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https://github.com/iosdevzone/IDZSwiftCommonCrypto

A wrapper for Apple's Common Crypto library written in Swift.
https://github.com/iosdevzone/IDZSwiftCommonCrypto

Last synced: 3 months ago
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A wrapper for Apple's Common Crypto library written in Swift.

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# IDZSwiftCommonCrypto 

[![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage) [![Build Status](https://travis-ci.org/iosdevzone/IDZSwiftCommonCrypto.svg?branch=master)](https://travis-ci.org/iosdevzone/IDZSwiftCommonCrypto) [![Coverage Status](https://coveralls.io/repos/iosdevzone/IDZSwiftCommonCrypto/badge.svg?branch=master&service=github)](https://coveralls.io/github/iosdevzone/IDZSwiftCommonCrypto?branch=master)



A Swift wrapper for Apple's `CommonCrypto` library.



IDZSwiftCommonCrypto works with both CocoaPods and Cathage. For more details on how to install it into your projects see [INSTALL.md](INSTALL.md)



**If you are using CococaPods you must use `pod cache clean IDZSwiftCommonCrypto --all` after you upgrade Xcode. This is needed to avoid stale module maps being used from the CocoaPods cache. Removing your Podfile.lock and Pods directory is not sufficient.**



IDZSwiftCommonCrypto provides the following classes:



* `Digest` for calculating message digests,

* `HMAC` for calculating Hash-based Message Authentication Codes,

* `Cryptor` for encrypting and decrypting bounded buffers,

* `StreamCryptor` for encrypting and decrypting streaming information, and

* `PBKDF` for deriving key material from a password or passphrase.



Which Release to Use

--------------------

Which version you use depends on which version of Xcode and Swift you are currently using. Please refer to the list below:



* 0.7.4 -- Xcode 7.3.1, Swift 2.2

* 0.8.0 -- Xcode 7.3.1, Swift 2.2, with additional APIs for `CCMode`

* 0.8.3 -- Xcode 8.0, Swift 2.3

* 0.9.x -- Xcode 8.0, Swift 3.0

* 0.10.x -- Xcode 9.0, Swift 4.0

* 0.11.x -- Xcode 10.0, Swift 4.2

* 0.12.x -- Xcode 10.2, Swift 5.0

* 0.13.x -- Xcode 11.0, Swift 5.1, iOS 13.0



Using `Digest`

--------------



To calculate a message digest you create an instance of `Digest`, call `update` one or more times with the data over which the digest is being calculated and finally call `final` to obtain the digest itself.



The `update` method can take a `String`

```swift

let  s = "The quick brown fox jumps over the lazy dog."

var md5s2 : Digest = Digest(algorithm:.MD5)

md5s2.update(s)

let digests2 = md5s2.final()



// According to Wikipedia this should be

// e4d909c290d0fb1ca068ffaddf22cbd0

hexStringFromArray(digests2)

assert(digests2 == arrayFromHexString("e4d909c290d0fb1ca068ffaddf22cbd0"))

```

or an array of `UInt8` elements:

```swift

let b : [UInt8] = 

[0x54,0x68,0x65,0x20,0x71,0x75,0x69,0x63,

0x6b,0x20,0x62,0x72,0x6f,0x77,0x6e,0x20,

0x66,0x6f,0x78,0x2e]

var md5s1 : Digest = Digest(algorithm:.MD5)

md5s1.update(b)

let digests1 = md5s1.final()

```



If you only have a single buffer you can simply write

```swift

  var digests3 = Digest(algorithm: .md5).update(b)?.final() // digest is of type [UInt8]?

```

or 

```swift

  var digests4 = Digest(algorithm: .md5).update(s)?.final() // digest is of type [UInt8]?

