(Objective-C) AES Encrypt String (utf-8 byte representation) and return Base64

Demonstrates how to AES encrypt the utf-8 byte representation of a string and return in base64 format.

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

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

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

crypt.CryptAlgorithm = @"aes";
crypt.CipherMode = @"cbc";
crypt.KeyLength = [NSNumber numberWithInt:256];
crypt.Charset = @"utf-8";
crypt.EncodingMode = @"base64";

NSString *ivHex = @"000102030405060708090A0B0C0D0E0F";
[crypt SetEncodedIV: ivHex encoding: @"hex"];
NSString *keyHex = @"000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F";
[crypt SetEncodedKey: keyHex encoding: @"hex"];

NSString *encryptedStr = [crypt EncryptStringENC: @"This is the original string"];
NSLog(@"%@",encryptedStr);

// Let's say we want to URL encode the base64 string..
crypt.CryptAlgorithm = @"none";
crypt.EncodingMode = @"url";
NSString *urlEncoded = [crypt EncryptStringENC: encryptedStr];
NSLog(@"%@",urlEncoded);

// Sample output:

//  q3fmgEqjqa9o//ZS6aPuh4Wtbrrxx/WOIQSKeVnesZg=
//  q3fmgEqjqa9o%2F%2FZS6aPuh4Wtbrrxx%2FWOIQSKeVnesZg%3D

// -------------------------------------------------------------------
// Now let's do the reverse...
// 

// We start with a string that is the binary encrypted data, base64 encoded, and then URL encoded.
NSString *encBase64Url = @"q3fmgEqjqa9o%2F%2FZS6aPuh4Wtbrrxx%2FWOIQSKeVnesZg%3D";

// We'll use the same crypt object.  If using a new instance of the crypt object,
// make sure *all* settings are identical:  the algorithm, cipher mode, key length, charset, encoding mode, IV, and secret key.

// Decode from URL...
crypt.CryptAlgorithm = @"none";
crypt.EncodingMode = @"url";
NSString *encBase64 = [crypt DecryptStringENC: urlEncoded];
NSLog(@"%@",encBase64);

// Now decrypt...
crypt.CryptAlgorithm = @"aes";
crypt.EncodingMode = @"base64";
NSString *originalStr = [crypt DecryptStringENC: encBase64];
NSLog(@"%@",originalStr);