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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.4.
package org.bouncycastle.pqc.crypto.cmce;
import java.security.SecureRandom;
import org.bouncycastle.crypto.Xof;
import org.bouncycastle.crypto.digests.SHAKEDigest;
import org.bouncycastle.util.Arrays;
class CMCEEngine
{
private int SYS_N; // = 3488;
private int SYS_T; // = 64;
private int GFBITS; // = 12;
private int IRR_BYTES; // = SYS_T * 2;
private int COND_BYTES; // = (1 << (GFBITS-4))*(2*GFBITS - 1);
private int PK_NROWS; // = SYS_T*GFBITS;
private int PK_NCOLS; // = SYS_N - PK_NROWS;
private int PK_ROW_BYTES;// = (PK_NCOLS + 7)/8;
private int SYND_BYTES;// = (PK_NROWS + 7)/8;
private int GFMASK; // = (1 << GFBITS) - 1;
private int[] poly; // only needed for key pair gen
private final int defaultKeySize;
private GF gf;
private BENES benes;
private boolean usePadding;
private boolean countErrorIndices;
private boolean usePivots; // used for compression
public int getIrrBytes()
{
return IRR_BYTES;
}
public int getCondBytes()
{
return COND_BYTES;
}
public int getPrivateKeySize()
{
return COND_BYTES + IRR_BYTES + SYS_N / 8 + 40;
}
public int getPublicKeySize()
{
if (usePadding)
{
return PK_NROWS * ((SYS_N / 8 - ((PK_NROWS - 1) / 8)));
}
return PK_NROWS * PK_NCOLS / 8;
}
// public int getPublicKeySize(){ return PK_NCOLS*PK_NROWS/8; }
public int getCipherTextSize()
{
return SYND_BYTES;
}
public CMCEEngine(int m, int n, int t, int[] p, boolean usePivots, int defaultKeySize)
{
this.usePivots = usePivots;
this.SYS_N = n;
this.SYS_T = t;
this.GFBITS = m;
this.poly = p;
this.defaultKeySize = defaultKeySize;
IRR_BYTES = SYS_T * 2; // t * ceil(m/8)
COND_BYTES = (1 << (GFBITS - 4)) * (2 * GFBITS - 1);
PK_NROWS = SYS_T * GFBITS;
PK_NCOLS = SYS_N - PK_NROWS;
PK_ROW_BYTES = (PK_NCOLS + 7) / 8;
SYND_BYTES = (PK_NROWS + 7) / 8;
GFMASK = (1 << GFBITS) - 1;
if (GFBITS == 12)
{
gf = new GF12();
benes = new BENES12(SYS_N, SYS_T, GFBITS);
}
else
{
gf = new GF13();
benes = new BENES13(SYS_N, SYS_T, GFBITS);
}
usePadding = SYS_T % 8 != 0;
countErrorIndices = (1 << GFBITS) > SYS_N;
}
public byte[] generate_public_key_from_private_key(byte[] sk)
{
byte[] pk = new byte[getPublicKeySize()];
short[] pi = new short[1 << GFBITS];
long[] pivots = {0};
// generating the perm used to generate the private key
int[] perm = new int[1 << GFBITS];
byte[] hash = new byte[(SYS_N / 8) + ((1 << GFBITS) * 4)];
int hash_idx = hash.length - 32 - IRR_BYTES - ((1 << GFBITS) * 4);
Xof digest;
digest = new SHAKEDigest(256);
digest.update((byte)64);
digest.update(sk, 0, 32);
digest.doFinal(hash, 0, hash.length);
for (int i = 0; i < (1 << GFBITS); i++)
{
perm[i] = Utils.load4(hash, hash_idx + i * 4);
}
pk_gen(pk, sk, perm, pi, pivots);
return pk;
}
// generates the rest of the private key given the first 40 bytes
public byte[] decompress_private_key(byte[] sk)
{
byte[] reg_sk = new byte[getPrivateKeySize()];
System.arraycopy(sk, 0, reg_sk, 0, sk.length);
// s: n/8 (random string)
// a: COND_BYTES (field ordering) ((2m-1) * 2^(m-4))
// g: IRR_BYTES (polynomial) (t * 2)
// generate hash using the seed given in the sk (64 || first 32 bytes)
byte[] hash = new byte[(SYS_N / 8) + ((1 << GFBITS) * 4) + IRR_BYTES + 32];
int hash_idx = 0;
Xof digest;
digest = new SHAKEDigest(256);
digest.update((byte)64);
digest.update(sk, 0, 32); // input
digest.doFinal(hash, 0, hash.length);
// generate g
if (sk.length <= 40)
{
short[] field = new short[SYS_T];
byte[] reg_g = new byte[IRR_BYTES];
hash_idx = hash.length - 32 - IRR_BYTES;
for (int i = 0; i < SYS_T; i++)
{
field[i] = Utils.load_gf(hash, hash_idx + i * 2, GFMASK);
}
generate_irr_poly(field);
for (int i = 0; i < SYS_T; i++)
{
Utils.store_gf(reg_g, i * 2, field[i]);
}
System.arraycopy(reg_g, 0, reg_sk, 40, IRR_BYTES);
}
// generate a
if (sk.length <= 40 + IRR_BYTES)
{
int[] perm = new int[1 << GFBITS];
short[] pi = new short[1 << GFBITS];
hash_idx = hash.length - 32 - IRR_BYTES - ((1 << GFBITS) * 4);
for (int i = 0; i < (1 << GFBITS); i++)
{
perm[i] = Utils.load4(hash, hash_idx + i * 4);
}
if (usePivots)
{
long[] pivots = {0};
pk_gen(null, reg_sk, perm, pi, pivots);
}
else
{
long[] buf = new long[1 << GFBITS];
for (int i = 0; i < (1 << GFBITS); i++)
{
buf[i] = perm[i];
buf[i] <<= 31;
buf[i] |= i;
buf[i] &= 0x7fffffffffffffffL; // getting rid of signed longs
}
sort64(buf, 0, buf.length);
for (int i = 0; i < (1 << GFBITS); i++)
{
pi[i] = (short)(buf[i] & GFMASK);
}
}
byte[] out = new byte[COND_BYTES];
controlbitsfrompermutation(out, pi, GFBITS, 1 << GFBITS);
//copy the controlbits from the permutation to the private key
System.arraycopy(out, 0, reg_sk, IRR_BYTES + 40, out.length);
}
// reg s
System.arraycopy(hash, 0, reg_sk, getPrivateKeySize() - SYS_N / 8, SYS_N / 8);
return reg_sk;
}
public void kem_keypair(byte[] pk, byte[] sk, SecureRandom random)
{
// 1. Generate a uniform random l-bit string δ. (This is called a seed.)
