golang v4 UUID generator

main.go

package main

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

func main() {
	id := make([]byte, 16)
	rand.Read(id)
	id[6] = (id[6] & 0x0f) | 0x40
	id[8] = (id[8] & 0x3f) | 0x80
	wall := []byte("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")
	hex.Encode(wall, id[:4])
	hex.Encode(wall[9:13], id[4:6])
	hex.Encode(wall[14:18], id[6:8])
	hex.Encode(wall[19:23], id[8:10])
	hex.Encode(wall[24:], id[10:])
	fmt.Println(string(wall))
}