CryptoSwift/README.md

#CryptoSwift Crypto related functions and helpers for Swift implemented in Swift. (#PureSwift)

##Requirements Good mood

##Features

• Easy to use
• Convenience extensions

###What implemented?

Hash

• MD5
• SHA1
• SHA224
• SHA256
• SHA384
• SHA512
• CRC32 (well, kind of hash)

#####Cipher

• AES-128, AES-192, AES-256
• ChaCha20

#####Message authenticators

• Poly1305
• HMAC MD5, SHA1, SHA256

#####Cipher block mode

• Electronic codebook (ECB)
• Cipher-block chaining (CBC)
• Cipher feedback (CFB)

#####Data padding

• PKCS#7

###Why Why? Because I can.

##Installation

To install CryptoSwift, add it as a submodule to your project (on the top level project directory):

git submodule add https://github.com/krzyzanowskim/CryptoSwift.git

Then, drag the CryptoSwift.xcodeproj file into your Xcode project, and add CryptoSwift.framework as a dependency for your target.

#####iOS and OSX By default project is setup for iOS. You need to switch to OSX SDK manually see #8

##Usage

import CryptoSwift

Generally you should use CryptoSwift.Hash,CryptoSwift.Cipher enums or convenience extensions

Hash enum usage

/* Hash enum usage */
var data:NSData = NSData(bytes: [49, 50, 51] as [Byte], length: 3)
if let data = CryptoSwift.Hash.md5(data).calculate() {
    println(data.hexString)
}

Hashing a data

let hash = data.md5()
let hash = data.sha1()
let hash = data.sha224()
let hash = data.sha256()
let hash = data.sha384()
let hash = data.sha512()

let crc = data.crc32()

println(hash.hexString)

Hashing a String and printing result

if let hash = "123".md5() {
    println(hash)
}

Some content-encryption algorithms assume the input length is a multiple of k octets, where k is greater than one. For such algorithms, the input shall be padded

let paddedData = PKCS7(data: dataToEncrypt).addPadding(AES.blockSizeBytes())

Working with Ciphers

ChaCha20

let chacha20Encrypted = Cipher.ChaCha20(key: keyData, iv: ivData).encrypt(dataToEncrypt)
let decryptedChaCha20 = Cipher.ChaCha20(key: keyData, iv: ivData).decrypt(encryptedData)

AES

Padding plaintext data is required for most of the cases (unless message can be split into chunks of block size). Nonetheless explicit padding is optional and CryptoSwift will add padding when necessary. Removing padding is necessary after decryption if applied earlier (CryptoSwift can't decide if padding was applied earlier, this is up to you). For this reason the most convenient way is always add padding before encryption and remove after decryption, as described below:

// 1. Add padding
let paddedPlaintextData = PKCS7(data: plaintextData).addPadding(AES.blockSizeBytes())

// 2. Encrypt with key and random IV
let keyData = NSData.withBytes([0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00])
let ivData:NSData = Cipher.randomIV(keyData)
let encryptedData = Cipher.AES(key: keyData, iv: ivData, blockMode: .CBC).encrypt(paddedPlaintextData)

// or
let aes = AES(key: keyData, iv: ivData, blockMode: .CBC) // CBC is default
let encryptedData = aes?.encrypt(paddedData)

// 3. decrypt with key and IV
let decryptedPlaintextData = Cipher.AES(key: keyData, iv: ivData, blockMode: .CBC).decrypt(encryptedData)

// 4. remove padding ONLY IF applied earlier
let plaintextData = PKCS7(data: decryptedPlaintextData).removePadding() 

Using extensions

// convenience setup tuple
let setup = (key: keyData, iv: ivData)

let encrypted = dataToEncrypt.encrypt(Cipher.ChaCha20(setup))
let decrypted = encrypted.decrypt(Cipher.ChaCha20(setup))

Message authenticators

// Calculate Message Authentication Code (MAC) for message
let mac = Authenticator.Poly1305(key: key).authenticate(message)

##Contact Marcin Krzyżanowski @krzyzanowskim

##Licence

Copyright (C) 2014 Marcin Krzyżanowski marcin.krzyzanowski@gmail.com This software is provided 'as-is', without any express or implied warranty.

In no event will the authors be held liable for any damages arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:

• The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation is required.
• Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
• This notice may not be removed or altered from any source or binary distribution.