3DES Encryption, ECB, CBC modes

3DES encryption. The Chilkat encryption component supports Triple-DES in both ECB (Electronic Cookbook) and CBC (Cipher-Block Chaining) cipher modes.

Download: Chilkat Cocoa Objective-C Libraries

NSMutableString *strOutput = [NSMutableString stringWithCapacity:1000];

CkoCrypt2 *crypt = [[[CkoCrypt2 alloc] init] autorelease];

BOOL success;
success = [crypt UnlockComponent: @"Anything for 30-day trial"];
if (success != YES) {
    [strOutput appendString: crypt.LastErrorText];
    [strOutput appendString: @"\n"];
    self.mainTextField.stringValue = strOutput;
    return;
}

//  Specify 3DES for the encryption algorithm:
crypt.CryptAlgorithm = @"3des";

//  CipherMode may be "ecb" or "cbc"
crypt.CipherMode = @"cbc";

//  KeyLength must be 192.  3DES is technically 168-bits;
//  the most-significant bit of each key byte is a parity bit,
//  so we must indicate a KeyLength of 192, which includes
//  the parity bits.
crypt.KeyLength = [NSNumber numberWithInt:192];

//  The padding scheme determines the contents of the bytes
//  that are added to pad the result to a multiple of the
//  encryption algorithm's block size.  3DES has a block
//  size of 8 bytes, so encrypted output is always
//  a multiple of 8.
crypt.PaddingScheme = [NSNumber numberWithInt:0];

//  EncodingMode specifies the encoding of the output for
//  encryption, and the input for decryption.
//  It may be "hex", "url", "base64", or "quoted-printable".
crypt.EncodingMode = @"hex";

//  An initialization vector is required if using CBC or CFB modes.
//  ECB mode does not use an IV.
//  The length of the IV is equal to the algorithm's block size.
//  It is NOT equal to the length of the key.
NSString *ivHex;
ivHex = @"0001020304050607";
[crypt SetEncodedIV: ivHex encoding: @"hex"];

//  The secret key must equal the size of the key.  For
//  3DES, the key must be 24 bytes (i.e. 192-bits).
NSString *keyHex;
keyHex = @"000102030405060708090A0B0C0D0E0F0001020304050607";
[crypt SetEncodedKey: keyHex encoding: @"hex"];

//  Encrypt a string...
//  The input string is 44 ANSI characters (i.e. 44 bytes), so
//  the output should be 48 bytes (a multiple of 8).
//  Because the output is a hex string, it should
//  be 96 characters long (2 chars per byte).
NSString *encStr;
encStr = [crypt EncryptStringENC: @"The quick brown fox jumps over the lazy dog."];
[strOutput appendString: encStr];
[strOutput appendString: @"\n"];

//  Now decrypt:
NSString *decStr;
decStr = [crypt DecryptStringENC: encStr];
[strOutput appendString: decStr];
[strOutput appendString: @"\n"];

self.mainTextField.stringValue = strOutput;