在IOS中实施AES256加密

Question

这是我的java代码.现在我想在Objective-C中实现相同的功能.

Cipher encryptCipher;
IvParameterSpec iv = new IvParameterSpec(key);
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
encryptCipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
encryptCipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
byte[] encrypted = encryptCipher.doFinal(dataToEncrypt.getBytes());
Log.d("TAG", "encrypted string:"
        + Base64.encodeToString(encrypted, Base64.DEFAULT));
return Base64.encodeToString(encrypted, Base64.DEFAULT).trim();

这是我的iOS实现

- (NSData *)AES256EncryptWithKey:(NSString*)key
{
    char keyPtr[kCCKeySizeAES256 + 1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    NSUInteger dataLength = [self length];

    size_t bufferSize           = dataLength + kCCBlockSizeAES128;
    void* buffer                = malloc(bufferSize);

    size_t numBytesEncrypted    = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
                                  kCCAlgorithmAES128,
                                  kCCOptionPKCS7Padding,
                                  keyPtr,
                                  kCCKeySizeAES256,
                                  NULL,
                                  [self bytes],
                                  dataLength,
                                  buffer,
                                  bufferSize, 
                                  &numBytesEncrypted);

    if (cryptStatus == kCCSuccess)
    {

        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }

    free(buffer);
    return nil;
}

这是我的哈希密钥生成函数.这个函数在android和ios中返回相同的键

int dkLen = 16;
    NSData *keyData = [hash_key dataUsingEncoding:NSUTF8StringEncoding];
    NSData *salt    = [saltKey dataUsingEncoding:NSUTF8StringEncoding];
    uint    rounds  = 1000;
    uint    keySize = kCCKeySizeAES128;

    NSMutableData *derivedKey = [NSMutableData dataWithLength:keySize];





    CCKeyDerivationPBKDF(kCCPBKDF2,               // algorithm
                         keyData.bytes,           // password
                         keyData.length,          // passwordLength
                         salt.bytes,              // salt
                         salt.length,             // saltLen
                         kCCPRFHmacAlgSHA1,       // PRF
                         rounds,                  // rounds
                         derivedKey.mutableBytes, // derivedKey
                         dkLen*8);
 return derivedKey;

我得到了不同的输出.我做错了什么？.请帮助我找出答案.

Answer 1

一个问题是Java代码使用CBC模式,iOS代码使用ECB模式.

接下来,从引用的项目:
//result= yHbhApwTpQ2ZhE97AKF/g==
无效的Base64,它不包含4个字节的倍数.

有了这些选项:CBC,PKCS#7填充

inputs:  
   data in: "hello" which will be null padded to the block length of 16-bytes  
   key:  
      base64: VQQhu+dUdqXGoE7RZL2JWg==  
      hex: 550421bbe75476a5c6a04ed164bd895a  
   iv:   
      base64: VQQhu+dUdqXGoE7RZL2JWg==  
      hex: 550421bbe75476a5c6a04ed164bd895a  
encrypted output:  
   hex: ff21db840a704e943666113dec0285fe  
   base64: /yHbhApwTpQ2ZhE97AKF/g==  

这是测试代码:

NSString *base64Key  = @"VQQhu+dUdqXGoE7RZL2JWg==";
NSString *dataString = @"hello";

NSData *key  = [[NSData alloc] initWithBase64EncodedString:base64Key  options:0];
NSData *data = [dataString dataUsingEncoding:NSUTF8StringEncoding];

NSLog(@"key:  %@", key);
NSLog(@"data: %@", data);

NSData *encryptedData = [TestClass crypt:data
                                 iv:key
                                key:key
                            context:kCCEncrypt];

NSLog(@"encryptedData: %@", encryptedData);
NSString *encryptedBase64Data = [encryptedData base64EncodedStringWithOptions:0];
NSLog(@"encryptedBase64Data: %@", encryptedBase64Data);

这是加密方法(在课堂上TestClass):

+ (NSData *)crypt:(NSData *)dataIn
                  iv:(NSData *)iv
                 key:(NSData *)symmetricKey
             context:(CCOperation)encryptOrDecrypt
{
    CCCryptorStatus ccStatus   = kCCSuccess;
    size_t          cryptBytes = 0;    // Number of bytes moved to buffer.
    NSMutableData  *dataOut    = [NSMutableData dataWithLength:dataIn.length + kCCBlockSizeAES128];

    ccStatus = CCCrypt( encryptOrDecrypt,
                       kCCAlgorithmAES128,
                       kCCOptionPKCS7Padding,
                       symmetricKey.bytes,
                       kCCKeySizeAES128,
                       iv.bytes,
                       dataIn.bytes,
                       dataIn.length,
                       dataOut.mutableBytes,
                       dataOut.length,
                       &cryptBytes);

    if (ccStatus != kCCSuccess) {
        NSLog(@"CCCrypt status: %d", ccStatus);
    }

    dataOut.length = cryptBytes;

    return dataOut;
}

注意:我将加密和数据转换分开.将它们混淆只会使测试变得更加复杂.

如果使用在线加密实现,则填充可能不是PKCS#7,因为mcrypt不支持它,而是执行非标准空填充.由于填充字节只是填充字节的计数,因此可以在输入中模拟填充.以下是使用AES - Symmetric Ciphers Online的示例

请注意,"你好" PKCS#7填充到16个字节的块大小增加了11个字节的值UINT8 11或的0x0B:68656c6c6f0B0B0B0B0B0B0B0B0B0B0B.

最后问题仍然是为什么Java代码不会产生这个结果？