CryptoSwift

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

Table of Contents

• Requirements
• Features
• Contribution
• Installation
• Swift versions
• Usage
• Author
• License
• Changelog

Requirements

Good mood

Features

• Easy to use
• Convenient extensions for String and Data
• Support for incremental updates (stream, ...)
• iOS, macOS, AppleTV, watchOS, Linux support

Hash (Digest)

• MD5
• SHA1
• SHA224
• SHA256
• SHA384
• SHA512
• SHA3

Cyclic Redundancy Check (CRC)

• CRC32
• CRC16

Cipher

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

Message authenticators

• Poly1305
• HMAC MD5, SHA1, SHA256

Cipher block mode

• Electronic codebook (ECB)
• Cipher-block chaining (CBC)
• Propagating Cipher Block Chaining (PCBC)
• Cipher feedback (CFB)
• Output Feedback (OFB)
• Counter (CTR)

Password-Based Key Derivation Function

• PBKDF1 (Password-Based Key Derivation Function 1)
• PBKDF2 (Password-Based Key Derivation Function 2)

Data padding

• PKCS#7
• Zero padding
• NoPadding

Why

Why? Because I can.

Contribution

For the latest version, please check develop branch. Changes from this branch will be merged into the master branch at some point.

• If you want to contribute, submit a pull request against a development develop branch.
• If you found a bug, open an issue.
• If you have a feature request, open an issue.

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

It is recommended to enable Whole-Module Optimization to gain better performance. Non-optimized build results in significantly worse performance.

Embedded Framework

Embedded frameworks require a minimum deployment target of iOS 8 or OS X Mavericks (10.9). Drag the CryptoSwift.xcodeproj file into your Xcode project, and add appropriate framework as a dependency to your target. Now select your App and choose the General tab for the app target. Find Embedded Binaries and press "+", then select CryptoSwift.framework (iOS, OS X, watchOS or tvOS)

Sometimes "embedded framework" option is not available. In that case, you have to add new build phase for the target

iOS, macOS, watchOS, tvOS

In the project, you'll find single scheme for all platforms:

• CryptoSwift

Swift versions support

• Swift 1.2: branch swift12 version <= 0.0.13
• Swift 2.1: branch swift21 version <= 0.2.3
• Swift 2.2, 2.3: branch swift2 version <= 0.5.2
• Swift 3.1, branch master
• Swift 3.2, branch develop
• Swift 4.0, branch swift4

CocoaPods

You can use CocoaPods.

platform :ios, '8.0'
use_frameworks!

target 'MyApp' do
  pod 'CryptoSwift'
end

or for newest version from specified branch of code:

pod 'CryptoSwift', :git => "https://github.com/krzyzanowskim/CryptoSwift", :branch => "master"

Bear in mind that CocoaPods will build CryptoSwift without Whole-Module Optimization that my impact performance. You can change it manually after installation, or use cocoapods-wholemodule plugin.

Carthage

You can use Carthage. Specify in Cartfile:

github "krzyzanowskim/CryptoSwift"

Run carthage to build the framework and drag the built CryptoSwift.framework into your Xcode project. Follow build instructions

Swift Package Manager

You can use Swift Package Manager and specify dependency in Package.swift by adding this:

.Package(url: "https://github.com/krzyzanowskim/CryptoSwift.git", majorVersion: 0)

See: Package.swift - manual

Usage

• Basics (data types, conversion, ...)
• Digest (MD5, SHA...)
• Message authenticators (HMAC...)
• Password-Based Key Derivation Function (PBKDF2, ...)
• Data Padding
• ChaCha20
• Rabbit
• Blowfish
• Advanced Encryption Standard (AES)

also check Playground

Basics

import CryptoSwift

CryptoSwift uses array of bytes aka Array<UInt8> as a base type for all operations. Every data may be converted to a stream of bytes. You will find convenience functions that accept String or NSData, and it will be internally converted to the array of bytes.

Data types conversion

For you convenience CryptoSwift provides two functions to easily convert array of bytes to NSData and another way around:

Data from bytes:

let data = Data(bytes: [0x01, 0x02, 0x03])

Data to Array<UInt8>

let bytes = data.bytes                     // [1,2,3]

Hexadecimal encoding:

let bytes = Array<UInt8>(hex: "0x010203")  // [1,2,3]
let hex   = bytes.toHexString()            // "010203"

Build bytes out of String

let bytes = Array("string".utf8)

Also... check out helpers that work with Base64 encoded data:

"aPf/i9th9iX+vf49eR7PYk2q7S5xmm3jkRLejgzHNJs=".decryptBase64ToString(cipher)
"aPf/i9th9iX+vf49eR7PYk2q7S5xmm3jkRLejgzHNJs=".decryptBase64(cipher)
bytes.toBase64()

Calculate Digest

Hashing a data or array of bytes (aka Array<UInt8>)

