ergo/irc/password_new.go

63 lines
2.0 KiB
Go

// Copyright (c) 2016- Daniel Oaks <daniel@danieloaks.net>
// released under the MIT license
package irc
import (
"crypto/rand"
"golang.org/x/crypto/bcrypt"
)
const newSaltLen = 30
const defaultPasswordCost = 14
// NewSalt returns a salt for crypto uses.
func NewSalt() ([]byte, error) {
salt := make([]byte, newSaltLen)
_, err := rand.Read(salt)
if err != nil {
var emptySalt []byte
return emptySalt, err
}
return salt, nil
}
// PasswordManager supports the hashing and comparing of passwords with the given salt.
type PasswordManager struct {
salt []byte
}
// NewPasswordManager returns a new PasswordManager with the given salt.
func NewPasswordManager(salt []byte) PasswordManager {
var pwm PasswordManager
pwm.salt = salt
return pwm
}
// assemblePassword returns an assembled slice of bytes for the given password details.
func (pwm *PasswordManager) assemblePassword(specialSalt []byte, password string) []byte {
var assembledPasswordBytes []byte
assembledPasswordBytes = append(assembledPasswordBytes, pwm.salt...)
assembledPasswordBytes = append(assembledPasswordBytes, '-')
assembledPasswordBytes = append(assembledPasswordBytes, specialSalt...)
assembledPasswordBytes = append(assembledPasswordBytes, '-')
assembledPasswordBytes = append(assembledPasswordBytes, []byte(password)...)
return assembledPasswordBytes
}
// GenerateFromPassword encrypts the given password.
func (pwm *PasswordManager) GenerateFromPassword(specialSalt []byte, password string) ([]byte, error) {
assembledPasswordBytes := pwm.assemblePassword(specialSalt, password)
return bcrypt.GenerateFromPassword(assembledPasswordBytes, defaultPasswordCost)
}
// CompareHashAndPassword compares a hashed password with its possible plaintext equivalent.
// Returns nil on success, or an error on failure.
func (pwm *PasswordManager) CompareHashAndPassword(hashedPassword []byte, specialSalt []byte, password string) error {
assembledPasswordBytes := pwm.assemblePassword(specialSalt, password)
return bcrypt.CompareHashAndPassword(hashedPassword, assembledPasswordBytes)
}