Question

我正在尝试使用CryptoExercise的SecKeyWrapper addPeerPublicKey:keyBits:方法将RSA公钥添加到我的iPhone的钥匙串中。这种方法的逻辑是它首先尝试将密钥添加到密钥链中，如果它已经存在(sanityCheck==errSecDuplicateItem)，它会尝试通过调用SecKeyItemCopyMatching()从密钥链中检索此密钥。

这正是我的情况：密钥已经存在于钥匙串中，因此呼叫SecKeyItemAdd() returns errSecDuplicateItem。

然后它尝试检索现有密钥但SecKeyItemCopyMatching() returns 0（表示没有错误），但第二个参数（peerKeyRef）仍然是零。

这怎么可能？这有什么问题？

以下是来自CryptoExercise示例的[SecKeyWrapper addPeerPublicKey:keyBits:]代码供参考：

- (SecKeyRef)addPeerPublicKey:(NSString *)peerName keyBits:(NSData *)publicKey {
    OSStatus sanityCheck = noErr;
    SecKeyRef peerKeyRef = NULL;
    CFTypeRef persistPeer = NULL;

    LOGGING_FACILITY( peerName != nil, @"Peer name parameter is nil." );
    LOGGING_FACILITY( publicKey != nil, @"Public key parameter is nil." );

    NSData *peerTag = [[NSData alloc] initWithBytes:(const void *) [peerName UTF8String] length:[peerName length]];
    NSMutableDictionary *peerPublicKeyAttr = [[NSMutableDictionary alloc] init];

    [peerPublicKeyAttr setObject:(__bridge id) kSecClassKey forKey:(__bridge id) kSecClass];
    [peerPublicKeyAttr setObject:(__bridge id) kSecAttrKeyTypeRSA forKey:(__bridge id) kSecAttrKeyType];
    [peerPublicKeyAttr setObject:peerTag forKey:(__bridge id) kSecAttrApplicationTag];
    [peerPublicKeyAttr setObject:publicKey forKey:(__bridge id) kSecValueData];
    [peerPublicKeyAttr setObject:[NSNumber numberWithBool:YES] forKey:(__bridge id) kSecReturnPersistentRef];

    sanityCheck = SecItemAdd((__bridge CFDictionaryRef) peerPublicKeyAttr, (CFTypeRef *) &persistPeer);

    // The nice thing about persistent references is that you can write their value out to disk and
    // then use them later. I don't do that here but it certainly can make sense for other situations
    // where you don't want to have to keep building up dictionaries of attributes to get a reference.
    //
    // Also take a look at SecKeyWrapper's methods (CFTypeRef)getPersistentKeyRefWithKeyRef:(SecKeyRef)key
    // & (SecKeyRef)getKeyRefWithPersistentKeyRef:(CFTypeRef)persistentRef.

    LOGGING_FACILITY1( sanityCheck == noErr || sanityCheck == errSecDuplicateItem, @"Problem adding the peer public key to the keychain, OSStatus == %ld.", sanityCheck );

    if (persistPeer) {
        peerKeyRef = [self getKeyRefWithPersistentKeyRef:persistPeer];
    } else {
        [peerPublicKeyAttr removeObjectForKey:(__bridge id) kSecValueData];
        [peerPublicKeyAttr setObject:[NSNumber numberWithBool:YES] forKey:(__bridge id) kSecReturnRef];
        // Let's retry a different way.
        sanityCheck = SecItemCopyMatching((__bridge CFDictionaryRef) peerPublicKeyAttr, (CFTypeRef *) &peerKeyRef);
    }

    LOGGING_FACILITY1( sanityCheck == noErr && peerKeyRef != NULL, @"Problem acquiring reference to the public key, OSStatus == %ld.", sanityCheck );

    if (persistPeer) CFRelease(persistPeer);
    return peerKeyRef;
}

Answer 1

我遇到了同样的问题，我假设您尝试导入未从其他iOS设备导出的RSA密钥。

原因似乎是一种不兼容的密钥格式 - 详细地说，iOS期望不要设置一些ASN1标头。为什么函数返回OK对我来说只能解释一个bug ...

查看http://blog.flirble.org/2011/01/05/rsa-public-key-openssl-ios/处的代码这是正确的解决方案，对我有用 - 感谢Chris Luke

SecItemCopyMatching返回nil值而没有任何错误

1 个答案: