netbird/signal/encryption.go
2021-05-15 15:20:49 +05:00

53 lines
1.8 KiB
Go

package signal
import (
"crypto/rand"
"fmt"
"golang.org/x/crypto/nacl/box"
"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
)
// As set of tools to encrypt/decrypt messages being sent through the Signal Exchange Service.
// We want to make sure that the Connection Candidates and other irrelevant (to the Signal Exchange)
// information can't be read anywhere else but the Peer the message is being sent to.
// These tools use Golang crypto package (Curve25519, XSalsa20 and Poly1305 to encrypt and authenticate)
// Wireguard keys are used for encryption
// Encrypt encrypts a message using local Wireguard private key and remote peer's public key.
func Encrypt(msg []byte, peersPublicKey wgtypes.Key, privateKey wgtypes.Key) ([]byte, error) {
nonce, err := genNonce()
if err != nil {
return nil, err
}
return box.Seal(nonce[:], msg, nonce, toByte32(peersPublicKey), toByte32(privateKey)), nil
}
// Decrypt decrypts a message that has been encrypted by the remote peer using Wireguard private key and remote peer's public key.
func Decrypt(encryptedMsg []byte, peersPublicKey wgtypes.Key, privateKey wgtypes.Key) ([]byte, error) {
nonce, err := genNonce()
if err != nil {
return nil, err
}
copy(nonce[:], encryptedMsg[:24])
opened, ok := box.Open(nil, encryptedMsg[24:], nonce, toByte32(peersPublicKey), toByte32(privateKey))
if !ok {
return nil, fmt.Errorf("failed to decrypt message from peer %s", peersPublicKey.String())
}
return opened, nil
}
// Generates nonce of size 24
func genNonce() (*[24]byte, error) {
var nonce [24]byte
if _, err := rand.Read(nonce[:]); err != nil {
return nil, err
}
return &nonce, nil
}
// Converts Wireguard key to byte array of size 32 (a format used by the golang crypto package)
func toByte32(key wgtypes.Key) *[32]byte {
return (*[32]byte)(&key)
}