Question

我在base64中有一个RSa publicKey值，如何在不添加Keychain的情况下转换为SecKeyRef对象我可以将RSA Raw值添加到不是X509格式的Keychain中吗？

提前致谢

Answer 1

以下代码来自Apple的CryptoExercise示例，位于SecKeyWrapper.m中。它假定“publicKey”NSData对象是二进制DER编码的ASN.1对象，而不是base-64编码。因此，您必须先获得base-64解码器并应用它。您可能还想阅读Apple Developer论坛中的this post。

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

    sanityCheck = SecItemAdd((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 == %d.", sanityCheck );

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

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

    [peerTag release];
    [peerPublicKeyAttr release];
    if (persistPeer) CFRelease(persistPeer);
    return peerKeyRef;
}

Answer 2

如果有人遇到这个问题并且正在寻找Cocoa答案：

NSData *privateKeyPEMData = [privateKeyPEM dataUsingEncoding:NSUTF8StringEncoding];
CFArrayRef imported = NULL;
SecKeychainRef importedKeychain = NULL;
OSStatus err = 0;
SecExternalFormat format = kSecFormatOpenSSL;
SecKeyRef privateKey = NULL;

[privateKeyString dataUsingEncoding:NSUTF8StringEncoding];
err = SecItemImport((__bridge CFDataRef)(privateKeyPEMData), (CFStringRef)@"pem", &format, NULL, kNilOptions, kNilOptions, importedKeychain, &imported);
NSLog(@"%@ ERROR: %@", self.class, [NSError errorWithDomain:NSOSStatusErrorDomain code:err userInfo:nil]);

assert(err == errSecSuccess);
assert(CFArrayGetCount(imported) == 1);
privateKey = (SecKeyRef)CFArrayGetValueAtIndex(imported, 0);

将原始RSA密钥值转换为SecKeyRef对象以进行加密

2 个答案: