golang demo.go

package main

import (
	"bytes"
	"crypto/sha256"
	"fmt"
	"math"
	"time"
)

func main() {

	//time differnece
	timeNow := time.Now()
	timeLater := timeNow.Add(time.Second * 16 * 60)

	delta := math.Ceil(timeLater.Sub(time.Now()).Minutes() / 5)
	fmt.Printf("------->%v\n", delta)

	// hash
	str := timeNow.String()
	fmt.Printf("----->%v\n", timeNow.UTC())
	sum := sha256.Sum256([]byte(str))
	fmt.Printf("%x", sum)

	// combine keys
	var keyBuffer bytes.Buffer
	key1 := []byte("hello")
	key2 := []byte("+word")
	key3 := []byte("+word1")
	key4 := []byte("+word2")
	keyBuffer.Write(key1)
	keyBuffer.Write(key2)
	keyBuffer.Write(key3)
	keyBuffer.Write(key4)
	combinedKey := keyBuffer.Bytes()
	fmt.Printf("------>%v\n", string(combinedKey))

}