IOS DES加密和PHP解密无法可靠地工作

Question

I'm encrypting a string in iOS using the method below

-(NSString *) encrypt:(NSString *) data 
{

    const void *vplainText;
    size_t plainTextBufferSize = [data length];
    vplainText = (const void *) [data UTF8String];
    CCCryptorStatus ccStatus;
    uint8_t *bufferPtr = NULL;
    size_t bufferPtrSize = 0;
    size_t movedBytes = 0;

    bufferPtrSize = (plainTextBufferSize + kCCBlockSizeDES) & ~(kCCBlockSizeDES - 1);
    bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));
    memset((void *)bufferPtr, 0x0, bufferPtrSize);

    Byte iv [] = {0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef};

    NSString *key = @"complexkey";
    const void *vkey = (const void *) [key UTF8String];

    ccStatus = CCCrypt(kCCEncrypt,
                       kCCAlgorithmDES,
                       kCCOptionPKCS7Padding | kCCOptionECBMode,
                       vkey,
                       kCCKeySizeDES,
                       iv,
                       vplainText,
                       plainTextBufferSize,
                       (void *)bufferPtr,
                       bufferPtrSize,
                       &movedBytes);

    NSData *myData = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes];
    NSString *result = [myData base64Encoding];

    // url encode the result
    return (__bridge NSString *) CFURLCreateStringByAddingPercentEscapes(NULL,
                                        (__bridge CFStringRef) result,
                                        NULL,
                                        (__bridge CFStringRef) @"!*'();:@&=+$,/?%#[]",
                                        kCFStringEncodingUTF8);
}

And on php, I'm decrypting the string as follows -

$decrypted = mcrypt_decrypt(MCRYPT_DES, 'complexkey', base64_decode(urldecode($encrypted)), MCRYPT_MODE_ECB);

This seems to work correctly 75% of the time and I'm not sure why it fails at other times. Any clues? Thanks for the help!

Answer 1

It turns out that there was nothing wrong in the encryption/decryption I was doing. Rather the issue was that urldecode() in PHP wasn't decoding '%2B' to '+' (but instead to ' '). I switched from urldecode() to rawurldecode() in PHP and everything is working fine now!