bcrypt

Documentation

Overview

Package bcrypt implements the bcrypt hashing algorithm for crypt(3).

Index

• Constants
• Variables
• func Check(hash, password string) error
• func Key(password, salt []byte, cost uint8, opts *CompatibilityOptions) ([]byte, error)
• func NewHash(password string, cost uint8) (string, error)
• type CompatibilityOptions
  • func Params(hash string) (salt []byte, cost uint8, opts *CompatibilityOptions, err error)
• type InvalidCostError
  • func (e InvalidCostError) Error() string
• type InvalidSaltError
  • func (e InvalidSaltError) Error() string
• type InvalidSaltLengthError
  • func (e InvalidSaltLengthError) Error() string
• type UnsupportedPrefixError
  • func (e UnsupportedPrefixError) Error() string

Examples

• Check
• Key
• Params

Constants

const (
	MinCost     = 4
	MaxCost     = 31
	DefaultCost = 12
)

const (
	Prefix2  = "$2$"  // the original bcrypt specification
	Prefix2a = "$2a$" // requires the string must be UTF-8 encoded and the null terminator must be included
	Prefix2b = "$2b$" // fixing bug with storing the string length in an unsigned char
)

const SaltLength = 22

Variables

var Encoding = base64.NewEncoding(encoder).WithPadding(base64.NoPadding)

Encoding is the unpadded base64 encoding, defined by a 64-character alphabet used by bcrypt.

Functions

func Check

func Check(hash, password string) error

Check compares the given crypt(3) bcrypt hash with a new hash derived from the password. Returns nil on success, or an error on failure.

Example

package main

import (
	"fmt"

	"github.com/sergeymakinen/go-crypt/bcrypt"
)

func main() {
	hash := "$2b$12$mBhJFLLDJCBCcmMN4DLyrOV.LLSl/mdwGfzwsqvIL0OQN5yXzRihO"
	fmt.Println(bcrypt.Check(hash, "password"))
	fmt.Println(bcrypt.Check(hash, "test"))
}

Output:

<nil>
hash and password mismatch

func Key

func Key(password, salt []byte, cost uint8, opts *CompatibilityOptions) ([]byte, error)

Key returns a bcrypt key derived from the password, salt, cost and compatibility options.

The opts parameter is optional. If nil, default options are used.

Example

package main

import (
	"fmt"

	"github.com/sergeymakinen/go-crypt/bcrypt"
)

func main() {
	salt, cost, opts, _ := bcrypt.Params("$2b$10$UVjcf7m8L91VOpIRwEprguF4o9Inqj7aNhqvSzUElX4GWGyIkYLuG")
	fmt.Println(string(salt))
	fmt.Println(cost)

	key, _ := bcrypt.Key([]byte("password"), salt, cost, opts)
	fmt.Println(bcrypt.Encoding.EncodeToString(key))
}

Output:

UVjcf7m8L91VOpIRwEprgu
10
F4o9Inqj7aNhqvSzUElX4GWGyIkYLuG

func NewHash

func NewHash(password string, cost uint8) (string, error)

NewHash returns the crypt(3) bcrypt hash of the password at the given cost.

Types

type CompatibilityOptions

type CompatibilityOptions struct {
	Prefix string
}

CompatibilityOptions are the key derivation parameters required to produce keys from old/non-standard hashes.

func Params

func Params(hash string) (salt []byte, cost uint8, opts *CompatibilityOptions, err error)

Params returns the hashing salt, cost, version and compatibility options used to create the given crypt(3) bcrypt hash.

Example

package main

import (
	"fmt"

	"github.com/sergeymakinen/go-crypt/bcrypt"
)

func main() {
	salt, cost, _, _ := bcrypt.Params("$2b$10$UVjcf7m8L91VOpIRwEprguF4o9Inqj7aNhqvSzUElX4GWGyIkYLuG")
	fmt.Println(string(salt))
	fmt.Println(cost)
}

Output:

UVjcf7m8L91VOpIRwEprgu
10

type InvalidCostError

type InvalidCostError uint8

InvalidCostError values describe errors resulting from an invalid cost.

func (InvalidCostError) Error

func (e InvalidCostError) Error() string

type InvalidSaltError

type InvalidSaltError byte

InvalidSaltError values describe errors resulting from an invalid character in a hash string.

func (InvalidSaltError) Error

func (e InvalidSaltError) Error() string

type InvalidSaltLengthError

type InvalidSaltLengthError int

InvalidSaltLengthError values describe errors resulting from an invalid length of a salt.

func (InvalidSaltLengthError) Error

func (e InvalidSaltLengthError) Error() string

type UnsupportedPrefixError

type UnsupportedPrefixError string

UnsupportedPrefixError values describe errors resulting from an unsupported prefix string.

func (UnsupportedPrefixError) Error

func (e UnsupportedPrefixError) Error() string