ratchet

Documentation

Overview

Package ratchet implements the axolotl ratchet, by Trevor Perrin. See https://github.com/trevp/axolotl/wiki.

Index

• type KeyExchange
• type Ratchet
  • func New(rand io.Reader) *Ratchet
  • func (r *Ratchet) CompleteKeyExchange(kx *KeyExchange, alice bool) error
  • func (r *Ratchet) Decrypt(ciphertext []byte) ([]byte, error)
  • func (r *Ratchet) Encrypt(out, msg []byte) []byte
  • func (r *Ratchet) FillKeyExchange(kx *KeyExchange) error
  • func (r *Ratchet) Marshal(now time.Time, lifetime time.Duration) *disk.RatchetState
  • func (r *Ratchet) Unmarshal(s *disk.RatchetState) error

Types

type KeyExchange

type KeyExchange struct {
	Cipher [sntrup4591761.CiphertextSize]byte
	Public []byte
}

type Ratchet

type Ratchet struct {
	MyPrivateKey        *[sntrup4591761.PrivateKeySize]byte
	MySigningPublic     *[ed25519.PublicKeySize]byte
	TheirIdentityPublic *[sha256.Size]byte
	TheirSigningPublic  *[ed25519.PublicKeySize]byte
	TheirPublicKey      *[sntrup4591761.PublicKeySize]byte

	// Now is an optional function that will be used to get the current
	// time. If nil, time.Now is used.
	Now func() time.Time

	MyHalf    *[32]byte
	TheirHalf *[32]byte
	// contains filtered or unexported fields
}

Ratchet contains the per-contact, crypto state.

func New

func New(rand io.Reader) *Ratchet

func (*Ratchet) CompleteKeyExchange

func (r *Ratchet) CompleteKeyExchange(kx *KeyExchange, alice bool) error

CompleteKeyExchange takes a KeyExchange message from the other party and establishes the ratchet.

func (*Ratchet) Decrypt

func (r *Ratchet) Decrypt(ciphertext []byte) ([]byte, error)

func (*Ratchet) Encrypt

func (r *Ratchet) Encrypt(out, msg []byte) []byte

Encrypt acts like append() but appends an encrypted version of msg to out.

func (*Ratchet) FillKeyExchange

func (r *Ratchet) FillKeyExchange(kx *KeyExchange) error

FillKeyExchange sets elements of kx with key exchange information from the ratchet.

func (*Ratchet) Marshal

func (r *Ratchet) Marshal(now time.Time, lifetime time.Duration) *disk.RatchetState

func (*Ratchet) Unmarshal

func (r *Ratchet) Unmarshal(s *disk.RatchetState) error