BlueCryptor

Swift cross-platform crypto library derived from IDZSwiftCommonCrypto.

Status

The current version has been updated for Swift 3.0 and includes new packaging. The API presented by this framework is NOT the same as the one presented by the original. It has been updated to conform to the Swift 3.0 API Guidelines.

This package is functionally complete and has all current relevant tests passing on both OS X and Linux.

Note: On OS X, BlueCryptor uses the Apple provided CommonCrypto library. On Linux, it uses libcrypto from OpenSSL.

Prerequisites

Swift

Swift Open Source swift-DEVELOPMENT-SNAPSHOT-2016-06-20-a toolchain (Minimum REQUIRED for latest release)

OS X

OS X 10.11.0 (El Capitan) or higher
Xcode Version 8.0 beta (8S128d) or higher using the above toolchain (Recommended)

Linux

Ubuntu 15.10 (or 14.04 but only tested on 15.10)
The Swift Open Source toolchains listed above

Build

To build Cryptor from the command line:

% cd <path-to-clone>
% swift build

Testing

To run the supplied unit tests for Cryptor from the command line:

% cd <path-to-clone>
% swift build
% swift test

Getting started

import Cryptor

API

Cryptor

The following code demonstrates encryption and decryption using AES single block CBC mode using optional chaining.

let key = CryptoUtils.byteArray(fromHex: "2b7e151628aed2a6abf7158809cf4f3c")
let iv = CryptoUtils.byteArray(fromHex: "00000000000000000000000000000000")
let plainText = CryptoUtils.byteArray(fromHex: "6bc1bee22e409f96e93d7e117393172a")

var textToCipher = plainText
if plainText.count % Cryptor.Algorithm.aes.blockSize != 0 {
	textToCipher = CryptoUtils.zeroPad(byteArray: plainText, blockSize: Cryptor.Algorithm.aes.blockSize)
}
let cipherText = Cryptor(operation: .encrypt, algorithm: .aes, options: .none, key: key, iv: iv).update(byteArray: textToCipher)?.final()
		
print(CryptoUtils.hexString(from: cipherText!))
		
let decryptedText = Cryptor(operation: .decrypt, algorithm: .aes, options: .none, key: key, iv: iv).update(byteArray: cipherText!)?.final()

print(CryptoUtils.hexString(from: decryptedText!))

Digest

The following example illustrates generating an MD5 digest from both a String and an instance of NSData.

let qbfBytes : [UInt8] = [0x54,0x68,0x65,0x20,0x71,0x75,0x69,0x63,0x6b,0x20,0x62,0x72,0x6f,0x77,0x6e,0x20,0x66,0x6f,0x78,0x20,0x6a,0x75,0x6d,0x70,0x73,0x20,0x6f,0x76,0x65,0x72,0x20,0x74,0x68,0x65,0x20,0x6c,0x61,0x7a,0x79,0x20,0x64,0x6f,0x67,0x2e]
let qbfString = "The quick brown fox jumps over the lazy dog."

// String...
let md5 = Digest(using: .md5)
md5.update(string: qfbString)
let digest = md5.final()

// NSData using optional chaining...
let qbfData = CryptoUtils.data(from: qbfBytes)
let digest = Digest(using: .md5).update(data: qbfData)?.final()

HMAC

The following demonstrates generating an SHA256 HMAC using byte arrays for keys and data.

let myKeyData = "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b"
let myData = "4869205468657265"
let key = CryptoUtils.byteArray(fromHex: myKeyData)
let data : [UInt8] = CryptoUtils.byteArray(fromHex: myData)

let hmac = HMAC(using: HMAC.Algorithm.sha256, key: key).update(byteArray: data)?.final()

Key Derivation

The following illustrates generating a key using a password, salt, number of rounds and a specified derived key length using the SHA1 algorithm. Then it shows how to generate a String from resultant key.

let password = "password"
let salt = salt
let rounds: UInt = 2
let derivedKeyLen = 20

let key = PBKDF.deriveKey(fromPassword: password, salt: salt, prf: .sha1, rounds: rounds, derivedKeyLength: derivedKeyLen)
ley keyString = CryptoUtils.hexString(from: key)

Random Byte Generation

The following demonstrates generating random bytes of a given length.

let numberOfBytes = 256*256
do {
	let randomBytes = try Random.generate(byteCount: numberOfBytes)
} catch {
  	print("Error generating random bytes")
}

Utilities

Cryptor also provides a set of data manipulation utility functions for conversion of data from various formats:

To byteArray ([UInt8])
- From hex string
- From UTF8 string
To NSData
- From hex string
- From byte array ([UInt8])
To NSString
- From byte array ([UInt8])
To hexList (String)
- From byte array ([UInt8])

Also provided are an API to pad a byte array ([UInt8]) such that it is an integral number of block size in bytes long.

func zeroPad(byteArray: [UInt8], blockSize: Int) -> [UInt8]
func zeroPad(string: String, blockSize: Int) -> [UInt8]

Restrictions

Due to an issue with API differences between the Foundation implementation on OS X versus the implementation on Linux, the following API usuage is not available on Linux. It remains available on OS X. Once the issue is resolved, this API usage will be available on both platforms. This API is an extension to NSData that allows generation of a digest from a previously populated NSData instance.

let shaShortBlock = "abc"
let sha224BlockOutput = "23097d223405d8228642a477bda255b32aadbce4bda0b3f7e36c9da7"
let sha256BlockOutput = "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad"
let sha384BlockOutput = "cb00753f45a35e8bb5a03d699ac65007272c32ab0eded1631a8b605a43ff5bed8086072ba1e7cc2358baeca134c825a7"
let sha512BlockOutput = "ddaf35a193617abacc417349ae20413112e6fa4e89a97ea20a9eeee64b55d39a2192992a274fc1a836ba3c23a3feebbd454d4423643ce80e2a9ac94fa54ca49f"
let theData: NSData = shaShortBlock.data(using:NSUTF8StringEncoding)!
XCTAssertEqual(theData.sha224, CryptoUtils.data(fromHex: sha224BlockOutput))
XCTAssertEqual(theData.sha256, CryptoUtils.data(fromHex: sha256BlockOutput))
XCTAssertEqual(theData.sha384, CryptoUtils.data(fromHex: sha384BlockOutput))
XCTAssertEqual(theData.sha512, CryptoUtils.data(fromHex: sha512BlockOutput))

These tests pass on OS X but will fail with the following error on Linux: This API not supported on Linux.

The following algorithms are not available on Linux since they are not supported by OpenSSL.

Digest: MD2, SHA1
HMAC: SHA1

In all cases, use of unsupported APIs or algorithms will result in a Swift fatalError(), terminating the program and should be treated as a programming error.

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