cantecim/fclblowfish

An Objective-C Blowfish library

FclBlowfish

An Objective-C Blowfish Implementation

• Supports EBC and CBC mode
• Supports padding RFC and Zero padding
• Works compatible with PHP's Mcrypt
• Originally coded for iOS SDK. It may work also for OS X SDK

You easily find out how to use the library.

• Import it.
• Create an instance.
• Set IV and Key then call prepare
• Do encryption or decryption

Feel free to contribute

How to Use

Encrypt

FclBlowfish *bf = [[FclBlowfish alloc] init];
bf.Key = @"37501370571307510";
bf.IV = @"asdf";
[bf prepare];
NSLog(@"encrypt %@", [bf encrypt:@"Hi there" withMode:modeCBC withPadding:paddingRFC]);

Decrypt

bf = [[FclBlowfish alloc] init];
bf.Key = @"37501370571307510";
bf.IV = @"asdf";
[bf prepare];    NSLog(@"encrypt %@", [bf decrypt:[bf encrypt:@"Hi there" withMode:modeCBC withPadding:paddingRFC] withMode:modeCBC withPadding:paddingRFC]);

Properties

Property	Description	Restrictions	Suggestions
Key	This is the cryption key use it as salt	Must use 1 byte characters(ASCII table)	You can use md5 hashed text in hexadecimal format it will be 256 bit size then you can add extra 24 characters(192 bit) to reach 448 bit
IV	This is the initialization vector	No restricton	You need to implement an algrotihm for storing this in final crypted text. Simply you can add base64 encoded iv to end of crypted text. So your server(decryptor) can extract it from the text and use it for decryption. You must do this in order to use unique IV for all crypted text. This way no one can crack it even they know the key you used

Troubleshooting

• If you use mcrypt_create_iv to generate iv string you may have problems decrypting in ios. Take a look at this issue : #1

To-Do(s)

Developed By

• Can Tecim(Original Author) - [email protected]

License

Copyright 2013 Can Tecim

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

fclblowfish's Issues

crash in removePad Method

• (NSString *)removePad:(NSString *)plain
  {
  //need add code
  if (![plain length])
  {
  return nil;
  }
  NSUInteger paddedlen = [plain characterAtIndex:[plain length] - 1]; //When plain = @"" shows crash

  .......
  }

How to work with PHP

Hi There,

I have the encryption and decryption code in PHP working fine, but I cannot decrypt or encrypt in iOS using this lib.

My encryption and decryption code in PHP are:

Decrypt

$initializationVectorSize = mcrypt_get_iv_size(MCRYPT_BLOWFISH, 'ecb');
$initializationVector = mcrypt_create_iv($initializationVectorSize, MCRYPT_RAND);

$valor = $_GET['v'];
$valor = base64_decode($valor);
$valor = mcrypt_decrypt(MCRYPT_BLOWFISH, 'mYk3yS3c', $valor, 'ecb', $initializationVector);
$valor = trim($valor, " \x00..\x1F");
print 'Valor: ' . $valor;

Encrypt

$initializationVectorSize = mcrypt_get_iv_size(MCRYPT_BLOWFISH, 'ecb');
$initializationVector = mcrypt_create_iv($initializationVectorSize, MCRYPT_RAND);

$v = mcrypt_encrypt(MCRYPT_BLOWFISH, 'mYk3yS3c', $v, 'ecb', $initializationVector);
print base64_encode($v);

one example is the following encrypted string:
cCVGRSYKtjQhyaLfn+lumQ==

In my PHP code it decrypts fines, with the result "21988882121" (without quotes).

But in my decryption code on iOS, I don't know how to properly initialize the vector following the PHP standard.

FclBlowfish *bf = [[FclBlowfish alloc] init];
bf.Key = @"mYk3yS3c";
bf.IV = @"";
[bf prepare];

NSLog(@"decrypt %@", [bf decrypt:@"d5NXWox77nXb0InI+zP98Q==" withMode:modeEBC withPadding:paddingZero]);

Any help is much appreciated!

Thanks!