internal static void get_seed(HashFunctions hs, byte[] seed, int seedOff, byte[] sk, Tree.leafaddr a)
{
byte[] buffer = new byte[SPHINCS256Config.SEED_BYTES + 8];
ulong t;
int i;
for (i = 0; i < SPHINCS256Config.SEED_BYTES; i++)
{
buffer[i] = sk[i];
}
//4 bits to encode level
t = (uint)a.level;
//55 bits to encode subtree
t |= a.subtree << 4;
//5 bits to encode leaf
t |= a.subleaf << 59;
Pack.UInt64_To_LE(t, buffer, SPHINCS256Config.SEED_BYTES);
hs.varlen_hash(seed, seedOff, buffer, buffer.Length);
}
internal static void l_tree(HashFunctions hs, byte[] leaf, int leafOff, byte[] wots_pk, int pkOff, byte[] masks, int masksOff)
{
uint l = (uint)Wots.WOTS_L;
int i, j = 0;
for (i = 0; i < Wots.WOTS_LOG_L; i++)
{
for (j = 0; j < (l >> 1); j++)
{
hs.hash_2n_n_mask(wots_pk, pkOff + j * SPHINCS256Config.HASH_BYTES, wots_pk, pkOff + j * 2 * SPHINCS256Config.HASH_BYTES, masks, masksOff + i * 2 * SPHINCS256Config.HASH_BYTES);
}
if ((l & 1) != 0)
{
Array.Copy(wots_pk, pkOff + (l - 1) * SPHINCS256Config.HASH_BYTES, wots_pk, pkOff + (l >> 1) * SPHINCS256Config.HASH_BYTES, SPHINCS256Config.HASH_BYTES);
l = (l >> 1) + 1;
}
else
{
l = (l >> 1);
}
}
Array.Copy(wots_pk, pkOff, leaf, leafOff, SPHINCS256Config.HASH_BYTES);
}
bool verify(HashFunctions hs, byte[] m, byte[] sm, byte[] pk)
{
int i;
int smlen = sm.Length;
long leafidx = 0;
byte[] wots_pk = new byte[Wots.WOTS_L * SPHINCS256Config.HASH_BYTES];
byte[] pkhash = new byte[SPHINCS256Config.HASH_BYTES];
byte[] root = new byte[SPHINCS256Config.HASH_BYTES];
byte[] sig = new byte[CRYPTO_BYTES];
int sigp;
byte[] tpk = new byte[SPHINCS256Config.CRYPTO_PUBLICKEYBYTES];
if (smlen != CRYPTO_BYTES)
{
throw new ArgumentException("signature wrong size");
}
byte[] m_h = new byte[SPHINCS256Config.MSGHASH_BYTES];
for (i = 0; i < SPHINCS256Config.CRYPTO_PUBLICKEYBYTES; i++)
{
tpk[i] = pk[i];
}
// construct message hash
{
byte[] R = new byte[SPHINCS256Config.MESSAGE_HASH_SEED_BYTES];
for (i = 0; i < SPHINCS256Config.MESSAGE_HASH_SEED_BYTES; i++)
{
R[i] = sm[i];
}
Array.Copy(sm, 0, sig, 0, CRYPTO_BYTES);
IDigest mHash = hs.getMessageHash();
// input R
mHash.BlockUpdate(R, 0, SPHINCS256Config.MESSAGE_HASH_SEED_BYTES);
// input pub key
mHash.BlockUpdate(tpk, 0, SPHINCS256Config.CRYPTO_PUBLICKEYBYTES);
// input message
mHash.BlockUpdate(m, 0, m.Length);
mHash.DoFinal(m_h, 0);
}
sigp = 0;
sigp += SPHINCS256Config.MESSAGE_HASH_SEED_BYTES;
smlen -= SPHINCS256Config.MESSAGE_HASH_SEED_BYTES;
for (i = 0; i < (SPHINCS256Config.TOTALTREE_HEIGHT + 7) / 8; i++)
{
leafidx ^= ((long)(sig[sigp + i] & 0xff) << (8 * i));
}
Horst.horst_verify(hs, root, sig, sigp + (SPHINCS256Config.TOTALTREE_HEIGHT + 7) / 8,
tpk, m_h);
sigp += (SPHINCS256Config.TOTALTREE_HEIGHT + 7) / 8;
smlen -= (SPHINCS256Config.TOTALTREE_HEIGHT + 7) / 8;
sigp += Horst.HORST_SIGBYTES;
smlen -= Horst.HORST_SIGBYTES;
Wots w = new Wots();
for (i = 0; i < SPHINCS256Config.N_LEVELS; i++)
{
