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|
package scrypt
import (
"crypto/rand"
"encoding/hex"
"flag"
"fmt"
"io"
"os"
"slices"
gt "gotext"
g "gobang"
)
/*
#define _XOPEN_SOURCE 700
#include <stdlib.h>
#include <scrypt-kdf.h>
*/
import "C"
const (
MinimumPasswordLength = 16
_SALT_MIN_LENGTH = 32
_DESIRED_LENGTH = 32
_N = 1 << 15
r = 8
p = 1
)
var (
ErrSaltTooSmall = gt.Error(gt.Gettext("scrypt: salt is too small"))
ErrInternal = gt.Error(gt.Gettext("scrypt: internal error"))
)
type HashInputT struct{
Password []byte
Salt []byte
}
type CheckInputT struct{
Password []byte
Salt []byte
Hash []byte
}
type argsT struct{
allArgs []string
input HashInputT
}
type envT struct{
args argsT
in io.Reader
out io.Writer
err io.Writer
}
// Package scrypt implements the scrypt key derivation function as defined in
// Colin Percival's paper "Stronger Key Derivation via Sequential Memory-Hard
// Functions" (https://www.tarsnap.com/scrypt/scrypt.pdf).
//
//
// Key derives a key from the password, salt, and cost parameters, returning
// a byte slice of length keyLen that can be used as cryptographic key.
//
// N is a CPU/memory cost parameter, which must be a power of 2 greater than 1.
// r and p must satisfy r * p < 2³⁰. If the parameters do not satisfy the
// limits, the function returns a nil byte slice and an error.
//
// For example, you can get a derived key for e.g. AES-256 (which needs a
// 32-byte key) by doing:
//
// dk, err := scrypt.Key([]byte("some password"), salt, 32768, 8, 1, 32)
//
// The recommended parameters for interactive logins as of 2017 are N=32768, r=8
// and p=1. The parameters N, r, and p should be increased as memory latency and
// CPU parallelism increases; consider setting N to the highest power of 2 you
// can derive within 100 milliseconds. Remember to get a good random salt.
func scrypt(
password []byte,
salt []byte,
N int,
r int,
p int,
outlen int,
) ([]byte, error) {
passwordbuf := C.CBytes(password)
saltbuf := C.CBytes(salt)
defer C.free(passwordbuf)
defer C.free(saltbuf)
outbuf := C.malloc(C.size_t(outlen))
defer C.free(outbuf)
rv := C.scrypt_kdf(
(*C.uint8_t)(passwordbuf),
C.size_t(len(password)),
(*C.uint8_t)(saltbuf),
C.size_t(len(salt)),
C.uint64_t(N),
C.uint32_t(r),
C.uint32_t(p),
(*C.uint8_t)(outbuf),
C.size_t(outlen),
)
if rv != 0 {
return nil, ErrInternal
}
out := C.GoBytes(outbuf, C.int(outlen))
return out, nil
}
func Hash(input HashInputT) ([]byte, error) {
if len(input.Salt) < _SALT_MIN_LENGTH {
return nil, ErrSaltTooSmall
}
hash, err := scrypt(
input.Password,
input.Salt,
_N,
r,
p,
_DESIRED_LENGTH,
)
return hash, err
}
func SaltFrom(r io.Reader) ([]byte, error) {
buffer := make([]byte, _SALT_MIN_LENGTH)
_, err := io.ReadFull(r, buffer)
if err != nil {
return nil, err
}
return buffer, nil
}
func Salt() ([]byte, error) {
return SaltFrom(rand.Reader)
}
func Check(input CheckInputT) (bool, error) {
hashInput := HashInputT{
Password: input.Password,
Salt: input.Salt,
}
candidate, err := Hash(hashInput)
if err != nil {
return false, err
}
return slices.Equal(candidate, input.Hash), nil
}
func usage(argv0 string, w io.Writer) {
fmt.Fprintf(
w,
gt.Gettext("Usage: %s PASSWORD SALT\n"),
argv0,
)
}
func getopt(allArgs []string, w io.Writer) (argsT, int) {
argv0 := allArgs[0]
argv := allArgs[1:]
fs := flag.NewFlagSet("", flag.ContinueOnError)
fs.Usage = func() {}
fs.SetOutput(w)
if fs.Parse(argv) != nil {
usage(argv0, w)
return argsT{}, 2
}
subArgs := fs.Args()
if len(subArgs) != 2 {
usage(argv0, w)
return argsT{}, 2
}
password := []byte(subArgs[0])
salt := []byte(subArgs[1])
input := HashInputT{
Password: password,
Salt: salt,
}
return argsT{
allArgs: allArgs,
input: input,
}, 0
}
func run(env envT) int {
payload, err := Hash(env.args.input)
if err != nil {
fmt.Fprintln(env.err, err)
return 1
}
fmt.Fprintln(env.out, hex.EncodeToString(payload))
return 0
}
func Main() {
g.Init()
gt.Init(Name, LOCALEDIR)
args, rc := getopt(os.Args, os.Stderr)
g.ExitIf(rc)
os.Exit(run(envT{
args: args,
in: os.Stdin,
out: os.Stdout,
err: os.Stderr,
}))
}
|
