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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mTLS : Guidance on Generating SecIdentity with Existing Private Key and Certificate
Hello, I am currently working on iOS application development using Swift, targeting iOS 17 and above, and need to implement mTLS for network connections. In the registration API flow, the app generates a private key and CSR on the device, sends the CSR to the server (via the registration API), and receives back the signed client certificate (CRT) along with the intermediate/CA certificate. These certificates are then imported on the device. The challenge I am facing is pairing the received CRT with the previously generated private key in order to create a SecIdentity. Could you please suggest the correct approach to generate a SecIdentity in this scenario? If there are any sample code snippets, WWDC videos, or documentation references available, I would greatly appreciate it if you could share them. Thank you for your guidance.
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229
Aug ’25
Something odd with Endpoint Security & was_mapped_writable
I'm seeing some odd behavior which may be a bug. I've broken it down to a least common denominator to reproduce it. But maybe I'm doing something wrong. I am opening a file read-write. I'm then mapping the file read-only and private: void* pointer = mmap(NULL, 17, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0); I then unmap the memory and close the file. After the close, eslogger shows me this: {"close":{"modified":false,[...],"was_mapped_writable":false}} Which makes sense. I then change the mmap statement to: void* pointer = mmap(NULL, 17, PROT_READ, MAP_FILE | MAP_SHARED, fd, 0); I run the new code and and the close looks like: {"close":{"modified":false, [....], "was_mapped_writable":true}} Which also makes sense. I then run the original again (ie, with MAP_PRIVATE vs. MAP_SHARED) and the close looks like: {"close":{"modified":false,"was_mapped_writable":true,[...]} Which doesn't appear to be correct. Now if I just open and close the file (again, read-write) and don't mmap anything the close still shows: {"close":{ [...], "was_mapped_writable":true,"modified":false}} And the same is true if I open the file read-only. It will remain that way until I delete the file. If I recreate the file and try again, everything is good until I map it MAP_SHARED. I tried this with macOS 13.6.7 and macOS 15.0.1.
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768
Oct ’25
Crashing in sandbox-exec (FB16964888)
Why are we doing this nonsense? We want to be able to run builds in a sandbox such that they can only see the paths they are intended to depend on, to improve reproducibility. With builds with a very large number of dependencies, there's a very large number of paths added to the sandbox, and it breaks things inside libsandbox. Either it hits some sandbox length limit (sandbox-exec: pattern serialization length 66460 exceeds maximum (65535), Nix issue #4119, worked around: Nix PR 12570), or it hits an assert (this report; also Nix issue #2311). The other options for sandboxing on macOS are not viable; we acknowledge sandbox-exec and sandbox_init_with_parameters are deprecated; App Sandbox is inapplicable because we aren't an app. Our use case is closer to a browser, and all the browsers use libsandbox internally. We could possibly use SystemExtension or a particularly diabolical use of Virtualization.framework, but the former API requires notarization which is close to a no-go for our use case as open source software: it is nearly impossible to develop the software on one's own computer, and it would require us to ship a binary blob (and have the build processes to produce one in infrastructure completely dissimilar to what we use today); it also requires a bunch of engineering time. Today, we can pretend that code signing/notarization doesn't exist and that we are writing an old-school Unix daemon, because we are one. The latter is absolutely diabolical and hard to implement. See this saga about the bug we are facing: Nix issue #4119, Nix issue #2311, etc. What is going wrong I can't attach the file fail.sb as it is too large (you can view the failing test case at Lix's gerrit, CL 2870) and run this: $ sandbox-exec -D _GLOBAL_TMP_DIR=/tmp -f fail.sb /bin/sh Assertion failed: (diff <= INSTR_JUMP_NE_MAX_LENGTH), function push_jne_instr, file serialize.c, line 240. zsh: abort sandbox-exec -D _GLOBAL_TMP_DIR=/tmp -f fail.sb /bin/sh Or a stacktrace: stacktrace.txt Credits Full credits to Jade Lovelace (Lix) for writing the above text and filing a bug. This is submitted under FB16964888
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204
Mar ’25
Understanding deep sleep
Hi Team, We are trying to understand deep sleep behaviour, can you please help us clarifying on the below questions: When will we configure Hibernate 25, is it valid for M series MacBooks? Is Hibernate 25 called deep sleep mode? What are the settings I need to do on Mac, to make my Mac go in to deep sleep? When awakening from deep sleep , what would be macOS system behaviour? If we have custom SFAuthorization plug in at system.login.screensaver, what would be the behaviour with deep sleep?
