Hash-Key Message Authentication Code (HMAC)

main.go

package main

import (
	"crypto/hmac"
	"crypto/sha512"
  "crypto/md5"
	"encoding/base64"
	"fmt"
  "hash"
)

func signString(stringToSign []byte, sharedSecret []byte, method string) []byte {
  var h hash.Hash

  if(method == "md5") {
    h = hmac.New(md5.New, sharedSecret)
  } else if (method == "sha512") {
    h = hmac.New(sha512.New, sharedSecret)
  }

	h.Write(stringToSign)
	return h.Sum(nil)
}

func main() {
	signature := signString([]byte("data"), []byte("secret"), "md5")
	fmt.Println(fmt.Sprintf("signature=%s",
    base64.URLEncoding.EncodeToString(signature)))
}