```



### Supported Algorithms

The `Digest` class supports the following algorithms:



* `.md2` 

* `.md4` 

* `.md5` 

* `.sha1` 

* `.sha224` 

* `.sha256`

* `.sha384`

* `.sha512`



Using `HMAC`

------------



Calculating a keyed-Hash Message Authentication Code (HMAC) is very similar to calculating a message digest, except that the initialization routine now takes a key as well as an algorithm parameter.



```swift

var keys5 = arrayFrom(hexString: "0102030405060708090a0b0c0d0e0f10111213141516171819")

var datas5 : [UInt8] = Array(count:50, repeatedValue:0xcd)

var expecteds5 = arrayFrom(hexString: "4c9007f4026250c6bc8414f9bf50c86c2d7235da")

var hmacs5 = HMAC(algorithm:.sha1, key:keys5).update(datas5)?.final()



// RFC2202 says this should be 4c9007f4026250c6bc8414f9bf50c86c2d7235da

let expectedRFC2202 = arrayFrom(hexString: "4c9007f4026250c6bc8414f9bf50c86c2d7235da")

assert(hmacs5! == expectedRFC2202)

```

### Supported Algorithms

* `.md5`

* `.sha1`

* `.sha224`

* `.sha256`

* `.sha384`

* `.sha512`



## Using `Cryptor`



```swift

let algorithm = Cryptor.Algorithm.aes

var iv = try! Random.generateBytes(byteCount: algorithm.blockSize())

var key = arrayFrom(hexString: "2b7e151628aed2a6abf7158809cf4f3c")

var plainText = "The quick brown fox jumps over the lazy dog. The fox has more or less had it at this point."



var cryptor = Cryptor(operation:.encrypt, algorithm:algorithm, options:.PKCS7Padding, key:key, iv:iv)

var cipherText = cryptor.update(plainText)?.final()



cryptor = Cryptor(operation:.decrypt, algorithm:algorithm, options:.PKCS7Padding, key:key, iv:iv)

var decryptedPlainText = cryptor.update(cipherText!)?.final()

var decryptedString = String(bytes: decryptedPlainText!, encoding: .utf8)

decryptedString

assert(decryptedString == plainText)

```



### Supported Algorithms

* `.AES`

* `.DES` 

* `.TripleDES` 

* `.CAST` 

* `.RC2` 

* `.Blowfish`



## Using `StreamCryptor`



To encrypt a large file or a network stream use `StreamCryptor`. The `StreamCryptor` class does not accumulate the encrypted or decrypted data, instead each call to `update` produces an output buffer. 



