3DES iOS encrypt different from .Net server - ios

Question

I'm trying to encrypt a request, I made this function but I'm getting a different encrypt value in the .NET server. This is the function I'm using in iOS:
- (NSData *)Encrypt3DESWithInput:(NSString *)input
key:(NSString *)key
{
NSData *inputData = [input dataUsingEncoding:NSUTF8StringEncoding];
NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
NSUInteger dataLength = [inputData length];
size_t bufferSize = dataLength + kCCBlockSize3DES;
void *buffer = malloc(bufferSize);
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
kCCAlgorithm3DES,
kCCOptionPKCS7Padding,
[keyData bytes],
kCCKeySize3DES,
initializationVector,
[inputData bytes],
dataLength,
buffer,
bufferSize,
&numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
NSLog(#"Success");
//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;
}
These are the values im using in the private key and the initialization vector:
static NSString *const privateKey = #"";
static const char initializationVector[8] = {31, 10, 35, 17, 0, 42, 151, 64};

Answer 1

Use a key that is the natural length of the encryption/decryption routine. Don't rely on key padding, that is undefined. If you have a password use PBKDF2 to create a full length secure key..
The key string is #"" yet the key data is created by [key dataUsingEncoding:NSUTF8StringEncoding]
NSString *keyString = #"";
NSData *keyData = [keyString dataUsingEncoding:NSUTF8StringEncoding];
NSLog output:
keyString: ''
keyData: <>
Note the key length is 0 so the DES method will access random data from memory.