forked from quic-go/quic-go
86b4ffdaaf
Unfortunately QUIC uses non-standard tag sizes with both AES-GCM and Poly1305. Adopting AES-GCM seems much harder, so I changed it to Chacha20Poly1305 and only made some slight changes to an existing algo. This should probably be double-checked at some point.
66 lines
1.9 KiB
Go
66 lines
1.9 KiB
Go
package crypto
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/cipher"
|
|
"encoding/binary"
|
|
"errors"
|
|
"io"
|
|
"io/ioutil"
|
|
|
|
"github.com/lucas-clemente/quic-go/crypto/chacha20poly1305trunc12"
|
|
"github.com/lucas-clemente/quic-go/protocol"
|
|
)
|
|
|
|
type aeadChacha20Poly1305 struct {
|
|
otherIV []byte
|
|
myIV []byte
|
|
encrypter cipher.AEAD
|
|
decrypter cipher.AEAD
|
|
}
|
|
|
|
// NewAEADChacha20Poly1305 creates a AEAD using chacha20poly1305
|
|
func NewAEADChacha20Poly1305(otherKey []byte, myKey []byte, otherIV []byte, myIV []byte) (AEAD, error) {
|
|
if len(myKey) != 32 || len(otherKey) != 32 || len(myIV) != 4 || len(otherIV) != 4 {
|
|
return nil, errors.New("chacha20poly1305: expected 32-byte keys and 4-byte IVs")
|
|
}
|
|
encrypter, err := chacha20poly1305trunc12.NewAEAD(myKey)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
decrypter, err := chacha20poly1305trunc12.NewAEAD(otherKey)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return &aeadChacha20Poly1305{
|
|
otherIV: otherIV,
|
|
myIV: myIV,
|
|
encrypter: encrypter,
|
|
decrypter: decrypter,
|
|
}, nil
|
|
}
|
|
|
|
func (aead *aeadChacha20Poly1305) Open(packetNumber protocol.PacketNumber, associatedData []byte, r io.Reader) (*bytes.Reader, error) {
|
|
ciphertext, err := ioutil.ReadAll(r)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
plaintext, err := aead.decrypter.Open(make([]byte, len(ciphertext)), makeNonce(aead.otherIV, packetNumber), ciphertext, associatedData)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return bytes.NewReader(plaintext), nil
|
|
}
|
|
|
|
func (aead *aeadChacha20Poly1305) Seal(packetNumber protocol.PacketNumber, b *bytes.Buffer, associatedData []byte, plaintext []byte) {
|
|
ciphertext := aead.encrypter.Seal(make([]byte, len(plaintext)+12), makeNonce(aead.myIV, packetNumber), plaintext, associatedData)
|
|
b.Write(ciphertext)
|
|
}
|
|
|
|
func makeNonce(iv []byte, packetNumber protocol.PacketNumber) []byte {
|
|
res := make([]byte, 12)
|
|
copy(res[0:4], iv)
|
|
binary.LittleEndian.PutUint64(res[4:12], uint64(packetNumber))
|
|
return res
|
|
}
|