w.wots_verify(hs, wots_pk, sig, sigp, root, tpk);
sigp += Wots.WOTS_SIGBYTES;
smlen -= Wots.WOTS_SIGBYTES;
Tree.l_tree(hs, pkhash, 0, wots_pk, 0, tpk, 0);
validate_authpath(hs, root, pkhash, (uint)(leafidx & 0x1f), sig, sigp, tpk, SPHINCS256Config.SUBTREE_HEIGHT);
leafidx >>= 5;
sigp += SPHINCS256Config.SUBTREE_HEIGHT * SPHINCS256Config.HASH_BYTES;
smlen -= SPHINCS256Config.SUBTREE_HEIGHT * SPHINCS256Config.HASH_BYTES;
}
bool verified = true;
for (i = 0; i < SPHINCS256Config.HASH_BYTES; i++)
{
if (root[i] != tpk[i + Horst.N_MASKS * SPHINCS256Config.HASH_BYTES])
{
verified = false;
}
}
return(verified);
}
byte[] crypto_sign(HashFunctions hs, byte[] m, byte[] sk)
{
byte[] sm = new byte[CRYPTO_BYTES];
int i;
ulong leafidx;
byte[] R = new byte[SPHINCS256Config.MESSAGE_HASH_SEED_BYTES];
byte[] m_h = new byte[SPHINCS256Config.MSGHASH_BYTES];
ulong[] rnd = new ulong[8];
byte[] root = new byte[SPHINCS256Config.HASH_BYTES];
byte[] seed = new byte[SPHINCS256Config.SEED_BYTES];
byte[] masks = new byte[Horst.N_MASKS * SPHINCS256Config.HASH_BYTES];
int pk;
byte[] tsk = new byte[SPHINCS256Config.CRYPTO_SECRETKEYBYTES];
for (i = 0; i < SPHINCS256Config.CRYPTO_SECRETKEYBYTES; i++)
{
tsk[i] = sk[i];
}
// create leafidx deterministically
{
// shift scratch upwards so we can reuse msg later
int scratch = CRYPTO_BYTES - SPHINCS256Config.SK_RAND_SEED_BYTES;
// Copy secret random seed to scratch
Array.Copy(tsk, SPHINCS256Config.CRYPTO_SECRETKEYBYTES - SPHINCS256Config.SK_RAND_SEED_BYTES, sm, scratch, SPHINCS256Config.SK_RAND_SEED_BYTES);
IDigest d = hs.getMessageHash();
byte[] bRnd = new byte[d.GetDigestSize()];
d.BlockUpdate(sm, scratch, SPHINCS256Config.SK_RAND_SEED_BYTES);
d.BlockUpdate(m, 0, m.Length);
d.DoFinal(bRnd, 0);
// wipe sk
zerobytes(sm, scratch, SPHINCS256Config.SK_RAND_SEED_BYTES);
for (int j = 0; j != rnd.Length; j++)
{
rnd[j] = Pack.LE_To_UInt64(bRnd, j * 8);
}
leafidx = rnd[0] & 0xfffffffffffffffUL;
Array.Copy(bRnd, 16, R, 0, SPHINCS256Config.MESSAGE_HASH_SEED_BYTES);
// prepare msg_hash
scratch = CRYPTO_BYTES - SPHINCS256Config.MESSAGE_HASH_SEED_BYTES - SPHINCS256Config.CRYPTO_PUBLICKEYBYTES;
// cpy R
Array.Copy(R, 0, sm, scratch, SPHINCS256Config.MESSAGE_HASH_SEED_BYTES);
// construct and cpy pk
Tree.leafaddr b = new Tree.leafaddr();
b.level = SPHINCS256Config.N_LEVELS - 1;
b.subtree = 0;
b.subleaf = 0;
pk = scratch + SPHINCS256Config.MESSAGE_HASH_SEED_BYTES;
Array.Copy(tsk, SPHINCS256Config.SEED_BYTES, sm, pk, Horst.N_MASKS * SPHINCS256Config.HASH_BYTES);
Tree.treehash(hs, sm, pk + (Horst.N_MASKS * SPHINCS256Config.HASH_BYTES), SPHINCS256Config.SUBTREE_HEIGHT, tsk, b, sm, pk);
d = hs.getMessageHash();
d.BlockUpdate(sm, scratch, SPHINCS256Config.MESSAGE_HASH_SEED_BYTES + SPHINCS256Config.CRYPTO_PUBLICKEYBYTES);
d.BlockUpdate(m, 0, m.Length);
d.DoFinal(m_h, 0);
}
Tree.leafaddr a = new Tree.leafaddr();
a.level = SPHINCS256Config.N_LEVELS; // Use unique value $d$ for HORST address.
