iPhone --- 3DES Encryption returns "wrong" results?
- by Jan Gressmann
Hello fellow developers,
I have some serious trouble with a CommonCrypto function. There are two existing applications for BlackBerry and Windows Mobile, both use Triple-DES encryption with ECB mode for data exchange. On either the encrypted results are the same.
Now I want to implent the 3DES encryption into our iPhone application, so I went straight for CommonCrypto:
http://www.opensource.apple.com/source/CommonCrypto/CommonCrypto-32207/CommonCrypto/CommonCryptor.h
I get some results if I use CBC mode, but they do not correspond with the results of Java or C#. Anyway, I want to use ECB mode, but I don't get this working at all - there is a parameter error showing up...
This is my call for the ECB mode... I stripped it a little bit:
const void *vplainText;
plainTextBufferSize = [@"Hello World!" length];
bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
plainText = (const void *) [@"Hello World!" UTF8String];
NSString *key = @"abcdeabcdeabcdeabcdeabcd";
ccStatus = CCCrypt(kCCEncrypt,
kCCAlgorithm3DES,
kCCOptionECBMode,
key,
kCCKeySize3DES,
nil, // iv, not used with ECB
plainText,
plainTextBufferSize,
(void *)bufferPtr, // output
bufferPtrSize,
&movedBytes);
t is more or less the code from here: http://discussions.apple.com/thread.jspa?messageID=9017515
But as already mentioned, I get a parameter error each time...
When I use kCCOptionPKCS7Padding instead of kCCOptionECBMode and set the same initialization vector in C# and my iPhone code, the iPhone gives me different results. Is there a mistake by getting my output from the bufferPtr? Currently I get the encrypted stuff this way:
NSData *myData = [NSData dataWithBytes:(const void *)bufferPtr length:(NSUInteger)movedBytes];
result = [[NSString alloc] initWithData:myData encoding:NSISOLatin1StringEncoding];
It seems I almost tried every setting twice, different encodings and so on... where is my error?
