General:
Forums topic: Privacy & Security
Apple Platform Security support document
Developer > Security
Enabling enhanced security for your app documentation article
Creating enhanced security helper extensions documentation article
Security Audit Thoughts forums post
Cryptography:
Forums tags: Security, Apple CryptoKit
Security framework documentation
Apple CryptoKit framework documentation
Common Crypto man pages — For the full list of pages, run:
% man -k 3cc
For more information about man pages, see Reading UNIX Manual Pages.
On Cryptographic Key Formats forums post
SecItem attributes for keys forums post
CryptoCompatibility sample code
Keychain:
Forums tags: Security
Security > Keychain Items documentation
TN3137 On Mac keychain APIs and implementations
SecItem Fundamentals forums post
SecItem Pitfalls and Best Practices forums post
Investigating hard-to-reproduce keychain problems forums post
App ID Prefix Change and Keychain Access forums post
Smart cards and other secure tokens:
Forums tag: CryptoTokenKit
CryptoTokenKit framework documentation
Mac-specific resources:
Forums tags: Security Foundation, Security Interface
Security Foundation framework documentation
Security Interface framework documentation
BSD Privilege Escalation on macOS
Related:
Networking Resources — This covers high-level network security, including HTTPS and TLS.
Network Extension Resources — This covers low-level network security, including VPN and content filters.
Code Signing Resources
Notarisation Resources
Trusted Execution Resources — This includes Gatekeeper.
App Sandbox Resources
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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Topic:
Privacy & Security
SubTopic:
General
I regularly help developers with keychain problems, both here on DevForums and for my Day Job™ in DTS. Over the years I’ve learnt a lot about the API, including many pitfalls and best practices. This post is my attempt to collect that experience in one place.
If you have questions or comments about any of this, put them in a new thread and apply the Security tag so that I see it.
Share and Enjoy
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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
SecItem: Pitfalls and Best Practices
It’s just four functions, how hard can it be?
The SecItem API seems very simple. After all, it only has four function calls, how hard can it be? In reality, things are not that easy. Various factors contribute to making this API much trickier than it might seem at first glance.
This post explains some of the keychain’s pitfalls and then goes on to explain various best practices. Before reading this, make sure you understand the fundamentals by reading its companion post, SecItem: Fundamentals.
Pitfalls
Lets start with some common pitfalls.
Queries and Uniqueness Constraints
The relationship between query dictionaries and uniqueness constraints is a major source of problems with the keychain API. Consider code like this:
var copyResult: CFTypeRef? = nil
let query = [
kSecClass: kSecClassGenericPassword,
kSecAttrService: "AYS",
kSecAttrAccount: "mrgumby",
kSecAttrGeneric: Data("SecItemHints".utf8),
] as NSMutableDictionary
let err = SecItemCopyMatching(query, ©Result)
if err == errSecItemNotFound {
query[kSecValueData] = Data("opendoor".utf8)
let err2 = SecItemAdd(query, nil)
if err2 == errSecDuplicateItem {
fatalError("… can you get here? …")
}
}
Can you get to the fatal error?
At first glance this might not seem possible because you’ve run your query and it’s returned errSecItemNotFound. However, the fatal error is possible because the query contains an attribute, kSecAttrGeneric, that does not contribute to the uniqueness. If the keychain contains a generic password whose service (kSecAttrService) and account (kSecAttrAccount) attributes match those supplied but whose generic (kSecAttrGeneric) attribute does not, the SecItemCopyMatching calls will return errSecItemNotFound. However, for a generic password item, of the attributes shown here, only the service and account attributes are included in the uniqueness constraint. If you try to add an item where those attributes match an existing item, the add will fail with errSecDuplicateItem even though the value of the generic attribute is different.
The take-home point is that that you should study the attributes that contribute to uniqueness and use them in a way that’s aligned with your view of uniqueness. See the Uniqueness section of SecItem: Fundamentals for a link to the relevant documentation.
Erroneous Attributes
Each keychain item class supports its own specific set of attributes. For information about the attributes supported by a given class, see SecItem: Fundamentals.
I regularly see folks use attributes that aren’t supported by the class they’re working with. For example, the kSecAttrApplicationTag attribute is only supported for key items (kSecClassKey). Using it with a certificate item (kSecClassCertificate) will cause, at best, a runtime error and, at worst, mysterious bugs.
This is an easy mistake to make because:
The ‘parameter block’ nature of the SecItem API means that the compiler won’t complain if you use an erroneous attribute.
On macOS, the shim that connects to the file-based keychain ignores unsupported attributes.
Imagine you want to store a certificate for a particular user. You might write code like this:
let err = SecItemAdd([
kSecClass: kSecClassCertificate,
kSecAttrApplicationTag: Data(name.utf8),
kSecValueRef: cert,
] as NSDictionary, nil)
The goal is to store the user’s name in the kSecAttrApplicationTag attribute so that you can get back their certificate with code like this:
let err = SecItemCopyMatching([
kSecClass: kSecClassCertificate,
kSecAttrApplicationTag: Data(name.utf8),
kSecReturnRef: true,
] as NSDictionary, ©Result)
On iOS, and with the data protection keychain on macOS, both calls will fail with errSecNoSuchAttr. That makes sense, because the kSecAttrApplicationTag attribute is not supported for certificate items. Unfortunately, the macOS shim that connects the SecItem API to the file-based keychain ignores extraneous attributes. This results in some very bad behaviour:
SecItemAdd works, ignoring kSecAttrApplicationTag.
SecItemCopyMatching ignores kSecAttrApplicationTag, returning the first certificate that it finds.
If you only test with a single user, everything seems to work. But, later on, when you try your code with multiple users, you might get back the wrong result depending on the which certificate the SecItemCopyMatching call happens to discover first.
Ouch!
Context Matters
Some properties change behaviour based on the context. The value type properties are the biggest offender here, as discussed in the Value Type Subtleties section of SecItem: Fundamentals. However, there are others.
The one that’s bitten me is kSecMatchLimit:
In a query and return dictionary its default value is kSecMatchLimitOne. If you don’t supply a value for kSecMatchLimit, SecItemCopyMatching returns at most one item that matches your query.
In a pure query dictionary its default value is kSecMatchLimitAll. For example, if you don’t supply a value for kSecMatchLimit, SecItemDelete will delete all items that match your query. This is a lesson that, once learnt, is never forgotten!
Note Although this only applies to the data protection keychain. If you’re on macOS and targeting the file-based keychain, kSecMatchLimit always defaults to kSecMatchLimitOne (r. 105800863). Fun times!
