```

package main

import (

"encoding/hex"

"fmt"

"math/rand"

"time"

)

func main() {

rand.Seed(time.Now().UnixNano())

uLen:=20

  b:= make([]byte, uLen)

rand.Read(b)

rand_str:= hex.EncodeToString(b)[0:uLen]

fmt.Println(rand_str)

}

```