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748
Sep ’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 <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>CFBundleDocumentTypes</key> <array> <dict> <key>CFBundleTypeName</key> <string>Files</string> <key>LSHandlerRank</key> <string>Default</string> <key>LSItemContentTypes</key> <array> <string>public.item</string> <string>public.data</string> <string>public.content</string> </array> </dict> </array> </dict> </plist> 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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118
Apr ’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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352
Jun ’25
Unsandboxed app can't modify other app
I work for Brave, a browser with ~80M users. We want to introduce a new system for automatic updates called Omaha 4 (O4). It's the same system that powers automatic updates in Chrome. O4 runs as a separate application on users' systems. For Chrome, this works as follows: An app called GoogleUpdater.app regularly checks for updates in the background. When a new version is found, then GoogleUpdater.app installs it into Chrome's installation directory /Applications/Google Chrome.app. But consider what this means: A separate application, GoogleUpdater.app, is able to modify Google Chrome.app. This is especially surprising because, for example, the built-in Terminal.app is not able to modify Google Chrome.app. Here's how you can check this for yourself: (Re-)install Chrome with its DMG installer. Run the following command in Terminal: mkdir /Applications/Google\ Chrome.app/test. This works. Undo the command: rm -rf /Applications/Google\ Chrome.app/test Start Chrome and close it again. mkdir /Applications/Google\ Chrome.app/test now fails with "Operation not permitted". (These steps assume that Terminal does not have Full Disk Access and System Integrity Protection is enabled.) In other words, once Chrome was started at least once, another application (Terminal in this case) is no longer allowed to modify it. But at the same time, GoogleUpdater.app is able to modify Chrome. It regularly applies updates to the browser. For each update, this process begins with an mkdir call similarly to the one shown above. How is this possible? What is it in macOS that lets GoogleUpdater.app modify Chrome, but not another app such as Terminal? Note that Terminal is not sandboxed. I've checked that it's not related to codesigning or notarization issues. In our case, the main application (Brave) and the updater (BraveUpdater) are signed and notarized with the same certificate and have equivalent requirements, entitlements and provisioning profiles as Chrome and GoogleUpdater. The error that shows up in the Console for the disallowed mkdir call is: kernel (Sandbox) System Policy: mkdir(8917) deny(1) file-write-create /Applications/Google Chrome.app/foo (It's a similar error when BraveUpdater tries to install a new version into /Applications/Brave Browser.app.) The error goes away when I disable System Integrity Protection. But of course, we cannot ask users to do that. Any help would be greatly appreciated.
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300
May ’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
API: SecPKCS12Import; error code: -25264; error message: MAC verification failed during PKCS12 import (wrong password?)
