(Objective-C) 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.

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#import <CkoCrypt2.h>
#import <NSString.h>

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

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

// 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 = @"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 = @"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 = [crypt EncryptStringENC: @"The quick brown fox jumps over the lazy dog."];
NSLog(@"%@",encStr);

// Now decrypt:
NSString *decStr = [crypt DecryptStringENC: encStr];
NSLog(@"%@",decStr);