【发布时间】：2023-03-23 18:33:01
【问题描述】：
在将请求发送到后端服务器之前，我需要对其进行签名。但是私钥给了我。所以我需要导入它，然后用它来签名。我能够导入和登录，但该数据与我使用 openssl 签名获得的数据不同。我知道它做错了，因为当我导入公钥时，我也无法验证它。如果有一种方法可以避免导入钥匙串，那也很棒。 这几天一直在努力工作，这对我们来说是一项高优先级的工作。有人可以帮忙吗？
- (SecKeyRef) getPrivateKey {
//RSA KEY BELOW IS DUMMY.
key = @"-----BEGIN RSA PRIVATE KEY-----\nORtMei3ImKI2ZKI636I4+uNCwFfZv9pyJzXyfr1ZNo7iaiW7A0NjLxikNxrWpr/M\n6HD8B2j/CSjRPW3bhsgDXAx/AI1aSfJFxazjiTxx2Lk2Ke3jbhE=\n-----END RSA PRIVATE KEY-----\n";
NSString * tag = @"adpPrivateKey";
NSString *s_key = [NSString string];
NSArray *a_key = [key componentsSeparatedByString:@"\n"];
BOOL f_key = FALSE;
for (NSString *a_line in a_key) {
if ([a_line isEqualToString:@"-----BEGIN RSA PRIVATE KEY-----"]) {
f_key = TRUE;
}
else if ([a_line isEqualToString:@"-----END RSA PRIVATE KEY-----"]) {
f_key = FALSE;
}
else if (f_key) {
s_key = [s_key stringByAppendingString:a_line];
}
}
if (s_key.length == 0) return(nil);
// This will be base64 encoded, decode it.
NSData *d_key = [NSData dataFromBase64String:s_key];
if(d_key == nil) return nil;
NSData *d_tag = [NSData dataWithBytes:[tag UTF8String] length:[tag length]];
// Delete any old lingering key with the same tag
NSMutableDictionary *privateKey = [[NSMutableDictionary alloc] init];
[privateKey setObject:(id) kSecClassKey forKey:(id)kSecClass];
[privateKey setObject:(id) kSecAttrKeyTypeRSA forKey:(id)kSecAttrKeyType];
[privateKey setObject:d_tag forKey:(id)kSecAttrApplicationTag];
SecItemDelete((CFDictionaryRef)privateKey);
CFTypeRef persistKey = nil;
// Add persistent version of the key to system keychain
[privateKey setObject:d_key forKey:(id)kSecValueData];
[privateKey setObject:(id) kSecAttrKeyClassPrivate forKey:(id)
kSecAttrKeyClass];
[privateKey setObject:[NSNumber numberWithBool:YES] forKey:(id)
kSecReturnPersistentRef];
OSStatus secStatus = SecItemAdd((CFDictionaryRef)privateKey, &persistKey);
if (persistKey != nil) CFRelease(persistKey);
if ((secStatus != noErr) && (secStatus != errSecDuplicateItem)) {
[privateKey release];
return(nil);
}
// Now fetch the SecKeyRef version of the key
SecKeyRef keyRef = nil;
[privateKey removeObjectForKey:(id)kSecValueData];
[privateKey removeObjectForKey:(id)kSecReturnPersistentRef];
[privateKey setObject:[NSNumber numberWithBool:YES] forKey:(id)kSecReturnRef
];
[privateKey setObject:(id) kSecAttrKeyTypeRSA forKey:(id)kSecAttrKeyType];
secStatus = SecItemCopyMatching((CFDictionaryRef)privateKey,
(CFTypeRef *)&keyRef);
if(secStatus != noErr)
return nil;
[privateKey release];
return keyRef;
}
以下代码用于签名。部分代码来自 Apple 示例 (http://developer.apple.com/library/ios/#samplecode/CryptoExercise/Listings/Classes_SecKeyWrapper_m.html#//apple_ref/doc/uid/DTS40008019-Classes_SecKeyWrapper_m-DontLinkElementID_17)
- (NSData *)getSignatureBytes:(NSString *)plainText {
OSStatus sanityCheck = noErr;
NSData * signedHash = nil;
uint8_t * signedHashBytes = NULL;
size_t signedHashBytesSize = 0;
SecKeyRef privateKey = NULL;
privateKey = [self getPrivateKey];
signedHashBytesSize = SecKeyGetBlockSize(privateKey);
//Create a SHA Encoded
NSString * shaEncoded = [self sha256:plainText];
NSLog(@"%@", shaEncoded);
// Malloc a buffer to hold signature.
signedHashBytes = malloc( signedHashBytesSize * sizeof(uint8_t) );
memset((void *)signedHashBytes, 0x0, signedHashBytesSize);
NSData *inputData = [self getHashBytes:[plainText dataUsingEncoding:NSUTF8StringEncoding]];
int bytesLengthUINT8 = [inputData length];
sanityCheck = SecKeyRawSign ( privateKey, kSecPaddingPKCS1, (const uint8_t *)inputData, CC_SHA256_DIGEST_LENGTH,(uint8_t *)signedHashBytes, &signedHashBytesSize);
if(sanityCheck != noErr)
return nil;
signedHash = [NSData dataWithBytes:(const void *)signedHashBytes length:(NSUInteger)signedHashBytesSize];
NSString *string = [signedHash base64EncodedString];
NSLog(@"%@", string);
if (signedHashBytes) free(signedHashBytes);
return signedHash;
}
我使用http://blog.flirble.org/2011/01/05/rsa-public-key-openssl-ios/中的代码示例导入公钥并验证失败。
【问题讨论】：
-
kSecPaddingPKCS1的值是多少？你能尝试比较一下公钥和私钥的模数吗？ -
嗨@owlstead，你能详细说明该怎么做吗？您还看到我保存和检索私钥的方式有任何问题吗？如果有其他可用的库可供我使用，请告诉我。
-
对不起，我不是ios专家。不过，我现在对加密做了很多，所以我想我给你一些一般性的建议。例如。
kSecPaddingPKCS1没有指定哈希值，SHA-1 很可能是默认值。如果私钥和公钥的模数不匹配，则它们不属于同一密钥对。在这两种情况下，签名验证都会失败。 -
嗨@owlstead，iOS 不支持我想要的 SHA256 填充。所以我实际上使用 SHA256 输入，然后使用 kSecPaddingPKCS1 假设它不会再做任何散列。
-
还有，你有什么进展吗，或者你还在努力吗？
标签： iphone ios cryptography rsa keychain