Generate keys with crypto/rand

main.go

// Do not use package math/rand to generate keys, even throwaway ones. 
// Unseeded, the generator is completely predictable. Seeded with 
// time.Nanoseconds(), there are just a few bits of entropy. Instead, 
// use crypto/rand's Reader, and if you need text, print to hexadecimal 
// or base64.
package main

import (
	"crypto/rand"
	"fmt"
)

func main() {
	buf := make([]byte, 16)
	_, err := rand.Read(buf)
	if err != nil {
		panic(err) // out of randomness, should never happen
	}
	fmt.Printf("%x\n", buf)
	// or hex.EncodeToString(buf)
	// or base64.StdEncoding.EncodeToString(buf)
}