scrypth64

README

scrypt-h64 for Go

package scrypth64 // import "github.com/mjolnir42/scrypth64"

scrypth64 derives password hashes and verifies passwords against them
according to the scrypt-h64 specification. It includes a number of ready to
use parameter sets. The modular crypt format is used, and its de-facto
standard as well as historic precedents are followed.

func Digest(password string, params *Parameter) (Mcf, error)
func Verify(password string, mcf Mcf) (bool, error)
type Parameter struct { ... }
func DefaultParams() *Parameter
func HighParams() *Parameter
func PaperParams() *Parameter
type Mcf string
func (m Mcf) FromString(s string) (res Mcf, err error)

func Digest(password string, params *Parameter) (Mcf, error)
    Digest calculates a new scrypt digest and returns it as a scrypt-h64 MCF
    formatted string. If params is nil, DefaultParams are used. Returns an empty
    string if err != nil.

func Verify(password string, mcf Mcf) (bool, error)
    Verify takes a password and a scrypt-h64 string in MCF format and returns
    true is the password matches the provided digest. The result is always false
    if error != nil.

func (m Mcf) FromString(s string) (res Mcf, err error)
    FromString takes a string, validates it and returns it as a custom typed Mcf
    string.

Specification

See separate file Specification.md

Documentation

Overview

scrypth64 derives password hashes and verifies passwords against them according to the scrypt-h64 specification. It includes a number of ready to use parameter sets. The modular crypt format is used, and its de-facto standard as well as historic precedents are followed.

Index

• func Verify(password string, mcf Mcf) (bool, error)
• type Mcf
  • func Digest(password string, params *Parameter) (Mcf, error)
  • func FromString(s string) (res Mcf, err error)
  • func (m Mcf) String() string
• type Parameter
  • func DefaultParams() *Parameter
  • func HighParams() *Parameter
  • func PaperParams() *Parameter

Functions

func Verify

func Verify(password string, mcf Mcf) (bool, error)

Verify takes a password and a scrypt-h64 string in MCF format and returns true if the password matches the provided digest. The result is always false if error != nil.

Types

type Mcf

type Mcf string

Mcf is a custom string type to indicate that the underlying string is subject to specific formatting rules

func Digest

func Digest(password string, params *Parameter) (Mcf, error)

Digest calculates a new scrypt digest and returns it as a scrypt-h64 MCF formatted string. If params is nil, DefaultParams are used. Returns an empty string if err != nil.

func FromString

func FromString(s string) (res Mcf, err error)

FromString takes a string, validates it and returns it as a custom typed Mcf string.

func (Mcf) String

func (m Mcf) String() string

type Parameter

type Parameter struct {
	Iterations      uint16 // log2 of the iteration count
	BlockSizeFactor uint8  // scrypt r parameter
	Parallelism     uint8  // scrypt p parameter
	Length          uint16 // output length in bytes, dkLen parameter
	SaltLength      uint16 // salt length in bytes
}

Parameter contains all required parameters for scrypth64

func DefaultParams

func DefaultParams() *Parameter

DefaultParams returns a prefilled *Parameter with default values. The defaults represent a 64MiByte memory consumption by scrypt per calculation and are intended for 2016 high performance datacenter equipment, not mobile gadgets. Uses a 512bit salt and 384bit digest.

func HighParams

func HighParams() *Parameter

HighParams returns a prefilled *Parameter with the recommended high security parameters from the scrypt paper. These represent 1GiByte of used memory per scrypt calculation.

func PaperParams

func PaperParams() *Parameter

PaperParams returns a prefilled *Parameter with the recommended values from the scrypt paper. These represent 16MiByte of used memory per scrypt calculation. Additional values are chosen with popular values.