sc: stream cipher abstraction applied to arcfour
A minor bug was discovered in padding of short message signatures. If is silently fixed, causing some (very minor) incompatibility of signatures with previous versions.
This commit is contained in:
parent
8c1d39d0e0
commit
e687629323
|
|
@ -1,6 +1,9 @@
|
|||
|
||||
Codecrypt ChangeLog
|
||||
|
||||
- virtualize the stream ciphers
|
||||
- fix fmtseq short message padding bug (fixed by previous)
|
||||
|
||||
1.5
|
||||
|
||||
- add hashfile support with -S
|
||||
|
|
|
|||
|
|
@ -246,14 +246,13 @@ static bool message_unpad (std::vector<byte> in, bvector&out,
|
|||
* otherwise it probably fails. miserably.
|
||||
*/
|
||||
|
||||
#define arcfour_discard 4096
|
||||
|
||||
template < class pubkey_type,
|
||||
int plainsize,
|
||||
int ciphersize,
|
||||
int errorcount,
|
||||
class hash_type,
|
||||
class pad_hash_type,
|
||||
class scipher,
|
||||
int ranksize >
|
||||
static int fo_encrypt (const bvector&plain, bvector&cipher,
|
||||
sencode* pubkey, prng&rng)
|
||||
|
|
@ -304,17 +303,13 @@ static int fo_encrypt (const bvector&plain, bvector&cipher,
|
|||
if (Pub.encrypt (mce_plain, cipher, ev) ) return 5;
|
||||
|
||||
//encrypt the message part (xor with arcfour)
|
||||
arcfour<byte> arc;
|
||||
arc.init (8);
|
||||
scipher sc;
|
||||
sc.init ();
|
||||
//whole key must be tossed in, so split if when necessary
|
||||
for (i = 0; i < (K.size() >> 8); ++i) {
|
||||
std::vector<byte> subkey (K.begin() + (i << 8),
|
||||
MIN (K.end(),
|
||||
K.begin() + ( (i + 1) << 8) ) );
|
||||
arc.load_key (subkey);
|
||||
}
|
||||
arc.discard (arcfour_discard);
|
||||
for (i = 0; i < M.size(); ++i) M[i] = M[i] ^ arc.gen();
|
||||
sc.load_key (K);
|
||||
|
||||
//encrypt
|
||||
for (i = 0; i < M.size(); ++i) M[i] = M[i] ^ sc.gen();
|
||||
|
||||
//append the message part to the ciphertext
|
||||
cipher.resize (ciphersize + (M.size() << 3) );
|
||||
|
|
@ -330,6 +325,7 @@ template < class privkey_type,
|
|||
int errorcount,
|
||||
class hash_type,
|
||||
class pad_hash_type,
|
||||
class scipher,
|
||||
int ranksize >
|
||||
static int fo_decrypt (const bvector&cipher, bvector&plain,
|
||||
sencode* privkey)
|
||||
|
|
@ -370,18 +366,13 @@ static int fo_decrypt (const bvector&cipher, bvector&plain,
|
|||
if (cipher[ciphersize + i]) M[i >> 3] |= 1 << (i & 0x7);
|
||||
|
||||
//prepare arcfour
|
||||
arcfour<byte> arc;
|
||||
arc.init (8);
|
||||
scipher sc;
|
||||
sc.init ();
|
||||
//stuff in the whole key
|
||||
for (i = 0; i < (K.size() >> 8); ++i) {
|
||||
std::vector<byte> subkey (K.begin() + (i << 8),
|
||||
MIN (K.end(),
|
||||
K.begin() + ( (i + 1) << 8) ) );
|
||||
arc.load_key (subkey);
|
||||
}
|
||||
arc.discard (arcfour_discard);
|
||||
sc.load_key (K);
|
||||
|
||||
//decrypt the message part
|
||||
for (i = 0; i < M.size(); ++i) M[i] = M[i] ^ arc.gen();
|
||||
for (i = 0; i < M.size(); ++i) M[i] = M[i] ^ sc.gen();
|
||||
|
||||
//compute the hash of K+M
|
||||
std::vector<byte>H, M2;
|
||||
|
|
@ -413,6 +404,8 @@ static int fo_decrypt (const bvector&cipher, bvector&plain,
|
|||
* Instances for actual encryption/descryption algorithms
|
||||
*/
|
||||
|
||||
typedef arcfour<byte, 8, 4096> arcfour_fo_cipher;
|
||||
|
||||
#if HAVE_CRYPTOPP==1
|
||||
|
||||
#include "sha_hash.h"
|
||||
|
|
@ -426,6 +419,7 @@ int algo_mceqd128::encrypt (const bvector&plain, bvector&cipher,