Problem Statement: Pre-requisite is to generate a PKCS#12 file using openssl 3.x or above. Note: I have created a sample cert, but unable to upload it to this thread. Let me know if there is a different way I can upload. When trying to import a p12 certificate (generated using openssl 3.x) using SecPKCS12Import on MacOS (tried on Ventura, Sonoma, Sequoia). It is failing with the error code: -25264 and error message: MAC verification failed during PKCS12 import (wrong password?). I have tried importing in multiple ways through, Security Framework API (SecPKCS12Import) CLI (security import &lt;cert_name&gt; -k ~/Library/Keychains/login.keychain -P "&lt;password&gt;”) Drag and drop in to the Keychain Application All of them fail to import the p12 cert. RCA: The issues seems to be due to the difference in the MAC algorithm. The MAC algorithm used in the modern certs (by OpenSSL3 is SHA-256) which is not supported by the APPLE’s Security Framework. The keychain seems to be expecting the MAC algorithm to be SHA-1. Workaround: The current workaround is to convert the modern p12 cert to a legacy format (using openssl legacy provider which uses openssl 1.1.x consisting of insecure algorithms) which the SecPKCS12Import API understands. I have created a sample code using references from another similar thread (https://developer.apple.com/forums/thread/723242) from 2023. The steps to compile and execute the sample is mentioned in the same file. PFA the sample code by the name “pkcs12_modern_to_legacy_converter.cpp”. Also PFA a sample certificate which will help reproduce the issue by the name “modern_certificate.p12” whose password is “export”. Questions: Is there a fix on this issue? If yes, pls guide me through it; else, is it expected to be fixed in the future releases? Is there a different way to import the p12 cert which is resistant to the issue? This issue also poses a security concerns on using outdated cryptographic algorithms. Kindly share your thoughts. pkcs12_modern_to_legacy_converter.cpp
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Apr ’25
Submission Rejected: Guideline 5.1.1 - Legal - Privacy - Data Collection and Storage
Hello Experts, I am in need of your help with this feedback from the App Reviewer. Issue Description: One or more purpose strings in the app do not sufficiently explain the use of protected resources. Purpose strings must clearly and completely describe the app's use of data and, in most cases, provide an example of how the data will be used. Next Steps: Update the location purpose string to explain how the app will use the requested information and provide a specific example of how the data will be used. See the attached screenshot. Resources: Purpose strings must clearly describe how an app uses the ability, data, or resource. The following are hypothetical examples of unclear purpose strings that would not pass review: "App would like to access your Contacts" "App needs microphone access" Feedback #2 "Regarding 5.1.1, we understand why your app needs access to location. However, the permission request alert does not sufficiently explain this to your users before accessing the location. To resolve this issue, it would be appropriate to revise the location permission request, specify why your app needs access, and provide an example of how your app will use the user's data. To learn more about purpose string requirements, watch a video from App Review with tips for writing clear purpose strings. We look forward to reviewing your app once the appropriate changes have been made." May I know how can I update my purpose string? I appealed on the first feedback by explaining what is the purpose of it but got the Feedback #2. TYIA!!
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254
Jun ’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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288
Jun ’25
AES Decryption
Having trouble decrypting a string using an encryption key and an IV. var key: String var iv: String func decryptData(_ encryptedText: String) -> String? { if let textData = Data(base64Encoded: iv + encryptedText) { do { let sealedBox = try AES.GCM.SealedBox(combined: textData) let key = SymmetricKey(data: key.data(using: .utf8)!) let decryptedData = try AES.GCM.open(sealedBox, using: key) return String(data: decryptedData, encoding: .utf8) } catch { print("Decryption failed: \(error)") return nil } } return nil } Proper coding choices aside (I'm just trying anything at this point,) the main problem is opening the SealedBox. If I go to an online decryption site, I can paste in my encrypted text, the encryption key, and the IV as plain text and I can encrypt and decrypt just fine. But I can't seem to get the right combo in my Swift code. I don't have a "tag" even though I'm using the combined option. How can I make this work when all I will be receiving is the encrypted text, the encryption key, and the IV. (the encryption key is 256 bits) Try an AES site with a key of 32 digits and an IV of 16 digits and text of your choice. Use the encrypted version of the text and then the key and IV in my code and you'll see the problem. I can make the SealedBox but I can't open it to get the decrypted data. So I'm not combining the right things the right way. Anyone notice the problem?
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443
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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161
Jun ’25
DisableFDEAutoLogin and SFAuthorizationPluginView
Hi, I have a set of plugins which are registered for login. One of them is a custom ui view for the login screen. The scenario: 1.DisableFDEAutoLogin is false. 2.The User logs in to the file vault login screen. 3.The security plugins are activated, and working. 4.We get any kind of an error from the plugins, and therefore the login fails. 5.We get a native login screen, after the denial of authorization. 6.In case that DisableFDEAutoLogin is true, I do get the custom login screen, after the file vault login. My question: Why dont I see the custom login screen, after the auto login fails? Cheers Sivan
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787
Sep ’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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373
Mar ’25
Whether non-Apple Store mac apps can use passkey?
Our desktop app for macos will be released in 2 channels appstore dmg package on our official website for users to download and install Now when we debug with passkey, we find that the package name of the appstore can normally arouse passkey, but the package name of the non-App Store can not arouse the passkey interface I need your help. Thank you
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812
Apr ’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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421
Apr ’25