Files
zeromesh/internal/vl1/noise.go

104 lines
2.2 KiB
Go

package vl1
import (
"crypto/cipher"
"crypto/rand"
"encoding/binary"
"fmt"
"io"
"golang.org/x/crypto/chacha20poly1305"
"golang.org/x/crypto/sha3"
)
type NoiseCipher struct {
sendCipher cipher.AEAD
recvCipher cipher.AEAD
sendNonce uint64
recvNonce uint64
}
func NewNoiseCipher(sendKey, recvKey [32]byte) *NoiseCipher {
send, err := chacha20poly1305.New(sendKey[:])
if err != nil {
panic(err)
}
recv, err := chacha20poly1305.New(recvKey[:])
if err != nil {
panic(err)
}
return &NoiseCipher{
sendCipher: send,
recvCipher: recv,
}
}
func DeriveKeysFromPSK(psk string, localPub, remotePub []byte) ([32]byte, [32]byte) {
h := sha3.New256()
h.Write([]byte(psk))
h.Write(localPub)
h.Write(remotePub)
sum := h.Sum(nil)
var sendKey, recvKey [32]byte
copy(sendKey[:], sum[:32])
h.Reset()
h.Write(sum)
h.Write([]byte("reverse"))
rev := h.Sum(nil)
copy(recvKey[:], rev[:32])
return sendKey, recvKey
}
func (nc *NoiseCipher) Encrypt(plaintext []byte) ([]byte, error) {
nonce := make([]byte, 12)
binary.BigEndian.PutUint64(nonce[4:], nc.sendNonce)
nc.sendNonce++
ciphertext := nc.sendCipher.Seal(nil, nonce, plaintext, nil)
return ciphertext, nil
}
func (nc *NoiseCipher) Decrypt(ciphertext []byte) ([]byte, error) {
nonce := make([]byte, 12)
binary.BigEndian.PutUint64(nonce[4:], nc.recvNonce)
nc.recvNonce++
plaintext, err := nc.recvCipher.Open(nil, nonce, ciphertext, nil)
if err != nil {
return nil, fmt.Errorf("decrypt: %w", err)
}
return plaintext, nil
}
func (nc *NoiseCipher) EncryptTo(buf []byte, plaintext []byte) (int, error) {
nonce := make([]byte, 12)
binary.BigEndian.PutUint64(nonce[4:], nc.sendNonce)
nc.sendNonce++
ciphertext := nc.sendCipher.Seal(buf[:0], nonce, plaintext, nil)
return len(ciphertext), nil
}
func (nc *NoiseCipher) DecryptTo(buf []byte, ciphertext []byte) ([]byte, error) {
nonce := make([]byte, 12)
binary.BigEndian.PutUint64(nonce[4:], nc.recvNonce)
nc.recvNonce++
plaintext, err := nc.recvCipher.Open(buf[:0], nonce, ciphertext, nil)
if err != nil {
return nil, fmt.Errorf("decrypt: %w", err)
}
return plaintext, nil
}
func generateSessionKey() [32]byte {
var key [32]byte
if _, err := io.ReadFull(rand.Reader, key[:]); err != nil {
panic(err)
}
return key
}