The example below shows how to use `StreamCryptor` to encrypt and decrypt an image file.

```swift

func crypt(sc : StreamCryptor,  inputStream: InputStream, outputStream: OutputStream, bufferSize: Int) -> (bytesRead: Int, bytesWritten: Int)

{

    var inputBuffer = Array(repeating:0, count:1024)

    var outputBuffer = Array(repeating:0, count:1024)



    var cryptedBytes : Int = 0

    var totalBytesWritten = 0

    var totalBytesRead = 0

    while inputStream.hasBytesAvailable

    {

        let bytesRead = inputStream.read(&inputBuffer, maxLength: inputBuffer.count)

        totalBytesRead += bytesRead

        let status = sc.update(bufferIn: inputBuffer, byteCountIn: bytesRead, bufferOut: &outputBuffer, byteCapacityOut: outputBuffer.count, byteCountOut: &cryptedBytes)

        assert(status == Status.success)

        if(cryptedBytes > 0)

        {

            let bytesWritten = outputStream.write(outputBuffer, maxLength: Int(cryptedBytes))

            assert(bytesWritten == Int(cryptedBytes))

            totalBytesWritten += bytesWritten

        }

    }

    let status = sc.final(bufferOut: &outputBuffer, byteCapacityOut: outputBuffer.count, byteCountOut: &cryptedBytes)    

    assert(status == Status.success)

    if(cryptedBytes > 0)

    {

        let bytesWritten = outputStream.write(outputBuffer, maxLength: Int(cryptedBytes))

        assert(bytesWritten == Int(cryptedBytes))

        totalBytesWritten += bytesWritten

    }

    return (totalBytesRead, totalBytesWritten)

}



let imagePath = Bundle.main.path(forResource: "Riscal", ofType:"jpg")!

let tmp = NSTemporaryDirectory() as NSString

let encryptedFilePath = "\(tmp)/Riscal.xjpgx"

var decryptedFilePath = "\(tmp)/RiscalDecrypted.jpg"



// Prepare the input and output streams for the encryption operation

guard let imageInputStream = InputStream(fileAtPath: imagePath) else {

    fatalError("Failed to initialize the image input stream.")

}

imageInputStream.open()

guard let  encryptedFileOutputStream = OutputStream(toFileAtPath: encryptedFilePath, append:false) else

{

    fatalError("Failed to open output stream.")

}

encryptedFileOutputStream.open()



// Generate a new, random initialization vector

let initializationVector = try! Random.generateBytes(byteCount: algorithm.blockSize())



// A common way to communicate the initialization vector is to write it at the beginning of the encrypted data.

let bytesWritten = encryptedFileOutputStream.write(initializationVector, maxLength: initializationVector.count)



// Now write the encrypted data

var sc = StreamCryptor(operation:.encrypt, algorithm:algorithm, options:.PKCS7Padding, key:key, iv:initializationVector)

guard  bytesWritten == initializationVector.count else

{

    fatalError("Failed to write initialization vector to encrypted output file.")

}

let outputResult = crypt(sc: sc, inputStream: imageInputStream, outputStream: encryptedFileOutputStream, bufferSize: 1024)

encryptedFileOutputStream.close()

outputResult



// Uncomment this line to verify that the file is encrypted

//var encryptedImage = NSImage(contentsOfFile:encryptedFile)



// Prepare the input and output streams for the decryption operation

guard let encryptedFileInputStream = InputStream(fileAtPath: encryptedFilePath) else

{

    fatalError("Failed to open the encrypted file for input.")

}

encryptedFileInputStream.open()

guard let decryptedFileOutputStream = OutputStream(toFileAtPath: decryptedFilePath, append:false) else {

    fatalError("Failed to open the file for the decrypted output file.")

}

decryptedFileOutputStream.open()



// Read back the initialization vector.

var readbackInitializationVector = Array(repeating: 0, count: algorithm.blockSize())

let bytesRead = encryptedFileInputStream.read(&readbackInitializationVector, maxLength: readbackInitializationVector.count)



// Uncomment this to verify that we did indeed read back the initialization vector.

//assert(readbackInitializationVector == initializationVector)



// Now use the read back initialization vector (along with the key) to

sc = StreamCryptor(operation:.decrypt, algorithm:algorithm, options:.PKCS7Padding, key:key, iv:readbackInitializationVector)

let inputResult = crypt(sc: sc, inputStream: encryptedFileInputStream, outputStream: decryptedFileOutputStream, bufferSize: 1024)



// Uncomment this to verify that decrypt operation consumed all the encrypted data

// and produced the correct number of bytes of plaintext output.

//assert(inputResult.bytesRead == outputResult.bytesWritten && inputResult.bytesWritten == outputResult.bytesRead)



var image = NSImage(named:"Riscal.jpg")

var decryptedImage = NSImage(contentsOfFile:decryptedFilePath)

decryptedImage



```



## Using `PBKDF` 



The `PBKDF` class provides a method of deriving keys from a user password. 

The following example derives a 20-byte key:



```swift

let keys6 = PBKDF.deriveKey("password", salt: "salt", prf: .SHA1, rounds: 1, derivedKeyLength: 20)

// RFC 6070 - Should derive 0c60c80f961f0e71f3a9b524af6012062fe037a6

let expectedRFC6070 = arrayFrom(hexString: "0c60c80f961f0e71f3a9b524af6012062fe037a6")

assert(keys6 == expectedRFC6070)

```

### Supported Pseudo-Random Functions

* `.sha1`

* `.sha224` 

* `.sha256` 

* `.sha384` 

* `.sha512`