3des encryption in iphone - iphone

Question

i am fairly new to iOS development and objective c.
I am developing an application which will send encrypted data to a server.
The server uses 3des with cbc and no padding.
I have read most of the related questions in stackoverflow but still unable to get it work.
Been working on this for few days but still unable to get it to match with the server encryption.
Here is what i have work out:
NSString* plaintexthex = #"536176696E67204163636F756E747C313233343536000000";
NSData *dTextIn = [self dataFromHexString:plaintexthex]; //my own way of convert hex to data
NSString* keyhex = #"6E7B336FD2051BA165A9362BD9735531";
NSData *_keyData = [self dataFromHexString:keyhex]; //my own way of convert hex to data
CCCryptorStatus ccStatus;
uint8_t *bufferPtr = NULL;
size_t bufferPtrSize = 0;
size_t movedBytes = 0;
bufferPtrSize = ([dTextIn length] + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));
memset((void *)bufferPtr, 0x00, bufferPtrSize);
uint8_t iv[kCCBlockSize3DES];
memset((void *) iv, 0x00, (size_t) sizeof(iv));
unsigned char *bytePtr = (unsigned char *)[_keyData bytes];
ccStatus = CCCrypt(kCCEncrypt, // CCoperation op
kCCAlgorithm3DES, // CCAlgorithm alg
kCCModeCBC, // CCOptions
[_keyData bytes], // const void *key
kCCKeySize3DES, // 3DES key size length 24 bit
iv, // const void *iv,
[dTextIn bytes], // const void *dataIn
[dTextIn length], // size_t dataInLength
bufferPtr, // void *dataOut
bufferPtrSize, // size_t dataOutAvailable
&movedBytes); // size_t *dataOutMoved
NSString *result;
NSData *myData = [NSData dataWithBytes:(const void *)bufferPtr length: (NSUInteger)movedBytes];
result = [self hexStringFromData:myData];
NSLog(#"Data to encrypt %#",dTextIn);
NSLog(#"Encryption key %#",_keyData);
NSLog(#"Bytes of key are %s ", bytePtr);
NSLog(#"Key length %d ",[_keyData length]);
NSLog(#"Encrypted bytes %#", myData);
NSLog(#"Encrypted string %#", result);
NSLog(#"Encrypted string length %d", [result length]);
- (NSData *)dataFromHexString:(NSString *)string
{
NSMutableData *stringData = [[[NSMutableData alloc] init] autorelease];
unsigned char whole_byte;
char byte_chars[3] = {'\0','\0','\0'};
int i;
for (i=0; i < [string length] / 2; i++) {
byte_chars[0] = [string characterAtIndex:i*2];
byte_chars[1] = [string characterAtIndex:i*2+1];
whole_byte = strtol(byte_chars, NULL, 16);
[stringData appendBytes:&whole_byte length:1];
}
return stringData;
}
I have develop a similar application on the Android platform and it works well with the server.
Heres the encryption of the function i used on the Android platform.
public byte[] encrypt(byte[] key, byte[] message) throws Exception {
byte [] plainTextBytes = message;
byte[] encryptKey = key;
SecretKey theKey = new SecretKeySpec(encryptKey, "DESede");
Cipher cipher = Cipher.getInstance("DESede/CBC/NoPadding");
IvParameterSpec IvParameters = new IvParameterSpec(new byte[] {(byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00});
cipher.init(Cipher.ENCRYPT_MODE, theKey, IvParameters);
byte[] encrypted = cipher.doFinal(plainTextBytes);
return encrypted;
}
Basically i want to replicate this similar encryption to be used on the iOS platform.
Any help will be welcome and thank you in advance.

Answer 1

kCCModeCBC is a mode, not an option. The option you want is 0. CBC is the default mode for CCCrypt(). The default is also no padding.

Answer 2

I am an iOS user, not a developer, but as far as I know, iOS no longer supports 3DES. I use an iPad for VPN, and iOS 3 worked fine with 3DES encryption, but as of iOS 4, the minimum encryption level required is AES128.
Hope that helps.