Digital Identities Aren’t Real
A digital identity is the combination of a certificate and the private key that matches the public key within that certificate. The SecItem API has a digital identity keychain item class, namely kSecClassIdentity. However, the keychain does not store digital identities. When you add a digital identity to the keychain, the system stores its components, the certificate and the private key, separately, using kSecClassCertificate and kSecClassKey respectively.
This has a number of non-obvious effects:
Adding a certificate can ‘add’ a digital identity. If the new certificate happens to match a private key that’s already in the keychain, the keychain treats that pair as a digital identity.
Likewise when you add a private key.
Similarly, removing a certificate or private key can ‘remove’ a digital identity.
Adding a digital identity will either add a private key, or a certificate, or both, depending on what’s already in the keychain.
Removing a digital identity removes its certificate. It might also remove the private key, depending on whether that private key is used by a different digital identity.
The system forms a digital identity by matching the kSecAttrApplicationLabel (klbl) attribute of the private key with the kSecAttrPublicKeyHash (pkhh) attribute of the certificate. If you add both items to the keychain and the system doesn’t form an identity, check the value of these attributes.
For more information the key attributes, see SecItem attributes for keys.
Keys Aren’t Stored in the Secure Enclave
Apple platforms let you protect a key with the Secure Enclave (SE). The key is then hardware bound. It can only be used by that specific SE [1].
Earlier versions of the Protecting keys with the Secure Enclave article implied that SE-protected keys were stored in the SE itself. This is not true, and it’s caused a lot of confusion. For example, I once asked the keychain team “How much space does the SE have available to store keys?”, a question that’s complete nonsense once you understand how this works.
In reality, SE-protected keys are stored in the standard keychain database alongside all your other keychain items. The difference is that the key is wrapped in such a way that only the SE can use it. So, the key is protected by the SE, not stored in the SE.
A while back we updated the docs to clarify this point but the confusion persists.
[1] Technically it’s that specific iteration of that specific SE. If you erase the device then the key material needed to use the key is erased and so the key becomes permanently useless. This is the sort of thing you’ll find explained in Apple Platform Security.
Careful With that Shim, Mac Developer
As explained in TN3137 On Mac keychain APIs and implementations, macOS has a shim that connects the SecItem API to either the data protection keychain or the file-based keychain depending on the nature of the request. That shim has limitations. Some of those are architectural but others are simply bugs in the shim. For some great examples, see the Investigating Complex Attributes section below.
The best way to avoid problems like this is to target the data protection keychain. If you can’t do that, try to avoid exploring the outer reaches of the SecItem API. If you encounter a case that doesn’t make sense, try that same case with the data protection keychain. If it works there but fails with the file-based keychain, please do file a bug against the shim. It’ll be in good company.
Here’s some known issues with the shim:
It ignores unsupported attributes. See Erroneous Attributes, above, for more background on that.
The shim can fan out to both the data protection and the file-based keychain. In that case it has to make a policy decision about how to handle errors. This results in some unexpected behaviour (r. 143405965). For example, if you call SecItemCopyMatching while the keychain is locked, the data protection keychain will fail with errSecInteractionNotAllowed (-25308). OTOH, it’s possible to query for the presence of items in the file-based keychain even when it’s locked. If you do that and there’s no matching item, the file-based keychain fails with errSecItemNotFound (-25300). When the shim gets these conflicting errors, it chooses to return the latter. Whether this is right or wrong depends on your perspective, but it’s certainly confusing, especially if you’re coming at this from the iOS side.
If you call SecItemDelete without specifying a match limit (kSecMatchLimit), the data protection keychain deletes all matching items, whereas the file-based keychain just deletes a single match (r. 105800863).
While these issue have all have bug numbers, there’s no guarantee that any of them will be fixed. Fixing bugs like this is tricky because of binary compatibility concerns.
Add-only Attributes
Some attributes can only be set when you add an item. These attributes are usually associated with the scope of the item. For example, to protect an item with the Secure Enclave, supply the kSecAttrAccessControl attribute to the SecItemAdd call. Once you do that, however, you can’t change the attribute. Calling SecItemUpdate with a new kSecAttrAccessControl won’t work.
Lost Keychain Items
A common complaint from developers is that a seemingly minor update to their app has caused it to lose all of its keychain items. Usually this is caused by one of two problems:
Entitlement changes
Query dictionary confusion
Access to keychain items is mediated by various entitlements, as described in Sharing access to keychain items among a collection of apps. If the two versions of your app have different entitlements, one version may not be able to ‘see’ items created by the other.
Imagine you have an app with an App ID of SKMME9E2Y8.com.example.waffle-varnisher. Version 1 of your app is signed with the keychain-access-groups entitlement set to [ SKMME9E2Y8.groupA, SKMME9E2Y8.groupB ]. That makes its keychain access group list [ SKMME9E2Y8.groupA, SKMME9E2Y8.groupB, SKMME9E2Y8.com.example.waffle-varnisher ]. If this app creates a new keychain item without specifying kSecAttrAccessGroup, the system places the item into SKMME9E2Y8.groupA. If version 2 of your app removes SKMME9E2Y8.groupA from the keychain-access-groups, it’ll no longer be able to see the keychain items created by version 1.
You’ll also see this problem if you change your App ID prefix, as described in App ID Prefix Change and Keychain Access.
IMPORTANT When checking for this problem, don’t rely on your .entitlements file. There are many steps between it and your app’s actual entitlements. Rather, run codesign to dump the entitlements of your built app:
% codesign -d --entitlements - /path/to/your.app
Lost Keychain Items, Redux
Another common cause of lost keychain items is confusion about query dictionaries, something discussed in detail in this post and SecItem: Fundamentals. If SecItemCopyMatching isn’t returning the expected item, add some test code to get all the items and their attributes. For example, to dump all the generic password items, run code like this:
func dumpGenericPasswords() throws {
let itemDicts = try secCall {
SecItemCopyMatching([
kSecClass: kSecClassGenericPassword,
kSecMatchLimit: kSecMatchLimitAll,
kSecReturnAttributes: true,
] as NSDictionary, $0)
} as! [[String: Any]]
print(itemDicts)
}
Then compare each item’s attributes against the attributes you’re looking for to see why there was no match.
Data Protection and Background Execution
Keychain items are subject to data protection. Specifically, an item may or may not be accessible depending on whether specific key material is available. For an in-depth discussion of how this works, see Apple Platform Security.
Note This section focuses on iOS but you’ll see similar effects on all Apple platforms. On macOS specifically, the contents of this section only apply to the data protection keychain.
