turn the feature on. However, I've noticed that my competitors are able to present an alert directly from their app to turn the feature on (without going to settings at all). I can't find any documentation on how to do this? Thanks for your help! //Ray
2
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135
Apr ’25
Problem with Private Access Token (PAT)
Since October 3rd, I've stopped receiving responses to the Private Access Tokens challenge. I'm using this link: https://demo-issuer.private-access-tokens.fastly.com/.well-known/token-issuer-directory. I receive tokens from Fastly and return a header to the iOS app, but then I don't receive another authentication request from iOS. The user has automatic verification enabled on their phone. The problem is global and affects all my mobile app users. Has anyone encountered a similar problem and found a solution?
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2.1k
Dec ’25
SecTrustEvaluateAsyncWithError() and Certificate Transparency
For testing purposes we have code that calls SecTrustEvaluateAsyncWithError() with a trust object containing a hardcoded leaf certificate and the corresponding intermediate certificate required to form a valid chain. Because the leaf certificate has since expired we pass a date in the past via SecTrustSetVerifyDate() at wich the certificate was still valid, but trust evaluation fails: Error Domain=NSOSStatusErrorDomain Code=-67825 "“<redacted>” certificate is not standards compliant" UserInfo={NSLocalizedDescription=“<redacted>” certificate is not standards compliant, NSUnderlyingError=0x600000c282a0 {Error Domain=NSOSStatusErrorDomain Code=-67825 "Certificate 0 “<redacted>” has errors: Certificate Transparency validation required for this use;" UserInfo={NSLocalizedDescription=Certificate 0 “<redacted>” has errors: Certificate Transparency validation required for this use;}}} I know that App Transport Security enforces Certificate Transparency by default, but is there a way around that here?
4
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515
Oct ’25
SFAuthorizationPluginView and MacOS Tahoe
Testing my security agent plugin on Tahoe and find that when unlocking the screen, I now get an extra window that pops up over the SFAuthorizationPluginView that says "macOS You must enter a password to unlock the screen" with a Cancel (enabled) and OK button (disabled). See the attached photo. This is new with Tahoe. When unlocking the screen, I see the standard username and password entry view and I enter my password and click OK. That is when this new view appears. I can only click cancel so there is no way to complete authenticating.
9
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877
Sep ’25
How to implement the "Set Up Codes In" feature
Hello, I have a password manager app and have noticed a new feature in AutoFill &amp; Passwords called "Set Up Codes In". I see that my competitors have been able to implement this feature but cannot find any documentation on how to do this. How can I make it so my app can support this feature. Any help to pointing me to the documentation or otherwise would be greatly appreciated. Thanks! //Ray
2
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112
Apr ’25