ios - 使用 kSecAttrAccessible 将 RSA 公钥存储到 iOS 钥匙串(keychain)中

Question

所以我知道我可以使用以下代码将 RSA key 存储到钥匙串(keychain)中:

+ (void)savePublicKeyToKeychain:(NSData *)key tag:(NSString *)tagString deleteExisting:(BOOL)deleteExisting {
    NSData *tag = [SecKeyWrapper getKeyTag:tagString];

    NSDictionary *saveDict = @{
            (__bridge id) kSecClass : (__bridge id) kSecClassKey,
            (__bridge id) kSecAttrKeyType : (__bridge id) kSecAttrKeyTypeRSA,
            (__bridge id) kSecAttrApplicationTag : tag,
            (__bridge id) kSecAttrKeyClass : (__bridge id) kSecAttrKeyClassPublic,
            (__bridge id) kSecValueData : key
    };
    [self saveKeyToKeychain:saveDict tag:tagString deleteExisting:deleteExisting];
}

+ (void)saveKeyToKeychain:(NSDictionary *)saveDict tag:(NSString *)tagString deleteExisting:(BOOL)deleteExisting {
    OSStatus sanityCheck = SecItemAdd((__bridge CFDictionaryRef) saveDict, NULL);
    if (sanityCheck != errSecSuccess) {
        if (sanityCheck == errSecDuplicateItem && deleteExisting) {
            // delete the duplicate and save again
            SecItemDelete((__bridge CFDictionaryRef) saveDict);
            sanityCheck = SecItemAdd((__bridge CFDictionaryRef) saveDict, NULL);
        }
        if (sanityCheck != errSecSuccess) {
            NSLog(@"Problem saving the key to keychain, OSStatus == %d.", (int) sanityCheck);
        }
    }
    // remove from cache
    [keyCache removeObjectForKey:tagString];
}

这个我可以正确保存和检索。如果我尝试在保存时设置 kSecAttrAccessible 值:

+ (void)savePublicKeyToKeychain:(NSData *)key tag:(NSString *)tagString deleteExisting:(BOOL)deleteExisting {
    NSData *tag = [SecKeyWrapper getKeyTag:tagString];

    NSDictionary *saveDict = @{
            (__bridge id) kSecClass : (__bridge id) kSecClassKey,
            (__bridge id) kSecAttrKeyType : (__bridge id) kSecAttrKeyTypeRSA,
            (__bridge id) kSecAttrApplicationTag : tag,
            (__bridge id) kSecAttrKeyClass : (__bridge id) kSecAttrKeyClassPublic,
            (__bridge id) kSecAttrAccessible: (__bridge id) kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly,
            (__bridge id) kSecValueData : key
    };
    [self saveKeyToKeychain:saveDict tag:tagString deleteExisting:deleteExisting];
}

然后尝试检索，我得到了垃圾。它是垃圾，因为当我保存后立即检索它时，插入的值和检索到的值是不同的。

有人有代码示例或知道如何设置钥匙串(keychain)项目的可访问性，尤其是 RSA key 吗？

Answer 1

众所周知，用于将数据存储到钥匙串(keychain)的属性需要完全用于从钥匙串(keychain)检索数据的属性。如果您缺少其中一个属性，即使它看起来像是仅用于存储的属性(如 kSecAttrAccessible)，您也会得到错误的数据。您甚至不会得到 errSecItemNotFound。它返回垃圾。