The keychain supports three data protection levels:
kSecAttrAccessibleWhenUnlocked
kSecAttrAccessibleAfterFirstUnlock
kSecAttrAccessibleAlways
Note There are additional data protection levels, all with the ThisDeviceOnly suffix. Understanding those is not necessary to understanding this pitfall.
Each data protection level describes the lifetime of the key material needed to work with items protected in that way. Specifically:
The key material needed to work with a kSecAttrAccessibleWhenUnlocked item comes and goes as the user locks and unlocks their device.
The key material needed to work with a kSecAttrAccessibleAfterFirstUnlock item becomes available when the device is first unlocked and remains available until the device restarts.
The default data protection level is kSecAttrAccessibleWhenUnlocked. If you add an item to the keychain and don’t specify a data protection level, this is what you get [1].
To specify a data protection level when you add an item to the keychain, apply the kSecAttrAccessible attribute. Alternatively, embed the access level within a SecAccessControl object and apply that using the kSecAttrAccessControl attribute.
IMPORTANT It’s best practice to set these attributes when you add the item and then never update them. See Add-only Attributes, above, for more on that.
If you perform an operation whose data protection is incompatible with the currently available key material, that operation fails with errSecInteractionNotAllowed [2].
There are four fundamental keychain operations, discussed in the SecItem: Fundamentals, and each interacts with data protection in a different way:
Copy — If you attempt to access a keychain item whose key material is unavailable, SecItemCopyMatching fails with errSecInteractionNotAllowed. This is an obvious result; the whole point of data protection is to enforce this security policy.
Add — If you attempt to add a keychain item whose key material is unavailable, SecItemAdd fails with errSecInteractionNotAllowed. This is less obvious. The reason why this fails is that the system needs the key material to protect (by encryption) the keychain item, and it can’t do that if if that key material isn’t available.
Update — If you attempt to update a keychain item whose key material is unavailable, SecItemUpdate fails with errSecInteractionNotAllowed. This result is an obvious consequence of the previous result.
Delete — Deleting a keychain item, using SecItemDelete, doesn’t require its key material, and thus a delete will succeed when the item is otherwise unavailable.
That last point is a significant pitfall. I regularly see keychain code like this:
Read an item holding a critical user credential.
If that works, use that credential.
If it fails, delete the item and start from a ‘factory reset’ state.
The problem is that, if your code ends up running in the background unexpectedly, step 1 fails with errSecInteractionNotAllowed and you turn around and delete the user’s credential. Ouch!
Note Even if you didn’t write this code, you might have inherited it from a keychain wrapper library. See *Think Before Wrapping, below.
There are two paths forward here:
If you don’t expect this code to work in the background, check for the errSecInteractionNotAllowed error and non-destructively cancel the operation in that case.
If you expect this code to be running in the background, switch to a different data protection level.
WARNING For the second path, the most obvious fix is to move from kSecAttrAccessibleWhenUnlocked to kSecAttrAccessibleAfterFirstUnlock. However, this is not a panacea. It’s possible that your app might end up running before first unlock [3]. So, if you choose the second path, you must also make sure to follow the advice for the first path.
You can determine whether the device is unlocked using the isProtectedDataAvailable property and its associated notifications. However, it’s best not to use this property as part of your core code, because such preflighting is fundamentally racy. Rather, perform the operation and handle the error gracefully.
It might make sense to use isProtectedDataAvailable property as part of debugging, logging, and diagnostic code.
[1] For file data protection there’s an entitlement (com.apple.developer.default-data-protection) that controls the default data protection level. There’s no such entitlement for the keychain. That’s actually a good thing! In my experience the file data protection entitlement is an ongoing source of grief. See this thread if you’re curious.
[2] This might seem like an odd error but it’s actually pretty reasonable:
The operation needs some key material that’s currently unavailable.
Only a user action can provide that key material.
But the data protection keychain will never prompt the user to unlock their device.
Thus you get an error instead.
[3] iOS generally avoids running third-party code before first unlock, but there are circumstances where that can happen. The obvious legitimate example of this is a VoIP app, where the user expects their phone to ring even if they haven’t unlocked it since the last restart. There are also other less legitimate examples of this, including historical bugs that caused apps to launch in the background before first unlock.
Best Practices
With the pitfalls out of the way, let’s talk about best practices.
Less Painful Dictionaries
I look at a lot of keychain code and it’s amazing how much of it is way more painful than it needs to be. The biggest offender here is the dictionaries. Here are two tips to minimise the pain.
First, don’t use CFDictionary. It’s seriously ugly. While the SecItem API is defined in terms of CFDictionary, you don’t have to work with CFDictionary directly. Rather, use NSDictionary and take advantage of the toll-free bridge.
For example, consider this CFDictionary code:
CFTypeRef keys[4] = {
kSecClass,
kSecAttrService,
kSecMatchLimit,
kSecReturnAttributes,
};
static const int kTen = 10;
CFNumberRef ten = CFNumberCreate(NULL, kCFNumberIntType, &kTen);
CFAutorelease(ten);
CFTypeRef values[4] = {
kSecClassGenericPassword,
CFSTR("AYS"),
ten,
kCFBooleanTrue,
};
CFDictionaryRef query = CFDictionaryCreate(
NULL,
keys,
values,
4,
&kCFTypeDictionaryKeyCallBacks,
&kCFTypeDictionaryValueCallBacks
);
Note This might seem rather extreme but I’ve literally seen code like this, and worse, while helping developers.
Contrast this to the equivalent NSDictionary code:
NSDictionary * query = @{
(__bridge NSString *) kSecClass: (__bridge NSString *) kSecClassGenericPassword,
(__bridge NSString *) kSecAttrService: @"AYS",
(__bridge NSString *) kSecMatchLimit: @10,
(__bridge NSString *) kSecReturnAttributes: @YES,
};
Wow, that’s so much better.
Second, if you’re working in Swift, take advantage of its awesome ability to create NSDictionary values from Swift dictionary literals. Here’s the equivalent code in Swift:
let query = [
kSecClass: kSecClassGenericPassword,
kSecAttrService: "AYS",
kSecMatchLimit: 10,
kSecReturnAttributes: true,
] as NSDictionary
Nice!
Avoid Reusing Dictionaries
I regularly see folks reuse dictionaries for different SecItem calls. For example, they might have code like this:
var copyResult: CFTypeRef? = nil
let dict = [
kSecClass: kSecClassGenericPassword,
kSecAttrService: "AYS",
kSecAttrAccount: "mrgumby",
kSecReturnData: true,
] as NSMutableDictionary
var err = SecItemCopyMatching(dict, ©Result)
if err == errSecItemNotFound {
dict[kSecValueData] = Data("opendoor".utf8)
err = SecItemAdd(dict, nil)
}
This specific example will work, but it’s easy to spot the logic error. kSecReturnData is a return type property and it makes no sense to pass it to a SecItemAdd call whose second parameter is nil.