|
|||
2048, 4096, 128,
|
||||
sha256hash,
|
||||
rmd128hash,
|
||||
arcfour_fo_cipher,
|
||||
816 >
|
||||
(plain, cipher, pubkey, rng);
|
||||
}
|
||||
|
|
@ -438,6 +432,7 @@ int algo_mceqd192::encrypt (const bvector&plain, bvector&cipher,
|
|||
2816, 6912, 256,
|
||||
sha384hash,
|
||||
rmd128hash,
|
||||
arcfour_fo_cipher,
|
||||
1574 >
|
||||
(plain, cipher, pubkey, rng);
|
||||
}
|
||||
|
|
@ -450,6 +445,7 @@ int algo_mceqd256::encrypt (const bvector&plain, bvector&cipher,
|
|||
4096, 8192, 256,
|
||||
sha512hash,
|
||||
rmd128hash,
|
||||
arcfour_fo_cipher,
|
||||
1638 >
|
||||
(plain, cipher, pubkey, rng);
|
||||
}
|
||||
|
|
@ -462,6 +458,7 @@ int algo_mceqd128::decrypt (const bvector&cipher, bvector&plain,
|
|||
2048, 4096, 128,
|
||||
sha256hash,
|
||||
rmd128hash,
|
||||
arcfour_fo_cipher,
|
||||
816 >
|
||||
(cipher, plain, privkey);
|
||||
}
|
||||
|
|
@ -474,6 +471,7 @@ int algo_mceqd192::decrypt (const bvector&cipher, bvector&plain,
|
|||
2816, 6912, 256,
|
||||
sha384hash,
|
||||
rmd128hash,
|
||||
arcfour_fo_cipher,
|
||||
1574 >
|
||||
(cipher, plain, privkey);
|
||||
}
|
||||
|
|
@ -486,6 +484,7 @@ int algo_mceqd256::decrypt (const bvector&cipher, bvector&plain,
|
|||
4096, 8192, 256,
|
||||
sha512hash,
|
||||
rmd128hash,
|
||||
arcfour_fo_cipher,
|
||||
1638 >
|
||||
(cipher, plain, privkey);
|
||||
}
|
||||
|
|
@ -502,6 +501,7 @@ int algo_mceqd128cube::encrypt (const bvector&plain, bvector&cipher,
|
|||
2048, 4096, 128,
|
||||
cube256hash,
|
||||
cube128hash,
|
||||
arcfour_fo_cipher,
|
||||
816 >
|
||||
(plain, cipher, pubkey, rng);
|
||||
}
|
||||
|
|
@ -514,6 +514,7 @@ int algo_mceqd192cube::encrypt (const bvector&plain, bvector&cipher,
|
|||
2816, 6912, 256,
|
||||
cube384hash,
|
||||
cube128hash,
|
||||
arcfour_fo_cipher,
|
||||
1574 >
|
||||
(plain, cipher, pubkey, rng);
|
||||
}
|
||||
|
|
@ -526,6 +527,7 @@ int algo_mceqd256cube::encrypt (const bvector&plain, bvector&cipher,
|
|||
4096, 8192, 256,
|
||||
cube512hash,
|
||||
cube128hash,
|
||||
arcfour_fo_cipher,
|
||||
1638 >
|
||||
(plain, cipher, pubkey, rng);
|
||||
}
|
||||
|
|
@ -538,6 +540,7 @@ int algo_mceqd128cube::decrypt (const bvector&cipher, bvector&plain,
|
|||
2048, 4096, 128,
|
||||
cube256hash,
|
||||
cube128hash,
|
||||
arcfour_fo_cipher,
|
||||
816 >
|
||||
(cipher, plain, privkey);
|
||||
}
|
||||
|
|
@ -550,6 +553,7 @@ int algo_mceqd192cube::decrypt (const bvector&cipher, bvector&plain,
|
|||
2816, 6912, 256,
|
||||
cube384hash,
|
||||
cube128hash,
|
||||
arcfour_fo_cipher,
|
||||
1574 >
|
||||
(cipher, plain, privkey);
|
||||
}
|
||||
|
|
@ -562,6 +566,7 @@ int algo_mceqd256cube::decrypt (const bvector&cipher, bvector&plain,
|
|||
4096, 8192, 256,
|
||||
cube512hash,
|
||||
cube128hash,
|
||||
arcfour_fo_cipher,
|
||||
1638 >
|
||||
(cipher, plain, privkey);
|
||||
}
|
||||
|
|
|
|||
|
|
@ -55,6 +55,8 @@
|
|||
|
||||
#define MIN(a,b) ((a)<(b)?(a):(b))
|
||||
|
||||
typedef arcfour<byte, 8, 256> padding_generator;
|
||||
|
||||
static void msg_pad (const bvector&in, std::vector<byte>&out, size_t minsize)
|
||||
{
|
||||
uint i;
|
||||
|
|
@ -66,17 +68,10 @@ static void msg_pad (const bvector&in, std::vector<byte>&out, size_t minsize)
|
|||
|
||||
if (out.size() >= minsize) return;
|
||||
|
||||
arcfour<byte> g;
|
||||
g.init (8);
|
||||
|
||||
padding_generator g;
|
