how to use aes mode to encrypt string in swift?

Question

I've searched for a lot of articles online and only find [iOS 3DES with ECB return half correct data ] on Stackoverflow, however when I copy the code in this article, the complier returns a different encrypted result with that I got from the online encrypt tools.

Can anyone help me here?
Thanks

plus, I can't really read obj-c. Just turned to swift from javascript and PHP.

===========Edit===========

Now, I changed my method to AES using swift 1.2. Code is listed as follows(iv and key are kept static for test):

    let key:String = "12345678901234567890123456789012"
    let iv:String =  "12345678901234567890123456789012"

    let keyData: NSData! = (key as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
    let keyBytes         = UnsafePointer<UInt8>(keyData.bytes)
    let keyLength        = size_t(kCCKeySizeAES256)

    let plainData: NSData! = (plainText as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
    let dataLength    = size_t(plainData.length)
    let dataBytes     = UnsafePointer<UInt8>(plainData.bytes)

    var bufferData    = NSMutableData(length: Int(dataLength) + kCCBlockSizeAES128)!
    var bufferPointer = UnsafeMutablePointer<UInt8>(bufferData.mutableBytes)
    let bufferLength  = size_t(bufferData.length)

    let operation: CCOperation = UInt32(kCCEncrypt)
    let algoritm:  CCAlgorithm = UInt32(kCCAlgorithmAES128)
    let options:   CCOptions = UInt32(kCCOptionPKCS7Padding)

    let ivData: NSData! = (iv as NSString).dataUsingEncoding(NSUTF8StringEncoding) as NSData!
    let ivPointer = UnsafePointer<UInt8>(ivData.bytes)

    var numBytesEncrypted: size_t = 0

    var cryptStatus = CCCrypt(operation, algoritm, options, keyBytes, keyLength, ivPointer, dataBytes, dataLength, bufferPointer, bufferLength, &numBytesEncrypted)

And here's my PHP code:

    function addPkcs7Padding($string) {
        $cipher = MCRYPT_RIJNDAEL_256;
        $mode = MCRYPT_MODE_CBC;
        $blocksize = mcrypt_get_iv_size($cipher, $mode);
        $len = strlen($string);
        $pad = $blocksize - ($len % $blocksize);
        $string .= str_repeat(chr($pad), $pad);
        return $string;
    }

    function aes256cbcEncrypt($str, $iv, $key ) {
        return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, addPkcs7Padding($str) , MCRYPT_MODE_CBC, $iv));
    }

Note that DES and 3DES should not be used for new work, only for compatibility with existing legacy implementations. The current standard is AES. Additionally ECB mode is a very poor choice, it lacks the security of CBC mode. — zaph, Apr 07 '15 at 11:32
Thanks Zaph, but now when I changed my encryption method to AES256 with PKCS7 padding, the result is different from what I get from a PHP server. I pasted my code above, how should I solve this problem? — Fantasy Tu, Apr 11 '15 at 17:32

score 0 · Accepted Answer · edited May 23 '17 at 11:58

0

You are not setting the length of the encrypted data to the value returned by reference: numBytesEncrypted. In this case: bufferData.length = numBytesEncrypted.
MCRYPT_RIJNDAEL_256 specifies a block size of 256 bits, AES only uses a block size of 128, change that in mcrypt to MCRYPT_RIJNDAEL_128. Note: the block size is not the same thing as the key size.
The iv size is the block size (128-bits/16-bytes).
Show example input and output data for more help.

For a Swift example this SO answer:

edited May 23 '17 at 11:58

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answered Apr 11 '15 at 22:41

zaph

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Thanks again for the quick reply. How should I set numBytesEncrypted anyway? Lots of docs online said that before the encryption, numBytesEncrypted should be set to zero in the type of size_t. – Fantasy Tu Apr 12 '15 at 01:34

how to use aes mode to encrypt string in swift?

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