I’m not sure why folks do this. I think it’s because they think that constructing dictionaries is expensive. Regardless, this pattern can lead to all sorts of weird problems. For example, it’s the leading cause of the issue described in the Queries and the Uniqueness Constraints section, above.
My advice is that you use a new dictionary for each call. That prevents state from one call accidentally leaking into a subsequent call. For example, I’d rewrite the above as:
var copyResult: CFTypeRef? = nil
let query = [
kSecClass: kSecClassGenericPassword,
kSecAttrService: "AYS",
kSecAttrAccount: "mrgumby",
kSecReturnData: true,
] as NSMutableDictionary
var err = SecItemCopyMatching(query, ©Result)
if err == errSecItemNotFound {
let add = [
kSecClass: kSecClassGenericPassword,
kSecAttrService: "AYS",
kSecAttrAccount: "mrgumby",
kSecValueData: Data("opendoor".utf8),
] as NSMutableDictionary
err = SecItemAdd(add, nil)
}
It’s a bit longer, but it’s much easier to track the flow. And if you want to eliminate the repetition, use a helper function:
func makeDict() -> NSMutableDictionary {
[
kSecClass: kSecClassGenericPassword,
kSecAttrService: "AYS",
kSecAttrAccount: "mrgumby",
] as NSMutableDictionary
}
var copyResult: CFTypeRef? = nil
let query = makeDict()
query[kSecReturnData] = true
var err = SecItemCopyMatching(query, ©Result)
if err == errSecItemNotFound {
let add = makeDict()
query[kSecValueData] = Data("opendoor".utf8)
err = SecItemAdd(add, nil)
}
Think Before Wrapping
A lot of folks look at the SecItem API and immediately reach for a wrapper library. A keychain wrapper library might seem like a good idea but there are some serious downsides:
It adds another dependency to your project.
Different subsystems within your project may use different wrappers.
The wrapper can obscure the underlying API. Indeed, its entire raison d’être is to obscure the underlying API. This is problematic if things go wrong. I regularly talk to folks with hard-to-debug keychain problems and the conversation goes something like this:
Quinn: What attributes do you use in the query dictionary?
J R Developer: What’s a query dictionary?
Quinn: OK, so what error are you getting back?
J R Developer: It throws WrapperKeychainFailedError.
That’s not helpful )-:
If you do use a wrapper, make sure it has diagnostic support that includes the values passed to and from the SecItem API. Also make sure that, when it fails, it returns an error that includes the underlying keychain error code. These benefits will be particularly useful if you encounter a keychain problem that only shows up in the field.
Wrappers must choose whether to be general or specific. A general wrapper may be harder to understand than the equivalent SecItem calls, and it’ll certainly contain a lot of complex code. On the other hand, a specific wrapper may have a model of the keychain that doesn’t align with your requirements.
I recommend that you think twice before using a keychain wrapper. Personally I find the SecItem API relatively easy to call, assuming that:
I use the techniques shown in Less Painful Dictionaries, above, to avoid having to deal with CFDictionary.
I use my secCall(…) helpers to simplify error handling. For the code, see Calling Security Framework from Swift.
If you’re not prepared to take the SecItem API neat, consider writing your own wrapper, one that’s tightly focused on the requirements of your project. For example, in my VPN apps I use the wrapper from this post, which does exactly what I need in about 100 lines of code.
Prefer to Update
Of the four SecItem functions, SecItemUpdate is the most neglected. Rather than calling SecItemUpdate I regularly see folks delete and then re-add the item. This is a shame because SecItemUpdate has some important benefits:
It preserves persistent references. If you delete and then re-add the item, you get a new item with a new persistent reference.
It’s well aligned with the fundamental database nature of the keychain. It forces you to think about which attributes uniquely identify your item and which items can be updated without changing the item’s identity.
Understand These Key Attributes
Key items have a number of attributes that are similarly named, and it’s important to keep them straight. I created a cheat sheet for this, namely, SecItem attributes for keys. You wouldn’t believe how often I consult this!
Investigating Complex Attributes
Some attributes have values where the format is not obvious. For example, the kSecAttrIssuer attributed is documented as:
The corresponding value is of type CFData and contains the X.500
issuer name of a certificate.
What exactly does that mean? If I want to search the keychain for all certificates issued by a specific certificate authority, what value should I supply?
One way to figure this out is to add a certificate to the keychain, read the attributes back, and then dump the kSecAttrIssuer value. For example:
let cert: SecCertificate = …
let attrs = try secCall { SecItemAdd([
kSecValueRef: cert,
kSecReturnAttributes: true,
] as NSDictionary, $0) } as! [String: Any]
let issuer = attrs[kSecAttrIssuer as String] as! NSData
print((issuer as NSData).debugDescription)
// prints: <3110300e 06035504 030c074d 6f757365 4341310b 30090603 55040613 024742>
Those bytes represent the contents of a X.509 Name ASN.1 structure with DER encoding. This is without the outer SEQUENCE element, so if you dump it as ASN.1 you’ll get a nice dump of the first SET and then a warning about extra stuff at the end of the file:
% xxd issuer.asn1
00000000: 3110 300e 0603 5504 030c 074d 6f75 7365 1.0...U....Mouse
00000010: 4341 310b 3009 0603 5504 0613 0247 42 CA1.0...U....GB
% dumpasn1 -p issuer.asn1
SET {
SEQUENCE {
OBJECT IDENTIFIER commonName (2 5 4 3)
UTF8String 'MouseCA'
}
}
Warning: Further data follows ASN.1 data at position 18.
Note For details on the Name structure, see section 4.1.2.4 of RFC 5280.
Amusingly, if you run the same test against the file-based keychain you’ll… crash. OK, that’s not amusing. It turns out that the code above doesn’t work when targeting the file-based keychain because SecItemAdd doesn’t return a dictionary but rather an array of dictionaries (r. 21111543). Once you get past that, however, you’ll see it print:
<301f3110 300e0603 5504030c 074d6f75 73654341 310b3009 06035504 06130247 42>
Which is different! Dumping it as ASN.1 shows that it’s the full Name structure, including the outer SEQUENCE element:
% xxd issuer-file-based.asn1
00000000: 301f 3110 300e 0603 5504 030c 074d 6f75 0.1.0...U....Mou
00000010: 7365 4341 310b 3009 0603 5504 0613 0247 seCA1.0...U....G
00000020: 42 B
% dumpasn1 -p issuer-file-based.asn1
SEQUENCE {
SET {
SEQUENCE {
OBJECT IDENTIFIER commonName (2 5 4 3)
UTF8String 'MouseCA'
}
}
SET {
SEQUENCE {
OBJECT IDENTIFIER countryName (2 5 4 6)
PrintableString 'GB'
}
}
}
This difference in behaviour between the data protection and file-based keychains is a known bug (r. 26391756) but in this case it’s handy because the file-based keychain behaviour makes it easier to understand the data protection keychain behaviour.