/* Hash struct usage */
let bytes:Array<UInt8> = [0x01, 0x02, 0x03]
let digest = input.md5()
let digest = Digest.md5(bytes)

let data = Data(bytes: [0x01, 0x02, 0x03])

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

do {
    var digest = MD5()
    let partial1 = try digest.update(withBytes: [0x31, 0x32])
    let partial2 = try digest.update(withBytes: [0x33])
    let result = try digest.finish()
} catch { }

Hashing a String and printing result

let hash = "123".md5()

Calculate CRC

bytes.crc16()
data.crc16()

bytes.crc32()
data.crc32()

Message authenticators

// Calculate Message Authentication Code (MAC) for message
let key:Array<UInt8> = [1,2,3,4,5,6,7,8,9,10,...]

try Poly1305(key: key).authenticate(bytes)
try HMAC(key: key, variant: .sha256).authenticate(bytes)

Password-Based Key Derivation Functions

let password: Array<UInt8> = Array("s33krit".utf8)
let salt: Array<UInt8> = Array("nacllcan".utf8)

try PKCS5.PBKDF2(password: password, salt: salt, iterations: 4096, variant: .sha256).calculate()

Data Padding

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.

PKCS7().add(to: bytes, blockSize: AES.blockSize)

Working with Ciphers

ChaCha20

let encrypted = try ChaCha20(key: key, iv: iv).encrypt(message)
let decrypted = try ChaCha20(key: key, iv: iv).decrypt(encrypted)

Rabbit

let encrypted = try Rabbit(key: key, iv: iv).encrypt(message)
let decrypted = try Rabbit(key: key, iv: iv).decrypt(encrypted)

Blowfish

let encrypted = try Blowfish(key: key, iv: iv, blockMode: .CBC, padding: PKCS7()).encrypt(message)
let decrypted = try Blowfish(key: key, iv: iv, blockMode: .CBC, padding: PKCS7()).decrypt(encrypted)

AES

Notice regarding padding: Manual padding of data is optional, and CryptoSwift is using PKCS7 padding by default. If you need manually disable/enable padding, you can do this by setting parameter for AES class

Variant of AES encryption (AES-128, AES-192, AES-256) depends on given key length:

• AES-128 = 16 bytes
• AES-192 = 24 bytes
• AES-256 = 32 bytes

AES-256 example

try AES(key: [1,2,3,...,32], iv: [1,2,3,...,16], blockMode: .CBC, padding: PKCS7())

All at once

do {
    let aes = try AES(key: "passwordpassword", iv: "drowssapdrowssap") // aes128
    let ciphertext = try aes.encrypt(Array("Nullam quis risus eget urna mollis ornare vel eu leo.".utf8))
} catch { }

Incremental updates

Incremental operations use instance of Cryptor and encrypt/decrypt one part at a time, this way you can save on memory for large files.

do {
    var encryptor = try AES(key: "passwordpassword", iv: "drowssapdrowssap").makeEncryptor()

    var ciphertext = Array<UInt8>()
    // aggregate partial results
    ciphertext += try encryptor.update(withBytes: Array("Nullam quis risus ".utf8))
    ciphertext += try encryptor.update(withBytes: Array("eget urna mollis ".utf8))
    ciphertext += try encryptor.update(withBytes: Array("ornare vel eu leo.".utf8))
    // finish at the end
    ciphertext += try encryptor.finish()

    print(ciphertext.toHexString())
} catch {
    print(error)
}

See Playground for sample code that work with stream.

AES Advanced usage

let input: Array<UInt8> = [0,1,2,3,4,5,6,7,8,9]

let key: Array<UInt8> = [0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00]
let iv: Array<UInt8> = AES.randomIV(AES.blockSize)

do {
    let encrypted = try AES(key: key, iv: iv, blockMode: .CBC, padding: PKCS7()).encrypt(input)
    let decrypted = try AES(key: key, iv: iv, blockMode: .CBC, padding: PKCS7()).decrypt(encrypted)
} catch {
    print(error)
}    

AES without data padding

let input: Array<UInt8> = [0,1,2,3,4,5,6,7,8,9]
let encrypted: Array<UInt8> = try! AES(key: "secret0key000000", iv:"0123456789012345", blockMode: .CBC, padding: NoPadding()).encrypt(input)

Using convenience extensions

let plain = Data(bytes: [0x01, 0x02, 0x03])
let encrypted = try! plain.encrypt(ChaCha20(key: key, iv: iv))
let decrypted = try! encrypted.decrypt(ChaCha20(key: key, iv: iv))

Author

CryptoSwift is owned and maintained by Marcin Krzyżanowski

You can follow me on Twitter at @krzyzanowskim for project updates and releases.

License

Copyright (C) 2014-2017 Marcin Krzyżanowski [email protected] 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.

Changelog

See CHANGELOG file.