pbkdf2

Documentation

Overview

Package pbkdf2 implements a password encoding mechanism for the mcf framework

Index

• Constants
• Variables
• func SetConfig(config Config) error
• type Config
  • func GetConfig() Config
  • func (c *Config) AtLeast(current_imp bridge.Implementer) bool
  • func (c *Config) Key(password, salt []byte) ([]byte, error)
  • func (c *Config) Params() string
  • func (c *Config) Salt() ([]byte, error)
  • func (c *Config) SetParams(params string) error
• type ErrInvalidHash
  • func (e *ErrInvalidHash) Error() string
• type Hash
  • func (h Hash) Size() int
  • func (h Hash) String() string

Constants

const (
	DefaultIterations = 2000

	DefaultSaltLen = 16

	DefaultPrf = SHA1
)

Default values. These are exported for documentation purposes. See GetConfig() and SetConfig() on how to change them.

Variables

var DefaultKeyLen = DefaultPrf.Size()

This value is exported for documentation purposes. See GetConfig() and SetConfig() on how to change it. Defined as a var to allow for non constant initialization.

var SaltMine mcf.SaltMiner = nil

SaltMine is a custom source of salt, which is normally unset. Change this to override the use of rand.Reader if you need to use a custom salt producer.

Functions

func SetConfig

func SetConfig(config Config) error

SetConfig establishes a new default configuration for this algorithm. It is only necessary to set the configuration if this algorithm is the default algorithm. To change a configuration, Get a copy of the configuration

config := pbkdf2.GetConfig()

Change as necessary

config.Iterations *= 1.5        // increase iterations by 50%
config.Hash = pbkdf2.SHA256  // change hmac
config.KeyLen= pbkdf2.SHA256.Size()

then set

err := pbkdf2.SetConfig(config)
// error handling elided

Types

type Config

type Config struct {
	// The Pseudo Random Function (prf) used by the PBKDF2 algorithm.
	// When this value is changed, KeyLen will most likely need to change as well
	// since hash functions generally produce output of differing lengths.
	Hash Hash

	// Number of iteration rounds in the PBKDF2 algorithm.
	// The RFC recommends at least 1000
	Iterations int

	// Length of key produced by algorithm in bytes.
	// Defaults to the output length of the HMAC Hash.
	KeyLen int

	// Size of salt in bytes.
	// The RFC recommends at least 8 bytes.
	SaltLen int
}

Config contains the parameters for the PBKDF2 algorithm along with associated values.

func GetConfig

func GetConfig() Config

Returns the default configuration. To change default values, pass the modified output of GetConfig() to SetConfig(). See SetConfig() for an example.

func (*Config) AtLeast

func (c *Config) AtLeast(current_imp bridge.Implementer) bool

AtLeast compares the parameters for an encoded password to the current configuration and returns true if the encoded password configuration has the same or longer configuration parameter values.

func (*Config) Key

func (c *Config) Key(password, salt []byte) ([]byte, error)

Key generates a PBKDF2 digest from the password, salt and iteration count, using the Hash as a pseudorandom function.

func (*Config) Params

func (c *Config) Params() string

Params encodes algorithm parameters in a string for later use.

func (*Config) Salt

func (c *Config) Salt() ([]byte, error)

Salt produces SaltLen bytes of random data.

func (*Config) SetParams

func (c *Config) SetParams(params string) error

SetParams extracts encoded algorithm parameters from the output of Params().

type ErrInvalidHash

type ErrInvalidHash struct {
	Hash Hash
}

ErrInvalidHash is returned when an invalid Hash is encountered. The name of the hash is printed in the Error() string and is also exported.

func (*ErrInvalidHash) Error

func (e *ErrInvalidHash) Error() string

ErrInvalidHash implements the Error interface.

type Hash

type Hash string

Hash represents the HMAC hash function that the PBKDF2 algorithm uses as a pseudorandom function.

const (
	SHA1   Hash = "SHA1"
	SHA224 Hash = "SHA224"
	SHA256 Hash = "SHA256"
	SHA384 Hash = "SHA384"
	SHA512 Hash = "SHA512"
)

Available hashes

func (Hash) Size

func (h Hash) Size() int

Size is the output length of the hash function.

func (Hash) String

func (h Hash) String() string

Hash implements the Stringer interface