password.go

package utils

import (
	"bytes"
	"crypto/rand"
	"crypto/sha1"
	"github.com/iris-contrib/errors"
	"golang.org/x/crypto/scrypt"
	"io"
)

const SaltSize = 10
const secret = "8klGgUxAr0"

const cpuCost = 16384
const memCost = 8
const parallel = 1
const keyLen = 31

var (
	passDoNotMatch = errors.New("Wrong password")
)

func SaltedHash() ([]byte, error) {
	buf := make([]byte, SaltSize, SaltSize+sha1.Size)
	if _, err := io.ReadFull(rand.Reader, buf); err != nil {
		return nil, err
	}

	h := sha1.New()
	h.Write(buf)
	h.Write([]byte(secret))

	return h.Sum(buf), nil
}

func GenerateDigest(pass, salt []byte) (digest []byte, err error) {
	digest, err = scrypt.Key([]byte(pass), salt, cpuCost, memCost, parallel, keyLen)

	if err != nil {
		return nil, err
	}

	return digest, nil
}

func PassChecker(pass, digest, salt []byte) (err error) {
	var genDigest []byte

	genDigest, err = GenerateDigest(pass, salt)

	if err != nil {
		return err
	}

	if !bytes.Equal(digest, genDigest) {
		return passDoNotMatch
	}

	return nil
}