Import, Then Add
It’s possible to import data directly into the keychain. For example, you might use this code to add a certificate:
let certData: Data = …
try secCall { SecItemAdd([
kSecClass: kSecClassCertificate,
kSecValueData: certData,
] as NSDictionary, nil)
}
However, it’s better to import the data and then add the resulting credential reference. For example:
let certData: Data = …
let cert = try secCall {
SecCertificateCreateWithData(nil, certData as NSData)
}
try secCall { SecItemAdd([
kSecValueRef: cert,
] as NSDictionary, nil)
}
There are two advantages to this:
If you get an error, you know whether the problem was with the import step or the add step.
It ensures that the resulting keychain item has the correct attributes.
This is especially important for keys. These can be packaged in a wide range of formats, so it’s vital to know whether you’re interpreting the key data correctly.
I see a lot of code that adds key data directly to the keychain. That’s understandable because, back in the day, this was the only way to import a key on iOS. Fortunately, that’s not been the case since the introduction of SecKeyCreateWithData in iOS 10 and aligned releases.
For more information about importing keys, see Importing Cryptographic Keys.
App Groups on the Mac
Sharing access to keychain items among a collection of apps explains that three entitlements determine your keychain access:
keychain-access-groups
application-identifier (com.apple.application-identifier on macOS)
com.apple.security.application-groups
In the discussion of com.apple.security.application-groups it says:
Starting in iOS 8, the array of strings given by this
entitlement also extends the list of keychain access groups.
That’s true, but it’s also potentially misleading. This affordance only works on iOS and its child platforms. It doesn’t work on macOS.
That’s because app groups work very differently on macOS than they do on iOS. For all the details, see App Groups: macOS vs iOS: Working Towards Harmony. However, the take-home point is that, when you use the data protection keychain on macOS, your keychain access group list is built from keychain-access-groups and com.apple.application-identifier.
Revision History
2025-06-29 Added the Data Protection and Background Execution section. Made other minor editorial changes.
2025-02-03 Added another specific example to the Careful With that Shim, Mac Developer section.
2025-01-29 Added somes specific examples to the Careful With that Shim, Mac Developer section.
2025-01-23 Added the Import, Then Add section.
2024-08-29 Added a discussion of identity formation to the Digital Identities Aren’t Real section.
2024-04-11 Added the App Groups on the Mac section.
2023-10-25 Added the Lost Keychain Items and Lost Keychain Items, Redux sections.
2023-09-22 Made minor editorial changes.
2023-09-12 Fixed various bugs in the revision history. Added the Erroneous Attributes section.
2023-02-22 Fixed the link to the VPNKeychain post. Corrected the name of the Context Matters section. Added the Investigating Complex Attributes section.
2023-01-28 First posted.
When presenting a cookie banner for GDPR purposes, should ATT precede the cookie banner?
It seems that showing a Cookie Banner and then showing the ATT permission prompt afterwards (if a user elects to allow cookies/tracking) would be more appropriate.
Related question: Should the “Allow Tracking” toggle for an app in system settings serve as a master switch for any granular tracking that might be managed by a 3rd party Consent Management Platform?
If ATT is intended to serve as a master switch for tracking consent, if the ATT prompt is presented before a cookie banner, should the banner even appear if a user declines tracking consent?
I’m not finding any good resources that describe this flow in detail and I’m seeing implementations all over the place on this.
Help!
Thanks!!!
With the new ios 26 update, certain numbers will be filtered into other inboxes within imessage. What numbers are classified as "known", and will not be moved into these filters. Do they need to be a contact in your phone, or if a business texts you how will that be filtered?
Topic:
Privacy & Security
SubTopic:
General
From watching the video on App Attest the answer would appear to be no, but the video is a few years old so in hope, I thought I would post this question anyway.
There's several scenarios where I would like a notification service extension to be able to use App Attest in communications with the back end(for example to send a receipt to the backend acknowledging receipt of the push, fetching an image from a url in the push payload, a few others).
Any change App Attest can be used in by a notification service extension?
冷启动后我们读文件,发现:"error_msg":"未能打开文件“FinishTasks.plist”,因为你没有查看它的权限。
是否有这些问题:
「iOS 26 iPhone 16,2 cold launch file access failure」)
核心内容:多名开发者反馈 iPhone 15 Pro(iOS 26.0/26.1)冷启动时读取 Documents 目录下的 plist 文件提示权限拒绝,切后台再切前台恢复,苹果员工回复「建议延迟文件操作至 applicationDidBecomeActive 后」。
Topic:
Privacy & Security
SubTopic:
General
I regularly help developers with keychain problems, both here on DevForums and for my Day Job™ in DTS. Many of these problems are caused by a fundamental misunderstanding of how the keychain works. This post is my attempt to explain that. I wrote it primarily so that Future Quinn™ can direct folks here rather than explain everything from scratch (-:
If you have questions or comments about any of this, put them in a new thread and apply the Security tag so that I see it.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
SecItem: Fundamentals
or How I Learned to Stop Worrying and Love the SecItem API
The SecItem API seems very simple. After all, it only has four function calls, how hard can it be? In reality, things are not that easy. Various factors contribute to making this API much trickier than it might seem at first glance.
This post explains the fundamental underpinnings of the keychain. For information about specific issues, see its companion post, SecItem: Pitfalls and Best Practices.
Keychain Documentation
Your basic starting point should be Keychain Items.
If your code runs on the Mac, also read TN3137 On Mac keychain APIs and implementations.
Read the doc comments in <Security/SecItem.h>. In many cases those doc comments contain critical tidbits.
When you read keychain documentation [1] and doc comments, keep in mind that statements specific to iOS typically apply to iPadOS, tvOS, and watchOS as well (r. 102786959). Also, they typically apply to macOS when you target the data protection keychain. Conversely, statements specific to macOS may not apply when you target the data protection keychain.
[1] Except TN3137, which is very clear about this (-:
Caveat Mac Developer
macOS supports two different keychain implementations: the original file-based keychain and the iOS-style data protection keychain.
