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algos_enc: fixup the padding for non-byte-aligned keys

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This commit is contained in:
Mirek Kratochvil 2015-11-15 20:32:44 +01:00
parent 78a00ae3ce
commit de4ee8aa39
4 changed files with 10 additions and 6 deletions
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12
src/algos_enc.cpp
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@ -259,6 +259,10 @@ static int fo_encrypt (const bvector&plain, bvector&cipher,
std::vector<byte> K; std::vector<byte> K;
K.resize (plainsize >> 3); K.resize (plainsize >> 3);
for (i = 0; i < K.size(); ++i) K[i] = rng.random (256); for (i = 0; i < K.size(); ++i) K[i] = rng.random (256);
if (plainsize & 7) { //the byte overlap
K.resize (1 + (plainsize >> 3), 0);
K[plainsize >> 3] = rng.random (256) % (1 << (uint) (plainsize & 7));
}
//create the base for error vector //create the base for error vector
std::vector<byte> H, M2; std::vector<byte> H, M2;
@ -269,7 +273,7 @@ static int fo_encrypt (const bvector&plain, bvector&cipher,
//prepare the error vector (rotate the hash so we don't need ultralong hash functions) //prepare the error vector (rotate the hash so we don't need ultralong hash functions)
bvector ev_rank; bvector ev_rank;
ev_rank.resize (ranksize); ev_rank.resize (ranksize, 0);
for (i = 0; i < ranksize; ++i) for (i = 0; i < ranksize; ++i)
ev_rank[i] = 1 & (H[ (i >> 3) % H.size()] >> (i & 0x7)); ev_rank[i] = 1 & (H[ (i >> 3) % H.size()] >> (i & 0x7));
@ -279,7 +283,7 @@ static int fo_encrypt (const bvector&plain, bvector&cipher,
//prepare plaintext //prepare plaintext
bvector mce_plain; bvector mce_plain;
mce_plain.from_bytes (K); mce_plain.from_bytes (K);
mce_plain.resize (plainsize, 0); //pad with 0's to exact size mce_plain.resize (plainsize, 0); //fit to exact size (there shouldn't be overflow)
//run McEliece //run McEliece
if (Pub.encrypt (mce_plain, cipher, ev)) return 5; if (Pub.encrypt (mce_plain, cipher, ev)) return 5;
@ -372,9 +376,7 @@ static int fo_decrypt (const bvector&cipher, bvector&plain,
//convert stuff to byte vectors //convert stuff to byte vectors
std::vector<byte> K, M; std::vector<byte> K, M;
bvector Kb; mce_plain.to_bytes (K);
mce_plain.get_block (0, plainsize, Kb);
Kb.to_bytes (K);
bvector Mb; bvector Mb;
cipher.get_block (ciphersize, msize, Mb); cipher.get_block (ciphersize, msize, Mb);

1
src/iohelpers.h
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@ -33,6 +33,7 @@
#define out_bin(x) std::cout << x #define out_bin(x) std::cout << x
#define outeol std::cout << std::endl #define outeol std::cout << std::endl
#define err(x) std::cerr << x << std::endl #define err(x) std::cerr << x << std::endl
#define err_bin(x) std::cerr << x
#define erreol std::cerr << std::endl #define erreol std::cerr << std::endl
#define progerr(x) std::cerr << argv[0] << ": " << x << std::endl #define progerr(x) std::cerr << argv[0] << ": " << x << std::endl

1
src/main.cpp
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@ -92,6 +92,7 @@ void test()
/* /*
* Dear hacker, * Dear hacker,
* use this function for quicktesting your stuff. * use this function for quicktesting your stuff.
* It gets executed by the -T parameter.
* Other places suck for that purpose. * Other places suck for that purpose.
*/ */
} }

2
src/mce_qcmdpc.cpp
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@ -258,7 +258,7 @@ int privkey::decrypt (const bvector & in_orig, bvector & out, bvector & errors)
for (i = 0; i < cs; ++i) for (i = 0; i < cs; ++i)
if (unsat[i] > max_unsat) max_unsat = unsat[i]; if (unsat[i] > max_unsat) max_unsat = unsat[i];
if (!max_unsat) break; if (!max_unsat) break;
if(max_unsat>bs) out("EROR?!!!"); if (max_unsat > bs) err ("mce_qcmdpc: weird decryption error, expect failures");
//TODO do something about possible timing attacks //TODO do something about possible timing attacks
uint threshold = 0; uint threshold = 0;