StreamKit

This open-source Swift library offers a comprehensive collection of cryptographic algorithms. These ciphers can be structured into chains, facilitating the seamless flow of output from one cipher stream to another. This architecture enables concurrent tasks, such as encrypting data while writing the encrypted result to a file. Integrate "StreamKit" into your projects to efficiently utilize these cryptographic functionalities.

The available streams

• FileStream
• GzipStream
• AesStream
• Salsa20Stream
• ChaCha20Stream
• TwoFishStream

How to add the library to a project

In the Xcode press File -> Add Packages -> In the search field insert https://github.com/iharkatkavets/StreamKit.git. It might require to setup GitHub Account in the Xcode

How to use the library in the project

First import the library

import StreamKit

How to read a file using FileInputStream

let fileURL: URL = ...
guard let fileInputStream = FileInputStream(with: fileURL) else {
        return
}
try fileInputStream.open()

let fileContent: Data = try fileInputStream.readToEnd()

// or read chunk by chunk
let tmpBufferLen = 1<<16 // 65KB buffer
var tmpBuffer = Array<UInt8>(repeating: 0, count: tmpBufferLen)
while fileInputStream.hasBytesAvailable {
        let readLen = fileInputStream.read(&tmpBuffer, maxLength: tmpBufferLen)
        // process tmpBuffer
}
        
inputFileStream.close()

How to write to a file using FileOutputStream

let fileURL: URL = ...
guard let fileOutputStream = FileOutputStream(with: fileURL) else {
        return
}
try fileOutputStream.open()

// write string to a file      
try fileOutputStream.write("Hello world", ofEncoding: .utf8)

// or write data to a file
try fileOutputStream.write(Data([0,1,2,3]))

// or write some buffer to a file
let tmpBufferLen = 1<<16 // 65KB buffer
var tmpBuffer = Array<UInt8>(repeating: 0, count: tmpBufferLen)
try compressingStream.write(tmpBuffer, length: readLen)

try fileOutputStream.close()

How to perform encrypting using AesOutputStream

...
let encryptingStream = AesOutputStream(writingTo: fileOutputStream,
                                                   key: key,
                                                   iv: iv)
try encryptingStream.open()
                    
try encryptingStream.write("Hello world", ofEncoding: .utf8)
try encryptingStream.close()
...

How to perform decrypting using AesInputStream

...
let decryptingStream = AesInputStream(readingFrom: inputFileStream,
                                              key: key,
                                              iv: iv)
try decryptingStream.open()
        
let tmpBufferLen = 1<<16 // 65KB buffer
var tmpBuffer = Array<UInt8>(repeating: 0, count: tmpBufferLen)
while decryptingStream.hasBytesAvailable {
        let readLen = try decryptingStream.read(&tmpBuffer, maxLength: tmpBufferLen)
        // process buffer
}
        
decryptingStream.close()
...

How to perform encrypting using Salsa20OutputStream

...
let encryptingStream = Salsa20OutputStream(writingTo: fileOutputStream,
                                                   key: key,
                                                   iv: iv)
try encryptingStream.open()
                    
try encryptingStream.write("Hello world", ofEncoding: .utf8)
try encryptingStream.close()
...

How to perform decrypting using Salsa20InputStream

...
let decryptingStream = Salsa20InputStream(readingFrom: inputFileStream,
                                              key: key,
                                              iv: iv)
try decryptingStream.open()
        
let decryptedData = try decryptingStream.readToEnd()
        
decryptingStream.close()
...

How to perform encrypting using ChaCha20OutputStream

...
let encryptingStream = ChaCha20OutputStream(writingTo: fileOutputStream,
                                                   key: key,
                                                   iv: iv)
try encryptingStream.open()
                    
try encryptingStream.write("Hello world", ofEncoding: .utf8)
try encryptingStream.close()
...

How to perform decrypting using ChaCha20InputStream

...
let decryptingStream = ChaCha20InputStream(readingFrom: inputFileStream,
                                              key: key,
                                              iv: iv)
try decryptingStream.open()
        
let decryptedData = try decryptingStream.readToEnd()
        
decryptingStream.close()
...

How to perform encrypting using TwoFishOutputStream

...
let encryptingStream = TwoFishOutputStream(writingTo: fileOutputStream,
                                                   key: key,
                                                   iv: iv)
try encryptingStream.open()
                    
try encryptingStream.write("Hello world", ofEncoding: .utf8)
try encryptingStream.close()
...

How to perform decrypting using TwoFishInputStream

...
let decryptingStream = TwoFishInputStream(readingFrom: inputFileStream,
                                              key: key,
                                              iv: iv)
try decryptingStream.open()
        
let tmpBufferLen = 1<<16 // 65KB buffer
var tmpBuffer = Array<UInt8>(repeating: 0, count: tmpBufferLen)
while decryptingStream.hasBytesAvailable {
        let readLen = try decompressingStream.read(&tmpBuffer, maxLength: tmpBufferLen)
        // process or store bytes in `tmpBuffer`
}
        
decryptingStream.close()
...

How to use it

For example it's possible to encrypt some data and simulteniously write the encrypted result to a file.

let secureFileURL: URL = ...
let fileHandle = try! FileHandle(forWritingTo: secureFileURL)
let outputFileStream = FileOutputStream(with: fileHandle)
try outputFileStream.open()
        
let encryptingStream = Salsa20OutputStream(writingTo: outputFileStream,
                                            key: key,
                                            iv: iv)
try encryptingStream.open()
                
let tmpBufferLen = 1<<16 
var tmpBuffer = Array<UInt8>(repeating: 0, count: tmpBufferLen)
while inputFileStream.hasBytesAvailable {
  let readLen = inputFileStream.read(&tmpBuffer, maxLength: tmpBufferLen)
  try encryptingStream.write(tmpBuffer, length: readLen)
}
        
try encryptingStream.close()
try outputFileStream.close()

Another example demonstrate reading the encrypted file

let inputFileStream = FileInputStream(withFileHandle: try! FileHandle(forReadingFrom: secureFileURL))
try inputFileStream.open()
        
let bufferingStream = BufferOutputStream()
try bufferingStream.open()
        
let decryptingStream = Salsa20InputStream(readingFrom: inputFileStream,
                                                  key: key,
                                                  iv: iv)
try decryptingStream.open()
        
let tmpBufferLen = 1<<16 // 65KB buffer
var tmpBuffer = Array<UInt8>(repeating: 0, count: tmpBufferLen)
while decryptingStream.hasBytesAvailable {
  let readLen = try decryptingStream.read(&tmpBuffer, maxLength: tmpBufferLen)
  try bufferingStream.write(tmpBuffer, length: readLen)
}
        
decryptingStream.close()
try bufferingStream.close()
inputFileStream.close()

Sponsorship

The library was developed in collaboration with KeePassium