Golang crypto/rc4.NewCipher() function example

package crypto/rc4

NewCipher creates and returns a new Cipher. The key argument should be the RC4 key, at least 1 byte and at most 256 bytes.

Golang crypto/rc4.NewCipher() function usage example

 package main

 import (
 "crypto/rc4"
 "fmt"
 )

 func main() {

  key := []byte("123") // min 1 byte, max is 256 bytes!


  c, err := rc4.NewCipher(key)
  if err != nil {
 // this is the KeySizeError output if the key is less than 1 byte
 // or more than 256 bytes
 fmt.Println(err.Error) // KeySizeError
  }

  plaintext := []byte("Secret message")

  //encrypt
  encrypted := make([]byte, len(plaintext))
  c.XORKeyStream(encrypted, plaintext)
  fmt.Printf("[%s] encrypted to [%x] by rc4 crypto\n", plaintext, encrypted)

  c.Reset() // reset the key data just for fun

  //decrypt
  decrypted := make([]byte, len(encrypted))

  // we need to generate back the key because it was Reset above

  c, err = rc4.NewCipher(key)
  if err != nil {
 fmt.Println(err.Error)
  }

  c.XORKeyStream(decrypted, encrypted)
  fmt.Printf("[%x] decrypted to [%s] \n", encrypted, decrypted)

 }

Sample output :

go run cryptorc4.go

[Secret message] encrypted to [0095dcf080002496401070eb197e] by rc4 crypto

[0095dcf080002496401070eb197e] decrypted to [Secret message]

Reference :

http://golang.org/pkg/crypto/rc4/#NewCipher