IMPORTANT If you’re able to use the data protection keychain, do so. It’ll make your life easier. See the Careful With that Shim, Mac Developer section of SecItem: Pitfalls and Best Practices for more about this.
TN3137 On Mac keychain APIs and implementations explains this distinction. It also says:
The file-based keychain is on the road to deprecation.
This is talking about the implementation, not any specific API. The SecItem API can’t be deprecated because it works with both the data protection keychain and the file-based keychain. However, Apple has deprecated many APIs that are specific to the file-based keychain, for example, SecKeychainCreate.
TN3137 also notes that some programs, like launchd daemons, can’t use the file-based keychain. If you’re working on such a program then you don’t have to worry about the deprecation of these file-based keychain APIs. You’re already stuck with the file-based keychain implementation, so using a deprecated file-based keychain API doesn’t make things worse.
The Four Freedoms^H^H^H^H^H^H^H^H Functions
The SecItem API contains just four functions:
SecItemAdd(_:_:)
SecItemCopyMatching(_:_:)
SecItemUpdate(_:_:)
SecItemDelete(_:)
These directly map to standard SQL database operations:
SecItemAdd(_:_:) maps to INSERT.
SecItemCopyMatching(_:_:) maps to SELECT.
SecItemUpdate(_:_:) maps to UPDATE.
SecItemDelete(_:) maps to DELETE.
You can think of each keychain item class (generic password, certificate, and so on) as a separate SQL table within the database. The rows of that table are the individual keychain items for that class and the columns are the attributes of those items.
Note Except for the digital identity class, kSecClassIdentity, where the values are split across the certificate and key tables. See Digital Identities Aren’t Real in SecItem: Pitfalls and Best Practices.
This is not an accident. The data protection keychain is actually implemented as an SQLite database. If you’re curious about its structure, examine it on the Mac by pointing your favourite SQLite inspection tool — for example, the sqlite3 command-line tool — at the keychain database in ~/Library/Keychains/UUU/keychain-2.db, where UUU is a UUID.
WARNING Do not depend on the location and structure of this file. These have changed in the past and are likely to change again in the future. If you embed knowledge of them into a shipping product, it’s likely that your product will have binary compatibility problems at some point in the future. The only reason I’m mentioning them here is because I find it helpful to poke around in the file to get a better understanding of how the API works.
For information about which attributes are supported by each keychain item class — that is, what columns are in each table — see the Note box at the top of Item Attribute Keys and Values. Alternatively, look at the Attribute Key Constants doc comment in <Security/SecItem.h>.
Uniqueness
A critical part of the keychain model is uniqueness. How does the keychain determine if item A is the same as item B? It turns out that this is class dependent. For each keychain item class there is a set of attributes that form the uniqueness constraint for items of that class. That is, if you try to add item A where all of its attributes are the same as item B, the add fails with errSecDuplicateItem. For more information, see the errSecDuplicateItem page. It has lists of attributes that make up this uniqueness constraint, one for each class.
These uniqueness constraints are a major source of confusion, as discussed in the Queries and the Uniqueness Constraints section of SecItem: Pitfalls and Best Practices.
Parameter Blocks Understanding
The SecItem API is a classic ‘parameter block’ API. All of its inputs are dictionaries, and you have to know which properties to set in each dictionary to achieve your desired result. Likewise for when you read properties in output dictionaries.
There are five different property groups:
The item class property, kSecClass, determines the class of item you’re operating on: kSecClassGenericPassword, kSecClassCertificate, and so on.
The item attribute properties, like kSecAttrAccessGroup, map directly to keychain item attributes.
The search properties, like kSecMatchLimit, control how the system runs a query.
The return type properties, like kSecReturnAttributes, determine what values the query returns.
The value type properties, like kSecValueRef perform multiple duties, as explained below.
There are other properties that perform a variety of specific functions. For example, kSecUseDataProtectionKeychain tells macOS to use the data protection keychain instead of the file-based keychain. These properties are hard to describe in general; for the details, see the documentation for each such property.
Inputs
Each of the four SecItem functions take dictionary input parameters of the same type, CFDictionary, but these dictionaries are not the same. Different dictionaries support different property groups:
The first parameter of SecItemAdd(_:_:) is an add dictionary. It supports all property groups except the search properties.
The first parameter of SecItemCopyMatching(_:_:) is a query and return dictionary. It supports all property groups.
The first parameter of SecItemUpdate(_:_:) is a pure query dictionary. It supports all property groups except the return type properties.
Likewise for the only parameter of SecItemDelete(_:).
The second parameter of SecItemUpdate(_:_:) is an update dictionary. It supports the item attribute and value type property groups.
Outputs
Two of the SecItem functions, SecItemAdd(_:_:) and SecItemCopyMatching(_:_:), return values. These output parameters are of type CFTypeRef because the type of value you get back depends on the return type properties you supply in the input dictionary:
If you supply a single return type property, except kSecReturnAttributes, you get back a value appropriate for that return type.
If you supply multiple return type properties or kSecReturnAttributes, you get back a dictionary. This supports the item attribute and value type property groups. To get a non-attribute value from this dictionary, use the value type property that corresponds to its return type property. For example, if you set kSecReturnPersistentRef in the input dictionary, use kSecValuePersistentRef to get the persistent reference from the output dictionary.
In the single item case, the type of value you get back depends on the return type property and the keychain item class:
For kSecReturnData you get back the keychain item’s data. This makes most sense for password items, where the data holds the password. It also works for certificate items, where you get back the DER-encoded certificate. Using this for key items is kinda sketchy. If you want to export a key, called SecKeyCopyExternalRepresentation. Using this for digital identity items is nonsensical.
For kSecReturnRef you get back an object reference. This only works for keychain item classes that have an object representation, namely certificates, keys, and digital identities. You get back a SecCertificate, a SecKey, or a SecIdentity, respectively.
For kSecReturnPersistentRef you get back a data value that holds the persistent reference.
Value Type Subtleties
There are three properties in the value type property group:
kSecValueData
kSecValueRef
kSecValuePersistentRef
Their semantics vary based on the dictionary type.
For kSecValueData:
In an add dictionary, this is the value of the item to add. For example, when adding a generic password item (kSecClassGenericPassword), the value of this key is a Data value containing the password.
This is not supported in a query dictionary.
In an update dictionary, this is the new value for the item.
For kSecValueRef:
In add and query dictionaries, the system infers the class property and attribute properties from the supplied object. For example, if you supply a certificate object (SecCertificate, created using SecCertificateCreateWithData), the system will infer a kSecClass value of kSecClassCertificate and various attribute values, like kSecAttrSerialNumber, from that certificate object.
