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我目前在 iOS 中加密并在 PHP 中解密。如果我正在加密/解密的字符串长度小于 16 个字符,它工作正常。

要加密的 iOS 代码:

    - (NSData *)AES128Encrypt:(NSData *)this
{
    // ‘key’ should be 16 bytes for AES128
    char keyPtr[kCCKeySizeAES128 + 1]; // room for terminator (unused)
    bzero( keyPtr, sizeof( keyPtr ) ); // fill with zeroes (for padding)
    NSString *key = @"1234567890123456";
    // fetch key data
    [key getCString:keyPtr maxLength:sizeof( keyPtr ) encoding:NSUTF8StringEncoding];

    NSUInteger dataLength = [this length];

    //See the doc: For block ciphers, the output size will always be less than or
    //equal to the input size plus the size of one block.
    //That’s why we need to add the size of one block here
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc( bufferSize );

    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt( kCCEncrypt, kCCAlgorithmAES128, kCCOptionECBMode | kCCOptionPKCS7Padding,
                                          keyPtr, kCCKeySizeAES128,
                                          NULL /* initialization vector (optional) */,
                                          [this bytes], dataLength, /* input */
                                          buffer, bufferSize, /* output */
                                          &numBytesEncrypted );
    if( cryptStatus == kCCSuccess )
    {
        //the returned NSData takes ownership of the buffer and will free it on deallocation
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }

    free( buffer ); //free the buffer
    return nil;
}

PHP代码解密:

function decryptThis($key, $pass)
{

    $base64encoded_ciphertext = $pass;

    $res_non = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $base64encoded_ciphertext, MCRYPT_MODE_CBC);

    $decrypted = $res_non;
    $dec_s2 = strlen($decrypted);

    $padding = ord($decrypted[$dec_s2-1]);
    $decrypted = substr($decrypted, 0, -$padding);

    return  $decrypted;
}

如果解密的字符串超过 16 个字符,PHP 只返回@"\n\n"但是,像 ' what '这样的短字符串会被正确解密,并且 PHP 返回@"what\n\n"。这里发生了什么?我希望能够解密 500 多个字符长的字符串。

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1 回答 1

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您在 iOS 中使用 ECB 模式,在 PHP 中使用 CBC。此外,PHP 不会检测到不正确的填充,因此如果(不正确的)填充纯文本的最后一个字节具有很高的值,它可能会生成一个空字符串。

于 2013-03-19T17:32:22.463 回答