matterbridge/vendor/go.mau.fi/whatsmeow/util/keys/keypair.go
2022-03-20 14:57:48 +01:00

76 lines
1.5 KiB
Go

// Copyright (c) 2021 Tulir Asokan
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
// Package keys contains a utility struct for elliptic curve keypairs.
package keys
import (
"crypto/rand"
"fmt"
"go.mau.fi/libsignal/ecc"
"golang.org/x/crypto/curve25519"
)
type KeyPair struct {
Pub *[32]byte
Priv *[32]byte
}
var _ ecc.ECPublicKeyable
func NewKeyPairFromPrivateKey(priv [32]byte) *KeyPair {
var kp KeyPair
kp.Priv = &priv
var pub [32]byte
curve25519.ScalarBaseMult(&pub, kp.Priv)
kp.Pub = &pub
return &kp
}
func NewKeyPair() *KeyPair {
var priv [32]byte
_, err := rand.Read(priv[:])
if err != nil {
panic(fmt.Errorf("failed to generate curve25519 private key: %w", err))
}
priv[0] &= 248
priv[31] &= 127
priv[31] |= 64
return NewKeyPairFromPrivateKey(priv)
}
func (kp *KeyPair) CreateSignedPreKey(keyID uint32) *PreKey {
newKey := NewPreKey(keyID)
newKey.Signature = kp.Sign(&newKey.KeyPair)
return newKey
}
func (kp *KeyPair) Sign(keyToSign *KeyPair) *[64]byte {
pubKeyForSignature := make([]byte, 33)
pubKeyForSignature[0] = ecc.DjbType
copy(pubKeyForSignature[1:], keyToSign.Pub[:])
signature := ecc.CalculateSignature(ecc.NewDjbECPrivateKey(*kp.Priv), pubKeyForSignature)
return &signature
}
type PreKey struct {
KeyPair
KeyID uint32
Signature *[64]byte
}
func NewPreKey(keyID uint32) *PreKey {
return &PreKey{
KeyPair: *NewKeyPair(),
KeyID: keyID,
}
}