2 GoVPN -- simple secure free software virtual private network daemon
3 Copyright (C) 2014-2016 Sergey Matveev <stargrave@stargrave.org>
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
24 "cypherpunks.ru/govpn/aont"
25 "cypherpunks.ru/govpn/cnw"
29 EnclessEnlargeSize = aont.HSize + aont.RSize*cnw.EnlargeFactor
32 // Confidentiality preserving (but encryptionless) encoding.
34 // It uses Chaffing-and-Winnowing technology (it is neither
35 // encryption nor steganography) over All-Or-Nothing-Transformed data.
36 // nonce is 64-bit nonce. Output data will be EnclessEnlargeSize larger.
37 // It also consumes 64-bits of entropy.
38 func EnclessEncode(authKey *[32]byte, nonce *[16]byte, in []byte) ([]byte, error) {
39 r := new([aont.RSize]byte)
41 if _, err = io.ReadFull(Rand, r[:]); err != nil {
44 aonted, err := aont.Encode(r, in)
49 cnw.Chaff(authKey, nonce[8:], aonted[:aont.RSize]),
50 aonted[aont.RSize:]...,
52 SliceZero(aonted[:aont.RSize])
56 // Decode EnclessEncode-ed data.
57 func EnclessDecode(authKey *[32]byte, nonce *[16]byte, in []byte) ([]byte, error) {
59 winnowed, err := cnw.Winnow(
60 authKey, nonce[8:], in[:aont.RSize*cnw.EnlargeFactor],
65 out, err := aont.Decode(append(
66 winnowed, in[aont.RSize*cnw.EnlargeFactor:]...,