This is not supported in an update dictionary.
For kSecValuePersistentRef:
For query dictionaries, this uniquely identifies the item to operate on.
This is not supported in add and update dictionaries.
Revision History
2025-05-28 Expanded the Caveat Mac Developer section to cover some subtleties associated with the deprecation of the file-based keychain.
2023-09-12 Fixed various bugs in the revision history. Added a paragraph explaining how to determine which attributes are supported by each keychain item class.
2023-02-22 Made minor editorial changes.
2023-01-28 First posted.
Hi everyone,
We are using the App Attest API to securely transition users to our new system. As part of this, we store the Key ID of the attestation key for each user to verify their identity later.
However, we’ve noticed that some users are encountering the error “DCErrorInvalidKey 3” when calling generateAssertion. Importantly, the key was previously successfully attested, and generateAssertion has worked before for these users.
Our questions:
Could this error be caused by an app or iOS update?
Is it problematic to link an attestation key's Key ID directly to a user, or are there scenarios where the key might change or become invalid?
If there’s a way to mitigate this issue or recover affected users, what best practices would you recommend?
Any help or shared experiences would be greatly appreciated! Thanks in advance.
Hello,
We received a rejection on one of our IOS applications because we were doing Microsoft MSAL login through the user's browser. The representative recommended that we use Webview to do in-app logins. However when we tried to handle the custom app uri redirection (looking like myapp://auth/), Webview does not seem to send the user back to the application. Does anyone have a fix for this?
Thanks!
Topic:
Privacy & Security
SubTopic:
General
Tags:
Safari and Web
UI Frameworks
Authentication Services
WebKit
I added a feature to my app that retrieves only app settings (no personal data) from my API hosted on Cloudflare Workers. The app does not send, collect, track, or share any user data, and I do not store or process any personal information.
Technical details such as IP address, user agent, and device information may be automatically transmitted as part of the internet protocol when the request is made, but my app does not log or use them. Cloudflare may collect this information.
Question: Does this count as “data collection” for App Store Connect purposes, or can I select “No Data Collected”?
I am trying to integrate those into my app, stuck on it would not transfer to view that inside app, can someone help?
Scott
Hi Apple Devs,
For our app, we utilize passkeys for account creation (not MFA). This is mainly for user privacy, as there is 0 PII associated with passkey account creation, but it additionally also satisfies the 4.8: Login Services requirement for the App Store.
However, we're getting blocked in Apple Review. Because the AASA does not get fetched immediately upon app install, the reviewers are not able to create an account immediately via passkeys, and then they reject the build.
I'm optimistic I can mitigate the above. But even if we pass Apple Review, this is a pretty catastrophic issue for user security and experience. There are reports that 5% of users cannot create passkeys immediately (https://developer.apple.com/forums/thread/756740). That is a nontrivial amount of users, and this large of an amount distorts how app developers design onboarding and authentication flows towards less secure experiences:
App developers are incentivized to not require MFA setup on account creation because requiring it causes significant churn, which is bad for user security.
If they continue with it anyways, for mitigation, developers are essentially forced to add in copy into their app saying something along the lines of "We have no ability to force Apple to fetch the config required to continue sign up, so try again in a few minutes, you'll just have to wait."
You can't even implement a fallback method. There's no way to check if the AASA is available before launching the ASAuthorizationController so you can't mitigate a portion of users encountering an error!!
Any app that wants to use the PRF extension to encrypt core functionality (again, good for user privacy) simply cannot exist because the app simply does not work for an unspecified amount of time for a nontrivial portion of users.
It feels like a. Apple should provide a syscall API that we can call to force SWCD to verify the AASA or b. implement a config based on package name for the app store such that the installation will immediately include a verified AASA from Apple's CDN. Flicking the config on would require talking with Apple. If this existed, this entire class of error would go away.
It feels pretty shocking that there isn't a mitigation in place for this already given that it incentivizes app developers to pursue strictly less secure and less private authentication practices.
Topic:
Privacy & Security
SubTopic:
General
Tags:
Authentication Services
Universal Links
Passkeys in iCloud Keychain
Script attachment enables advanced users to create powerful workflows that start in your app. NSUserScriptTask lets you implement script attachment even if your app is sandboxed. This post explains how to set that up.
IMPORTANT Most sandboxed apps are sandboxed because they ship on the Mac App Store [1]. While I don’t work for App Review, and thus can’t make definitive statements on their behalf, I want to be clear that NSUserScriptTask is intended to be used to implement script attachment, not as a general-purpose sandbox bypass mechanism.
If you have questions or comments, please put them in a new thread. Place it in the Privacy & Security > General subtopic, and tag it with App Sandbox.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
[1] Most but not all. There are good reasons to sandbox your app even if you distribute it directly. See The Case for Sandboxing a Directly Distributed App.
Implementing Script Attachment in a Sandboxed App
Some apps support script attachment, that is, they allow a user to configure the app to run a script when a particular event occurs. For example:
A productivity app might let a user automate repetitive tasks by configuring a toolbar button to run a script.
A mail client might let a user add a script that processes incoming mail.
When adding script attachment to your app, consider whether your scripting mechanism is internal or external:
An internal script is one that only affects the state of the app.
A user script is one that operates as the user, that is, it can change the state of other apps or the system as a whole.
Supporting user scripts in a sandboxed app is a conundrum. The App Sandbox prevents your app from changing the state of other apps, but that’s exactly what your app needs to do to support user scripts.
NSUserScriptTask resolves this conundrum. Use it to run scripts that the user has placed in your app’s Script folder. Because these scripts were specifically installed by the user, their presence indicates user intent and the system runs them outside of your app’s sandbox.
Provide easy access to your app’s Script folder
Your application’s Scripts folder is hidden within ~/Library. To make it easier for the user to add scripts, add a button or menu item that uses NSWorkspace to show it in the Finder:
let scriptsDir = try FileManager.default.url(for: .applicationScriptsDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
NSWorkspace.shared.activateFileViewerSelecting([scriptsDir])
Enumerate the available scripts
To show a list of scripts to the user, enumerate the Scripts folder:
let scriptsDir = try FileManager.default.url(for: .applicationScriptsDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
let scriptURLs = try FileManager.default.contentsOfDirectory(at: scriptsDir, includingPropertiesForKeys: [.localizedNameKey])
let scriptNames = try scriptURLs.map { url in
return try url.resourceValues(forKeys: [.localizedNameKey]).localizedName!
}
This uses .localizedNameKey to get the name to display to the user. This takes care of various edge cases, for example, it removes the file name extension if it’s hidden.
