Question

3DES加密工作正常，并且使用相同的逻辑获得了错误的解密值。

请找到以下逻辑来调用加密/解密方法

NSString *cipherEnString = [self doCipher:@"Test" enc:kCCEncrypt];
NSString *cipherDecString = [self doCipher:cipherEnString enc:kCCDecrypt];

下面添加了加密/解密的代码。

- (NSString*) doCipher:(NSString*)plainText enc:(CCOperation)encryptOrDecrypt{
    const void *vplainText;
    size_t plainTextBufferSize;
    if (encryptOrDecrypt == kCCDecrypt)
    {
        NSString *encStr = [self encodeStringTo64:plainText];
        NSData *EncryptData = [encStr dataUsingEncoding:NSUTF8StringEncoding];        
        plainTextBufferSize = [EncryptData length];
        vplainText = [EncryptData bytes];
    }
    else
    {
        plainTextBufferSize = [plainText length];
        vplainText = (const void *) [plainText UTF8String];
    }

    CCCryptorStatus ccStatus;
    uint8_t *bufferPtr = NULL;
    size_t bufferPtrSize = 0;
    size_t movedBytes = 0;
    //  uint8_t ivkCCBlockSize3DES;

    bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);

    bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));
    memset((void *)bufferPtr, 0x0, bufferPtrSize);

    unsigned char secretKey[24]=  {0x01, 0x02, 0x03, 0x05, 0x07, 0x0B, 0x0D, 0x11,0x12, 0x11, 0x0D, 0x0B, 0x07, 0x02, 0x04,0x08,0x01, 0x02, 0x03, 0x05, 0x07, 0x0B, 0x0D, 0x11};
    unsigned char IV3[8]={0x01, 0x02, 0x03, 0x05, 0x07, 0x0B, 0x0D, 0x11};

    uint8_t iv[kCCBlockSize3DES];
    memset((void *) iv, 0x0, (size_t) sizeof(iv));

    ccStatus = CCCrypt(encryptOrDecrypt,
                       kCCAlgorithm3DES,
                       kCCOptionPKCS7Padding ,
                       secretKey, //"123456789012345678901234", //key
                       kCCKeySize3DES,
                       IV3 ,  //iv,
                       vplainText,  //plainText,
                       plainTextBufferSize,
                       (void *)bufferPtr,
                       bufferPtrSize,
                       &movedBytes);

    /*else*/ if (ccStatus == kCCParamError) return @"PARAM ERROR";
    else if (ccStatus == kCCBufferTooSmall) return @"BUFFER TOO SMALL";
    else if (ccStatus == kCCMemoryFailure) return @"MEMORY FAILURE";
    else if (ccStatus == kCCAlignmentError) return @"ALIGNMENT";
    else if (ccStatus == kCCDecodeError) return @"DECODE ERROR";
    else if (ccStatus == kCCUnimplemented) return @"UNIMPLEMENTED";

    NSString *result;
    if (encryptOrDecrypt == kCCDecrypt)
    {
        result = [ [NSString alloc] initWithData: [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes] encoding:NSASCIIStringEncoding];
        NSString *s = [[NSString alloc] initWithBytes:bufferPtr
                                               length:movedBytes
                                             encoding:NSUTF8StringEncoding];
        NSLog(@"%@",s);
    }
    else
    {
        NSData *myData = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes];
        NSString *base64String = [myData base64EncodedStringWithOptions:0];
        return base64String;
    }
    return result;
}

- (NSString*)encodeStringTo64:(NSString*)fromString
{
    NSData *plainData = [fromString dataUsingEncoding:NSUTF8StringEncoding];
    NSString *base64String;
    if ([plainData respondsToSelector:@selector(base64EncodedStringWithOptions:)]) {
        base64String = [plainData base64EncodedStringWithOptions:kNilOptions];  // iOS 7+
    } 
    else {
        NSString *base64String = [plainData base64EncodedStringWithOptions:0];
        NSLog(@"%@", base64String);// pre iOS7
    }
    return base64String;
}

Answer 1

您正在努力将base64加密字符串转换为加密数据：

电流：

NSString *encStr = [self encodeStringTo64:plainText];
NSData *encryptData = [encStr dataUsingEncoding:NSUTF8StringEncoding];

正确：

NSData *encryptData = [[NSData alloc] initWithBase64EncodedString:plainText options:0];

此外，您不需要以下方法：

- (NSString *)encodeStringTo64:(NSString*)fromString

添加几个要加密/解密的数据的十六进制转储会显示此问题。

最好创建一个基本加密方法，该方法接受并返回NSData并添加执行调用加密方法的任何编码/解码的方法。减少协作的混合使代码更简单，更容易理解和调试。

请参阅此SO answer，了解如何消除malloc，而只是使用NSMutableData。

在Objective-c中使用3DES解密String后出错

1 个答案: