Generate hmac256 from a string and present it in hex.

hmac256hex.go

package main

import (
	"crypto/hmac"
	"crypto/rand"
	"crypto/sha1"
	"encoding/hex"
	"fmt"
)

func GenerateSecret() string {
	b := make([]byte, 16)
	rand.Read(b)
	return fmt.Sprintf("%x", b)
}

func ComputeHmacHex(message, secret string) string {
	key := []byte(secret)
	h := hmac.New(sha1.New, key)
	h.Write([]byte(message))
	return hex.EncodeToString(h.Sum(nil))
}

func main() {
	secret := GenerateSecret()
	key := "system.load15"
	idx := ComputeHmacHex(key, secret)
	fmt.Println("secret:", secret)
	fmt.Println("key:", key)
	fmt.Println("idx:", idx)
}