Run a script
To run a script, instantiate an NSUserScriptTask object and call its execute() method:
let script = try NSUserScriptTask(url: url)
try await script.execute()
Run a script with arguments
NSUserScriptTask has three subclasses that support additional functionality depending on the type of the script.
Use the NSUserUnixTask subsclass to run a Unix script and:
Supply command-line arguments.
Connect pipes to stdin, stdout, and stderr.
Get the termination status.
Use the NSUserAppleScriptTask subclass to run an AppleScript, executing either the run handler or a custom Apple event.
Use the NSUserAutomatorTask subclass to run an Automator workflow, supplying an optional input.
To determine what type of script you have, try casting it to each of the subclasses:
let script: NSUserScriptTask = …
switch script {
case let script as NSUserUnixTask:
… use Unix-specific functionality …
case let script as NSUserAppleScriptTask:
… use AppleScript-specific functionality …
case let script as NSUserAutomatorTask:
… use Automatic-specific functionality …
default:
… use generic functionality …
}
I'm experiencing a strange issue where ASWebAuthenticationSession works perfectly when running from Xcode (both Debug and Release), but fails on TestFlight builds.
The setup:
iOS app using ASWebAuthenticationSession for OIDC login (Keycloak)
Custom URL scheme callback (myapp://)
prefersEphemeralWebBrowserSession = false
The issue:
When using iOS Keychain autofill (with Face ID/Touch ID or normal iphone pw, that auto-submits the form) -> works perfectly
When manually typing credentials and clicking the login button -> fails with white screen
When it fails, the form POST from Keycloak back to my server (/signin-oidc) never reaches the server at all. The authentication session just shows a white screen.
Reproduced on:
Multiple devices (iPhone 15 Pro, etc.)
iOS 18.x
Xcode 16.x
Multiple TestFlight testers confirmed same behavior
What I've tried:
Clearing Safari cookies/data
prefersEphemeralWebBrowserSession = true and false
Different SameSite cookie policies on server
Verified custom URL scheme is registered and works (testing myapp://test in Safari opens the app)
Why custom URL scheme instead of Universal Links:
We couldn't get Universal Links to trigger from a js redirect (window.location.href) within ASWebAuthenticationSession. Only custom URL schemes seemed to be intercepted. If there's a way to make Universal Links work in this context, without a manual user-interaction we'd be happy to try.
iOS Keychain autofill works
The only working path is iOS Keychain autofill that requires iphone-authentication and auto-submits the form. Any manual form submission fails, but only on TestFlight - not Xcode builds.
Has anyone encountered this or know a workaround?
https://developer.apple.com/documentation/apptrackingtransparency/attrackingmanager/authorizationstatus/notdetermined
Note:
Discussion
If you call ATTrackingManager.trackingAuthorizationStatus in macOS, the result is always ATTrackingManager.AuthorizationStatus.notDetermined.
So, does macOS support getting ATT?
Hi Apple Developer Team,
I am encountering an issue with the “Sign in with Apple” feature. While implementing this functionality in my dotnet application, I noticed that the user’s first name and last name are not being returned, even though I have explicitly requested the name scope. However, the email and other requested information are returned successfully.
Here are the details of my implementation: 1. Scope Requested: name, email 2. Response Received: Email and other data are present, but fullName is missing or null. 3. Expected Behavior: I expected to receive the user’s first and last name as per the fullName scope.
I have verified the implementation and ensured that the correct scopes are being passed in the request.
Could you please help clarify the following? 1. Are there specific conditions under which Apple may not return the user’s fullName despite the scope being requested? 2. Is there a recommended approach or fallback mechanism to handle this scenario? 3. Could this behavior be related to a limitation or change in the API, or might it be an issue on my end?
I also came to know that for initial sign in the user details will be displayed in the signin-apple payload as Form data but how do I fetch those form-data from the signin-apple request, please suggest
I would greatly appreciate any guidance or solutions to resolve this issue.
Thank you for your support!
In these threads, it was clarified that Credential Provider Extensions must set both Backup Eligible (BE) and Backup State (BS) flags to 1 in authenticator data:
https://developer.apple.com/forums/thread/745605
https://developer.apple.com/forums/thread/787629
However, I'm developing a passkey manager that intentionally stores credentials only on the local device. My implementation uses:
kSecAttrAccessibleWhenUnlockedThisDeviceOnly for keychain items
kSecAttrTokenIDSecureEnclave for private keys
No iCloud sync or backup
These credentials are, by definition, single-device credentials. According to the WebAuthn specification, they should be represented with BE=0, BS=0.
Currently, I'm forced to set BE=1, BS=1 to make the extension work, which misrepresents the actual backup status to relying parties. This is problematic because:
Servers using BE/BS flags for security policies will incorrectly classify these as synced passkeys
Users who specifically want device-bound credentials for higher security cannot get accurate flag representation
Request: Please allow Credential Provider Extensions to return credentials with BE=0, BS=0 for legitimate device-bound passkey implementations.
Environment: macOS 26.2 (25C56), Xcode 26.2 (17C52)
Topic:
Privacy & Security
SubTopic:
General
Tags:
Extensions
macOS
Authentication Services
Passkeys in iCloud Keychain
Hello,
I am working on a script to update an application which bundle ID changed. Only the bundle ID was modified; all other aspects remain unchanged.
This application requires access to "Screen & System Audio Recording" permissions, which are currently granted to the old bundle ID.
The script performs the following steps:
launchctl bootout gui/$(id -u) /Library/LaunchAgents/com.my_agent_1.plist
pkgutil --forget com.my_agent_1
tccutil reset All com.my_agent_1
rm /Library/LaunchAgents/com.my_agent_1.plist
rm -rf </path/to/com_my_agent_1>
installer -dumplog -allowUntrusted -pkg </path/to/com_my_agent_2.pkg> -target /
...
When running steps #1-6 without a restart between steps #5 and #6, the old bundle ID (com.my_agent_1) remains visible in TCC.db (verified via SQL queries).
Looks like this is the reason why "com.my_agent_2" is not automatically added to the permission list (requiring manual add).
Moreover, "tccutil reset All com.my_agent_1" does not work anymore, the error:
tccutil: No such bundle identifier "com.my_agent_1": The operation couldn’t be completed. (OSStatus error -10814.)
Is there any way to completely clear the "Privacy & Security" permissions without requiring a system restart?
Thank you a lot for your help in advance!
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?
Topic:
Privacy & Security
SubTopic:
General
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
Topic:
Privacy & Security
SubTopic:
General
Tags:
Passkeys in iCloud Keychain
Authentication Services