||||
g.init ();
|
||||
//stuff in as much seed material as possible
|
||||
for (i = 0; i < (out.size() >> 8); ++i) {
|
||||
std::vector<byte> sub (out.begin() + (i << 8),
|
||||
MIN (out.end(),
|
||||
out.begin() + ( (i + 1) << 8) ) );
|
||||
g.load_key (sub);
|
||||
}
|
||||
g.discard (256);
|
||||
g.load_key (out);
|
||||
|
||||
i = out.size();
|
||||
out.resize (minsize);
|
||||
|
|
|
|||
|
|
@ -19,17 +19,18 @@
|
|||
#ifndef _ccr_rc4_h_
|
||||
#define _ccr_rc4_h_
|
||||
|
||||
#include "sc.h"
|
||||
|
||||
#include <vector>
|
||||
|
||||
#include <sys/types.h>
|
||||
|
||||
template<class inttype> class arcfour
|
||||
template<class inttype = byte, int bits = 8, int disc_bytes = 0>
|
||||
class arcfour : public streamcipher
|
||||
{
|
||||
std::vector<inttype> S;
|
||||
inttype I, J;
|
||||
inttype mask;
|
||||
public:
|
||||
bool init (unsigned bits) {
|
||||
bool init () {
|
||||
size_t Ssize = 1 << bits;
|
||||
if (bits > 8 * sizeof (inttype) ) return false;
|
||||
I = J = 0;
|
||||
|
|
@ -46,14 +47,30 @@ public:
|
|||
S.clear();
|
||||
}
|
||||
|
||||
void load_key (const std::vector<inttype>&K) {
|
||||
inttype j = 0, t;
|
||||
for (size_t i = 0; i <= mask; ++i) {
|
||||
j = (j + S[i] + K[i % K.size()]) & mask;
|
||||
t = S[j];
|
||||
S[j] = S[i];
|
||||
S[i] = t;
|
||||
void load_key (const inttype*begin, const inttype*end) {
|
||||
inttype j, t;
|
||||
size_t i;
|
||||
const inttype *keypos;
|
||||
|
||||
//eat whole key iteratively, even if longer than permutation
|
||||
for (; begin < end; begin += mask + 1) {
|
||||
j = 0;
|
||||
for (i = 0, keypos = begin;
|
||||
i <= mask;
|
||||
++i, ++keypos) {
|
||||
if (keypos >= end) keypos = begin; //rotate
|
||||
j = (j + S[i] + (*keypos) ) & mask;
|
||||
t = S[j];
|
||||
S[j] = S[i];
|
||||
S[i] = t;
|
||||
}
|
||||
}
|
||||
|
||||
discard (disc_bytes);
|
||||
}
|
||||
|
||||
void load_key (const std::vector<inttype>&K) {
|
||||
load_key (& (K[0]), & (K[K.size()]) );
|
||||
}
|
||||
|
||||
inttype gen() {
|
||||
|
|
@ -68,13 +85,20 @@ public:
|
|||
return S[ (S[I] + S[J]) & mask];
|
||||
}
|
||||
|
||||
void discard (size_t n) {
|
||||
for (size_t i = 0; i < n; ++i) gen();
|
||||
void gen (size_t n, inttype*out) {
|
||||
if (out)
|
||||
for (size_t i = 0; i < n; ++i) out[i] = gen();
|
||||
else
|
||||
for (size_t i = 0; i < n; ++i) gen();
|
||||
}
|
||||
|
||||
void gen (size_t n, std::vector<inttype>&out) {
|
||||
out.resize (n);
|
||||
for (size_t i = 0; i < n; ++i) out[i] = gen();
|
||||
gen (n, & (out[0]) );
|
||||
}
|
||||
|
||||
size_t block_size() {
|
||||
return 1;
|
||||
}
|
||||
};
|
||||
|
||||
|
|
|
|||
|
|
@ -21,10 +21,12 @@
|
|||
|
||||
using namespace fmtseq;
|
||||
|
||||
void prepare_keygen (arcfour<byte>& kg, const std::vector<byte>&SK, uint idx)
|
||||
typedef arcfour<byte, 8, 0> privgen;
|
||||
|
||||
void prepare_keygen (privgen& kg, const std::vector<byte>&SK, uint idx)
|
||||
{
|
||||
kg.clear();
|
||||
kg.init (8);
|
||||
kg.init ();
|
||||
kg.load_key (SK);
|
||||
std::vector<byte>tmp;
|
||||
while (idx) {
|
||||
|
|
@ -34,6 +36,8 @@ void prepare_keygen (arcfour<byte>& kg, const std::vector<byte>&SK, uint idx)
|
|||
tmp.resize (16, 0); //prevent chaining to other numbers
|
||||
kg.load_key (tmp);
|
||||
kg.discard (4096);
|
||||
//discarding is done manually here,
|
||||
//for the purpose of double key loading.
