package main

import (
	"crypto/rand"
	"crypto/sha512"
	"encoding/hex"
	"flag"
	"fmt"
	"io"

	"go.cypherpunks.ru/balloon"
)

func main() {
	s := flag.Int("s", 1<<18, "Space cost, number of hash-sized blocks")
	t := flag.Int("t", 2, "Time cost, rounds")
	p := flag.Int("p", 4, "Number of threads")
	saltHex := flag.String("salt", "", "Salt, hexadecimal, optional")
	passwd := flag.String("passwd", "", "Password")
	flag.Parse()
	var salt []byte
	var err error
	if len(*saltHex) == 0 {
		salt = make([]byte, 8)
		_, err = io.ReadFull(rand.Reader, salt)
	} else {
		salt, err = hex.DecodeString(*saltHex)
	}
	if err != nil {
		panic(err)
	}
	fmt.Println(hex.EncodeToString(balloon.H(sha512.New, []byte(*passwd), salt, *s, *t, *p)))
}