a.subleaf = (leafidx & (1UL << SPHINCS256Config.SUBTREE_HEIGHT) - 1);
a.subtree = (leafidx >> SPHINCS256Config.SUBTREE_HEIGHT);
int smlen = 0;
for (i = 0; i < SPHINCS256Config.MESSAGE_HASH_SEED_BYTES; i++)
{
sm[i] = R[i];
}
int smOff = SPHINCS256Config.MESSAGE_HASH_SEED_BYTES;
smlen += SPHINCS256Config.MESSAGE_HASH_SEED_BYTES;
Array.Copy(tsk, SPHINCS256Config.SEED_BYTES, masks, 0, Horst.N_MASKS * SPHINCS256Config.HASH_BYTES);
for (i = 0; i < (SPHINCS256Config.TOTALTREE_HEIGHT + 7) / 8; i++)
{
sm[smOff + i] = (byte)((leafidx >> 8 * i) & 0xff);
}
smOff += (SPHINCS256Config.TOTALTREE_HEIGHT + 7) / 8;
smlen += (SPHINCS256Config.TOTALTREE_HEIGHT + 7) / 8;
Seed.get_seed(hs, seed, 0, tsk, a);
int horst_sigbytes = Horst.horst_sign(hs, sm, smOff, root, seed, masks, m_h);
smOff += horst_sigbytes;
smlen += horst_sigbytes;
Wots w = new Wots();
for (i = 0; i < SPHINCS256Config.N_LEVELS; i++)
{
a.level = i;
Seed.get_seed(hs, seed, 0, tsk, a); //XXX: Don't use the same address as for horst_sign here!
w.wots_sign(hs, sm, smOff, root, seed, masks);
smOff += Wots.WOTS_SIGBYTES;
smlen += Wots.WOTS_SIGBYTES;
compute_authpath_wots(hs, root, sm, smOff, a, tsk, masks, SPHINCS256Config.SUBTREE_HEIGHT);
smOff += SPHINCS256Config.SUBTREE_HEIGHT * SPHINCS256Config.HASH_BYTES;
smlen += SPHINCS256Config.SUBTREE_HEIGHT * SPHINCS256Config.HASH_BYTES;
a.subleaf = (a.subtree & ((1UL << SPHINCS256Config.SUBTREE_HEIGHT) - 1));
a.subtree >>= SPHINCS256Config.SUBTREE_HEIGHT;
}
zerobytes(tsk, 0, SPHINCS256Config.CRYPTO_SECRETKEYBYTES);
return(sm);
}
internal static int horst_verify(HashFunctions hs, byte[] pk, byte[] sig, int sigOff, byte[] masks, byte[] m_hash)
{
byte[] buffer = new byte[32 * HASH_BYTES];
uint idx;
int i, j, k;
int sigOffset = sigOff + 64 * HASH_BYTES;
for (i = 0; i < HORST_K; i++)
{
idx = (uint)((m_hash[2 * i] & 0xff) + ((m_hash[2 * i + 1] & 0xff) << 8));
if ((idx & 1) == 0)
{
hs.hash_n_n(buffer, 0, sig, sigOffset);
for (k = 0; k < HASH_BYTES; k++)
{
buffer[HASH_BYTES + k] = sig[sigOffset + HORST_SKBYTES + k];
}
}
else
{
hs.hash_n_n(buffer, HASH_BYTES, sig, sigOffset);
for (k = 0; k < HASH_BYTES; k++)
{
buffer[k] = sig[sigOffset + HORST_SKBYTES + k];
}
}
sigOffset += HORST_SKBYTES + HASH_BYTES;
for (j = 1; j < HORST_LOGT - 6; j++)
{
idx = idx >> 1; // parent node
if ((idx & 1) == 0)
{
hs.hash_2n_n_mask(buffer, 0, buffer, 0, masks, 2 * (j - 1) * HASH_BYTES);
for (k = 0; k < HASH_BYTES; k++)
{
buffer[HASH_BYTES + k] = sig[sigOffset + k];
}
}
else
{
hs.hash_2n_n_mask(buffer, HASH_BYTES, buffer, 0, masks, 2 * (j - 1) * HASH_BYTES);
for (k = 0; k < HASH_BYTES; k++)
{
buffer[k] = sig[sigOffset + k];
}
}
sigOffset += HASH_BYTES;
}
idx = idx >> 1; // parent node
hs.hash_2n_n_mask(buffer, 0, buffer, 0, masks, 2 * (HORST_LOGT - 7) * HASH_BYTES);