|
||||
}
|
||||
|
||||
static void add_zero_checksum (bvector& v)
|
||||
|
|
@ -135,7 +139,7 @@ static bool check_privkey (privkey&priv, hash_func&hf)
|
|||
static void update_privkey (privkey&priv, hash_func&hf)
|
||||
{
|
||||
uint i, j;
|
||||
arcfour<byte> generator;
|
||||
privgen generator;
|
||||
std::vector<byte> x, Y;
|
||||
uint commitments = fmtseq_commitments (priv.hs);
|
||||
|
||||
|
|
@ -289,7 +293,7 @@ int fmtseq::generate (pubkey&pub, privkey&priv,
|
|||
|
||||
uint commitments = fmtseq_commitments (hs);
|
||||
|
||||
arcfour<byte> generator;
|
||||
privgen generator;
|
||||
std::vector<byte> x, Y;
|
||||
|
||||
alloc_exist (priv);
|
||||
|
|
@ -384,7 +388,7 @@ int privkey::sign (const bvector& hash, bvector& sig, hash_func& hf)
|
|||
|
||||
Sig.reserve (hf.size() * (commitments + h * l) );
|
||||
//first, compute the commitments and push them to the signature
|
||||
arcfour<byte> generator;
|
||||
privgen generator;
|
||||
prepare_keygen (generator, SK, sigs_used);
|
||||
for (i = 0; i < commitments; ++i) {
|
||||
//generate x_i
|
||||
|
|
|
|||
|
|
@ -41,6 +41,5 @@ void arcfour_rng::seed (uint bits, bool quick)
|
|||
f.close();
|
||||
|
||||
r.load_key (s);
|
||||
r.discard (4096);
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -25,10 +25,10 @@
|
|||
class arcfour_rng : public prng
|
||||
{
|
||||
public:
|
||||
arcfour<byte> r;
|
||||
arcfour<byte, 8, 4096> r;
|
||||
|
||||
arcfour_rng() {
|
||||
r.init (8);
|
||||
r.init ();
|
||||
}
|
||||
|
||||
~arcfour_rng() {
|
||||
|
|
|
|||
41
src/sc.h
Normal file
41
src/sc.h
Normal file
|
|
@ -0,0 +1,41 @@
|
|||
|
||||
/*
|
||||
* This file is part of Codecrypt.
|
||||
*
|
||||
* Codecrypt is free software: you can redistribute it and/or modify it
|
||||
* under the terms of the GNU Lesser General Public License as published by
|
||||
* the Free Software Foundation, either version 3 of the License, or (at
|
||||
* your option) any later version.
|
||||
*
|
||||
* Codecrypt is distributed in the hope that it will be useful, but WITHOUT
|
||||
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||||
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
|
||||
* License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU Lesser General Public License
|
||||
* along with Codecrypt. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
|
||||
#ifndef _ccr_sc_h_
|
||||
#define _ccr_sc_h_
|
||||
|
||||
#include "types.h"
|
||||
|
||||
#include <sys/types.h>
|
||||
|
||||
class streamcipher
|
||||
{
|
||||
public:
|
||||
virtual bool init() = 0;
|
||||
virtual void clear() = 0;
|
||||
virtual void load_key (const byte*begin, const byte*end) = 0;
|
||||
virtual byte gen() = 0;
|
||||
virtual void gen (size_t n, byte*out) = 0;
|
||||
virtual size_t block_size() = 0;
|
||||
|
||||
void discard (size_t n) {
|
||||
gen (n, 0);
|
||||
}
|
||||
};
|
||||
|
||||
#endif
|
||||
Loading…
Reference in a new issue