Hash Example

main.go

// http://play.golang.org/p/YxTFqTxBPv

package main

import (
	"crypto/hmac"
	"crypto/rand"
	"crypto/sha512"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"time"
)

type BaseMessage struct {
	PublicKey string
	TimeStamp time.Time
	Nonce     string
	Verb      string
	Body      string
}

type SignedMessage struct {
	MessageInfo BaseMessage
	Hash        string
}

func (sm *SignedMessage) SetHash(privkey string) {
	jsonbody, _ := json.Marshal(sm.MessageInfo)
	key := []byte(privkey)
	h := hmac.New(sha512.New, key)
	h.Write([]byte(jsonbody))
	sm.Hash = base64.StdEncoding.EncodeToString(h.Sum(nil))
}
func main() {
	pubkey := "mbRgpR2eYAdJkhvrfwjlmMC+L/0Vbrj4KvVo5nvnScwsx25LK+tPE3AM/IMcHuDW5zzp4Kup9xKd5YXupRJHzw=="
	privkey := "7F22ZeY+mlHtALq3sXcjrLdcID7whhVIQ5zD4bl4raKdBTYVgAjfdbvdfB5lmQa4wVP1o4frD5tfUcKON4ueVA=="
	_ = pubkey
	_ = privkey
	_, nonce := GenerateKey(32)

	sMsg := SignedMessage{}
	sMsg.MessageInfo.PublicKey = pubkey
	sMsg.MessageInfo.TimeStamp = time.Now().Local()
	sMsg.MessageInfo.Verb = "get"
	sMsg.MessageInfo.Nonce = nonce
	sMsg.MessageInfo.Body = "Get item id 42"
	sMsg.SetHash(privkey)
	jsonmsg,_:=json.Marshal(sMsg)
	fmt.Println("Hashed: ", sMsg.Hash)

	fmt.Printf("SignedMessage: %v.\n", string(jsonmsg))

}

func GenerateKey(keylength int) ([]byte, string) {
	key := make([]byte, keylength)
	rand.Read(key)
	base64str := base64.StdEncoding.EncodeToString(key)
	return key, base64str
}