for (k = 0; k < HASH_BYTES; k++)
{
if (sig[sigOff + idx * HASH_BYTES + k] != buffer[k])
{
for (k = 0; k < HASH_BYTES; k++)
{
pk[k] = 0;
}
return(-1);
}
}
}
// Compute root from level10
for (j = 0; j < 32; j++)
{
hs.hash_2n_n_mask(buffer, j * HASH_BYTES, sig, sigOff + 2 * j * HASH_BYTES, masks, 2 * (HORST_LOGT - 6) * HASH_BYTES);
}
// Hash from level 11 to 12
for (j = 0; j < 16; j++)
{
hs.hash_2n_n_mask(buffer, j * HASH_BYTES, buffer, 2 * j * HASH_BYTES, masks, 2 * (HORST_LOGT - 5) * HASH_BYTES);
}
// Hash from level 12 to 13
for (j = 0; j < 8; j++)
{
hs.hash_2n_n_mask(buffer, j * HASH_BYTES, buffer, 2 * j * HASH_BYTES, masks, 2 * (HORST_LOGT - 4) * HASH_BYTES);
}
// Hash from level 13 to 14
for (j = 0; j < 4; j++)
{
hs.hash_2n_n_mask(buffer, j * HASH_BYTES, buffer, 2 * j * HASH_BYTES, masks, 2 * (HORST_LOGT - 3) * HASH_BYTES);
}
// Hash from level 14 to 15
for (j = 0; j < 2; j++)
{
hs.hash_2n_n_mask(buffer, j * HASH_BYTES, buffer, 2 * j * HASH_BYTES, masks, 2 * (HORST_LOGT - 2) * HASH_BYTES);
}
// Hash from level 15 to 16
hs.hash_2n_n_mask(pk, 0, buffer, 0, masks, 2 * (HORST_LOGT - 1) * HASH_BYTES);
return(0);
}
internal static int horst_sign(HashFunctions hs,
byte[] sig, int sigOff, byte[] pk,
byte[] seed,
byte[] masks,
byte[] m_hash)
{
byte[] sk = new byte[HORST_T * HORST_SKBYTES];
uint idx;
int i, j, k;
int sigpos = sigOff;
byte[] tree = new byte[(2 * HORST_T - 1) * HASH_BYTES]; /* replace by something more memory-efficient? */
expand_seed(sk, seed);
// Build the whole tree and save it
// Generate pk leaves
for (i = 0; i < HORST_T; i++)
{
hs.hash_n_n(tree, (HORST_T - 1 + i) * HASH_BYTES, sk, i * HORST_SKBYTES);
}
long offset_in, offset_out;
for (i = 0; i < HORST_LOGT; i++)
{
offset_in = (1 << (HORST_LOGT - i)) - 1;
offset_out = (1 << (HORST_LOGT - i - 1)) - 1;
for (j = 0; j < (1 << (HORST_LOGT - i - 1)); j++)
{
hs.hash_2n_n_mask(tree, (int)((offset_out + j) * HASH_BYTES), tree, (int)((offset_in + 2 * j) * HASH_BYTES), masks, 2 * i * HASH_BYTES);
}
}
// First write 64 hashes from level 10 to the signature
for (j = 63 * HASH_BYTES; j < 127 * HASH_BYTES; j++)
{
sig[sigpos++] = tree[j];
}
// Signature consists of HORST_K parts; each part of secret key and HORST_LOGT-4 auth-path hashes
for (i = 0; i < HORST_K; i++)
{
idx = (uint)((m_hash[2 * i] & 0xff) + ((m_hash[2 * i + 1] & 0xff) << 8));
for (k = 0; k < HORST_SKBYTES; k++)
{
sig[sigpos++] = sk[idx * HORST_SKBYTES + k];
}
idx += (uint)(HORST_T - 1);
for (j = 0; j < HORST_LOGT - 6; j++)
{
idx = ((idx & 1) != 0) ? idx + 1 : idx - 1; // neighbor node
for (k = 0; k < HASH_BYTES; k++)
{
sig[sigpos++] = tree[idx * HASH_BYTES + k];
}
idx = (idx - 1) / 2; // parent node
}
}
for (i = 0; i < HASH_BYTES; i++)
{
pk[i] = tree[i];
}
return(HORST_SIGBYTES);
}
