akovalenko/lnd.xprv
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

brontide: the encrypted packet length is no longer the associated data

Browse Source 
This commit modifies the current implementation to more closely match
what’s currently specified within the spec.

The encrypted+MAC’d packet length is no longer included as the
associated data for the encryption/decryption of transport messages.
This isn’t required as if an active attacker swaps out the encrypted
length in the byte string, the decryption+MAC check will simply fail as
the nonce won’t be in proper sequence.
This commit is contained in:
Olaoluwa Osuntokun 2016-11-14 15:10:48 -08:00
parent 6e01bb72b0
commit 75ea05aef6
No known key found for this signature in database
GPG Key ID: 9CC5B105D03521A2
1 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
brontide/noise.go
View File

@ -330,6 +330,8 @@ func NewBrontideMachine(initiator bool, localPub *btcec.PrivateKey,
return &BrontideMachine{handshakeState: handshake}
}
// TODO(roasbeef): add version bytes, paramterize in constructor above
const (
// ActOneSize is the size of the packet sent from initiator to
// responder in ActOne. The packet consists of an ephemeral key in
@ -613,10 +615,10 @@ func (b *BrontideMachine) WriteMessage(w io.Writer, p []byte) error {
return err
}
// Next, write out the encrypted packet itself. We use the encrypted
// packet length above as the AD to the cipher in order to bind both
// messages together thwarting an active attack.
cipherText := b.sendCipher.Encrypt(cipherLen, nil, p)
// Finally, write out the encrypted packet itself. We only write out a
// single packet, as any fragmentation should have taken place at a
// higher level.
cipherText := b.sendCipher.Encrypt(nil, nil, p)
if _, err := w.Write(cipherText); err != nil {
return err
}
@ -646,7 +648,5 @@ func (b *BrontideMachine) ReadMessage(r io.Reader) ([]byte, error) {
return nil, err
}
// Finally, return the decrypted packet ensuring that the encrypted
// packet length is authenticated along with the packet itself.
return b.recvCipher.Decrypt(cipherLen[:], nil, ciperText)
return b.recvCipher.Decrypt(nil, nil, ciperText)
}