Triple DES Key creation example using CommonCrypto Library

gistfile1.m

#import <CommonCrypto/CommonKeyDerivation.h>
#import <CommonCrypto/CommonCryptor.h>

- (NSData *)derivedKeyFromPassword:(NSString*)password salt:(NSData*)saltData length:(NSUInteger)keyLength
{
  NSMutableData *derivedKey = [NSMutableData dataWithLength:keyLength];
  int result = CCKeyDerivationPBKDF(kCCPBKDF2,                          // algorithm
                                    password.UTF8String,                // password
                                    password.length,                    // passwordLength
                                    saltData.bytes,                     // salt
                                    saltData.length,                    // saltLen
                                    kCCPRFHmacAlgSHA256,                // PRF
                                    10000,                              // rounds
                                    derivedKey.mutableBytes,            // derivedKey
                                    keyLength);                         // derivedKeyLen

  if (result != kCCSuccess) {
    NSError *error = [NSError errorWithDomain:@"com.your_domain.your_project_name.your_class_name" code:result userInfo:nil];
    NSLog(@"error: %@", error);
    return nil;
  }
  return derivedKey;
}

- (NSData *)randomDataOfLength:(size_t)length
{
  NSMutableData *data = [NSMutableData dataWithLength:length];
  int result = SecRandomCopyBytes(kSecRandomDefault, length, data.mutableBytes);
  if (result != 0) return nil;
  return data;
}

- (void)tripleDesKeyCreation
{
  NSString *password = @"asdfQWER1234!@#$";
  NSUInteger keyLength = kCCKeySize3DES;
  NSUInteger saltLength = 8;
  
  NSData *saltData = [self randomDataOfLength:saltLength];

  NSData *derivedKey = [self derivedKeyFromPassword:password salt:saltData length:keyLength];
}