75 lines
1.8 KiB
Go
75 lines
1.8 KiB
Go
package crypto
|
|
|
|
import (
|
|
"crypto/aes"
|
|
"crypto/cipher"
|
|
"encoding/binary"
|
|
"errors"
|
|
|
|
"github.com/lucas-clemente/quic-go/internal/protocol"
|
|
)
|
|
|
|
type aeadAESGCM struct {
|
|
otherIV []byte
|
|
myIV []byte
|
|
encrypter cipher.AEAD
|
|
decrypter cipher.AEAD
|
|
}
|
|
|
|
var _ AEAD = &aeadAESGCM{}
|
|
|
|
const ivLen = 12
|
|
|
|
// NewAEADAESGCM creates a AEAD using AES-GCM
|
|
func NewAEADAESGCM(otherKey []byte, myKey []byte, otherIV []byte, myIV []byte) (AEAD, error) {
|
|
// the IVs need to be at least 8 bytes long, otherwise we can't compute the nonce
|
|
if len(otherIV) != ivLen || len(myIV) != ivLen {
|
|
return nil, errors.New("AES-GCM: expected 12 byte IVs")
|
|
}
|
|
|
|
encrypterCipher, err := aes.NewCipher(myKey)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
encrypter, err := cipher.NewGCM(encrypterCipher)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
decrypterCipher, err := aes.NewCipher(otherKey)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
decrypter, err := cipher.NewGCM(decrypterCipher)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return &aeadAESGCM{
|
|
otherIV: otherIV,
|
|
myIV: myIV,
|
|
encrypter: encrypter,
|
|
decrypter: decrypter,
|
|
}, nil
|
|
}
|
|
|
|
func (aead *aeadAESGCM) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, error) {
|
|
return aead.decrypter.Open(dst, aead.makeNonce(aead.otherIV, packetNumber), src, associatedData)
|
|
}
|
|
|
|
func (aead *aeadAESGCM) Seal(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) []byte {
|
|
return aead.encrypter.Seal(dst, aead.makeNonce(aead.myIV, packetNumber), src, associatedData)
|
|
}
|
|
|
|
func (aead *aeadAESGCM) makeNonce(iv []byte, packetNumber protocol.PacketNumber) []byte {
|
|
nonce := make([]byte, ivLen)
|
|
binary.BigEndian.PutUint64(nonce[ivLen-8:], uint64(packetNumber))
|
|
for i := 0; i < ivLen; i++ {
|
|
nonce[i] ^= iv[i]
|
|
}
|
|
return nonce
|
|
}
|
|
|
|
func (aead *aeadAESGCM) Overhead() int {
|
|
return aead.encrypter.Overhead()
|
|
}
|