Xor Reader/Writer example

xor.go

package main

import (
	"fmt"
	"io"
	"os"
)

type XorWriter struct {
	w   io.Writer
	key []byte
}

func (xw *XorWriter) Write(p []byte) (int, error) {
	pXored := make([]byte, len(p), len(p))
	for k, v := range p {
		pXored[k] = v ^ xw.key[k%len(xw.key)]
	}
	return xw.w.Write(pXored)
}

type XorReader struct {
	r   io.Reader
	key []byte
}

func (xr *XorReader) Read(p []byte) (int, error) {
	n, err := xr.r.Read(p)
	for i := 0; i < n; i++ {
		p[i] = p[i] ^ xr.key[i % len(xr.key)]
	}
	return n, err
}

func main() {

	//xr := XorReader{os.Stdin, 42}
	//out := make([]byte, 100)
	//xr.Read(out)
	//fmt.Print(string(out))
	f, _ := os.Create("test.txt")
	defer f.Close()
	text := []byte("Hello world")

	xw := XorWriter{f, []byte{42, 41, 40}}
	xw.Write(text)


	f1, _ := os.Open("test.txt")
	xr := XorReader{f1, []byte{42, 41, 40}}
	out := make([]byte, 100)
	xr.Read(out)
	fmt.Println(string(out))



}