如何将通用加密代码从 Objective-C 转换为 Swift？

Question

我正在致力于将 Objective-C 代码转换为 Swift。这里我们发现CommonCrypto在 Swift 中不可用。

因此，我们在我令人兴奋的 Swift 项目中使用映射来创建 module.map 文件并访问 Common Crypto 文件。我已经为 Objective-C 到 Swift 编写了以下代码。

但我在代码转换方面遇到了问题。下面我写了两种语言的代码。请注意此 SWIFT 代码包含错误。它并不完美。请帮我解决 Swift 语言代码。

Objective-C 代码：

- (NSData *) hashKey:(NSString *)hash{
    unsigned char result[1000];
    const char *cStr = [hash UTF8String];
    CC_MD5(cStr, (CC_LONG)strlen(cStr), result);

    for (int jval = 0, kval = 16; jval < 8;) {
        result[kval++] = result[jval++];
    }
    return [NSMutableData dataWithBytes:result length:24];;
}

- (NSData *) myEncrypt:(NSString *)encryptData{
    NSData *myKeyData = [self hashKey:MySecretKey];
    NSData *myRawData = [encryptData dataUsingEncoding:NSUTF8StringEncoding];

    size_t buffer_size           = [myRawData length] + kCCBlockSize3DES;
    void* buffer                 = malloc(buffer_size);
    size_t num_bytes_encrypted   = 0;

    uint8_t iv[8] = { 56, 101, 63, 23, 96, 182, 209, 205};

    CCCryptorStatus Crypto_status = CCCrypt(kCCEncrypt, kCCAlgorithm3DES, kCCOptionPKCS7Padding,
                                            [myKeyData bytes],
                                            kCCKeySize3DES,
                                            iv,
                                            [myRawData bytes],
                                            [myRawData length],
                                            buffer,
                                            buffer_size,
                                            &num_bytes_encrypted);

    if (Crypto_status == kCCSuccess){
        NSData *myResult = [NSData dataWithBytes:buffer length:num_bytes_encrypted];
        free(buffer);
        return myResult;
    }
    else {
        free(buffer);
        return nil;
    }
}


- (NSData *) myDecrypt:(NSData *)decryptData{

    NSUInteger mydata_len = [decryptData length];
    NSData *keyData = [self hashKey:MySecretKey];

    size_t buffer_size           = mydata_len + kCCBlockSizeAES128;
    void* buffer                 = malloc(buffer_size);
    size_t num_bytes_encrypted   = 0;

    uint8_t iv[8] = { 56, 101, 63, 23, 96, 182, 209, 205};

    CCCryptorStatus decrypt_status = CCCrypt(kCCDecrypt, kCCAlgorithm3DES, kCCOptionPKCS7Padding,
                                             [keyData bytes],
                                             kCCKeySize3DES,
                                             iv,
                                             [decryptData bytes],
                                             mydata_len,
                                             buffer,
                                             buffer_size,
                                             &num_bytes_encrypted);

    if (decrypt_status == kCCSuccess){
        NSData *myResult = [NSData dataWithBytes:buffer length:num_bytes_encrypted];
        free(buffer);
        return myResult;
    }
    else {
        free(buffer);
        return nil;
    }

}

SWIFT代码：

func hashKey(hash:String) -> NSData{

    let digestLength = Int(CC_MD5_DIGEST_LENGTH)
    let result = UnsafeMutablePointer<CUnsignedChar>.alloc(digestLength)
    var cStr = hash.cStringUsingEncoding(NSUTF8StringEncoding)
    var strLen = CC_LONG(strlen(cStr!))

    CC_MD5(cStr!, strLen, result)

    var kval = 16

    for (var jval=0; kval==16; jval<8){
    result [kval++] = result[jval++] ***//Here We Got An Error: Cannot assign a value of type 'CUnsignedChar' to a value of type '[Int]'***

    }

    return NSMutableData(bytes: result, length: 24)
}


func myEncrypt(encryptData:String) -> NSData?{

    var myKeyData : NSData = self.hashKey(MySecretKey)
    var myRawData : NSData = encryptData.dataUsingEncoding(NSUTF8StringEncoding)!

    var buffer_size : size_t = myRawData.length + kCCBlockSize3DES
    var buffer = UnsafeMutablePointer<NSData>.alloc(buffer_size)
    var num_bytes_encrypted : size_t = 0

    var iv : [UInt8] = [56, 101, 63, 23, 96, 182, 209, 205]

    let operation: CCOperation = UInt32(kCCEncrypt)
    let algoritm:  CCAlgorithm = UInt32(kCCAlgorithm3DES)
    let options:   CCOptions   = UInt32(kCCOptionPKCS7Padding)
    let keyLength        = size_t(kCCKeySize3DES)

    var Crypto_status: CCCryptorStatus = CCCrypt(operation, algoritm, options, myKeyData.bytes, keyLength, iv, myRawData.bytes, myRawData.length, buffer, buffer_size, &num_bytes_encrypted)

    if UInt32(Crypto_status) == UInt32(kCCSuccess){

    var myResult: NSData = NSData(bytes: buffer, length: num_bytes_encrypted)
    free(buffer)
    return myResult
}else{
    free(buffer)
    return nil
    }

}


func myDecrypt(decryptData : NSData) -> NSData?{

    var mydata_len : Int = decryptData.length
    var keyData : NSData = self.hashKey(MySecretKey)

    var buffer_size : size_t = mydata_len+kCCBlockSizeAES128
    var buffer = UnsafeMutablePointer<NSData>.alloc(buffer_size)
    var num_bytes_encrypted : size_t = 0

    var iv : [UInt8] = [56, 101, 63, 23, 96, 182, 209, 205]

    let operation: CCOperation = UInt32(kCCDecrypt)
    let algoritm:  CCAlgorithm = UInt32(kCCAlgorithm3DES)
    let options:   CCOptions   = UInt32(kCCOptionPKCS7Padding)
    let keyLength        = size_t(kCCKeySize3DES)

    var decrypt_status : CCCryptorStatus = CCCrypt(operation, algoritm, options, keyData.bytes, keyLength, iv, decryptData.bytes, mydata_len, buffer, buffer_size, &num_bytes_encrypted)

    if UInt32(decrypt_status) == UInt32(kCCSuccess){

    var myResult : NSData = NSData(bytes: buffer, length: num_bytes_encrypted)
    free(buffer)
    return myResult
}else{
    free(buffer)
    return nil

    }
}

Answer 1

for (var jval=0; kval==16; jval<8){
    return [kval++] = result[jval++] ***//Here We Got An Error: Cannot assign a value of type 'CUnsignedChar' to a value of type '[Int]'***
}

正如@Francisco 指出的，这是不正确的。您试图在循环中间返回。这是一个明显的错字。你的意思result[kval++]是不是return [kval++]。

但还有另一个问题。您修改了for循环。它是：

for (int jval = 0, kval = 16; jval < 8;) {

这在 Swift 中基本相同：

for var jval = 0, kval = 0; jval < 8; {