Any cocoa source code for AES encryption decryption?

Question

I am searching for some cocoa code on AES encryption and I did some google search for it. I found this very useful link - http://iphonedevelopment.blogspot.com/2009/02/str

Answer 1

All examples I found didn't work for me, so I changed the solution above. This one works for me and uses the Google-Lib for Base64 stuff:

+ (NSData *)AES256DecryptWithKey:(NSString *)key data:(NSData*)data encryptOrDecrypt:(CCOperation)encryptOrDecrypt {

    // 'key' should be 32 bytes for AES256, will be null-padded otherwise
    char keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)
    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)

    // fetch key data
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    if (encryptOrDecrypt == kCCDecrypt)
    {
        data = [GTMBase64 decodeData:data];
    }

        NSUInteger dataLength = [data 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 numBytesDecrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(encryptOrDecrypt,
                                          kCCAlgorithmAES128,
                                          kCCOptionPKCS7Padding,
                                          keyPtr,
                                          kCCKeySizeAES256,
                                          NULL /* initialization vector (optional) */,
                                          [data bytes], dataLength, /* input */
                                          buffer,       bufferSize, /* output */
                                          &numBytesDecrypted);

    if (cryptStatus != kCCSuccess){ 
        NSLog(@"ERROR WITH FILE ENCRYPTION / DECRYPTION");
        return nil;
    }

    NSData *result;

    if (encryptOrDecrypt == kCCDecrypt)
    {
        result = [NSData dataWithBytes:(const void *)buffer length:(NSUInteger)numBytesDecrypted];
    }
    else
    {
        NSData *myData = [NSData dataWithBytes:(const void *)buffer length:(NSUInteger)numBytesDecrypted];
        result = [GTMBase64 encodeData:myData];
    }

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