byte[] seed_a = new byte[1];
byte[] seed_b = new byte[32];
seed_a[0] = 64;
random.nextBytes(seed_b);
//2. Output SeededKeyGen(δ).
// SeededKeyGen
byte[] E = new byte[(SYS_N / 8) + ((1 << GFBITS) * 4) + (SYS_T * 2) + 32];
int seedIndex, skIndex = 0;
byte[] prev_sk = seed_b;
long[] pivots = {0};
Xof digest = new SHAKEDigest(256);
while (true)
{
// SeededKeyGen - 1. Compute E = G(δ), a string of n + σ2q + σ1t + l bits. (3488 + 32*4096 + 16*64 + 256)
digest.update(seed_a, 0, seed_a.length);
digest.update(seed_b, 0, seed_b.length);
digest.doFinal(E, 0, E.length);
// Store the seeds generated
// SeededKeyGen - 2. Define δ′ as the last l bits of E.
// Update seed using the last 32 bytes (l) of E
// If anything fails, this set δ ←δ′ (the next last 32 bytes of E) and restart the algorithm.
seedIndex = E.length - 32;
seed_b = Arrays.copyOfRange(E, seedIndex, seedIndex + 32);
// store the previous last 32 bytes used as δ
System.arraycopy(prev_sk, 0, sk, 0, 32);
prev_sk = Arrays.copyOfRange(seed_b, 0, 32);
// (step 5 and 4 are swapped)
// SeededKeyGen - 5. Compute g from the next σ1t bits of E by the Irreducible algorithm. If this fails,
// set δ ←δ′ and restart the algorithm.
// Create Field which is an element in gf2^mt
// 2.4.1 Irreducible-polynomial generation
short[] field = new short[SYS_T];
int sigma1_t = E.length - 32 - (2 * SYS_T);
seedIndex = sigma1_t;
// Irreducible 2.4.1 - 1. Define βj = ∑m−1
// i=0 dσ1j+izi for each j ∈ {0,1,[],t −1}. (Within each group of σ1
// input bits, this uses only the first m bits.
for (int i = 0; i < SYS_T; i++)
{
field[i] = Utils.load_gf(E, sigma1_t + i * 2, GFMASK);
}
if (generate_irr_poly(field) == -1)
{
continue;
}
// storing poly to sk
skIndex = 32 + 8;
for (int i = 0; i < SYS_T; i++)
{
Utils.store_gf(sk, skIndex + i * 2, field[i]);
}
// SeededKeyGen - 4. Compute α1,[],αq from the next σ2q bits of E by the FieldOrdering algorithm.
// If this fails, set δ ←δ′ and restart the algorithm.
// Generate permutation
int[] perm = new int[(1 << GFBITS)];
seedIndex -= (1 << GFBITS) * 4;
// FieldOrdering 2.4.2 - 1. Take the first σ2 input bits b0,b1,[],bσ2−1 as a σ2-bit integer a0 =
// b0 + 2b1 + ··· + 2σ2−1bσ2−1, take the next σ2 bits as a σ2-bit integer a1, and so on through aq−1.
for (int i = 0; i < (1 << GFBITS); i++)
{
perm[i] = Utils.load4(E, seedIndex + i * 4);
}
// generating public key
short[] pi = new short[1 << GFBITS];
//8. Write Γ′ as (g,α′1,α′2,[],α′n)
if (pk_gen(pk, sk, perm, pi, pivots) == -1)
{
// System.out.println("FAILED GENERATING PUBLIC KEY");
continue;
}
// computing c using Nassimi-Sahni algorithm which is a
// parallel algorithms to set up the Benes permutation network
byte[] out = new byte[COND_BYTES];
controlbitsfrompermutation(out, pi, GFBITS, 1 << GFBITS);
//copy the controlbits from the permutation to the private key
System.arraycopy(out, 0, sk, IRR_BYTES + 40, out.length);
// storing the random string s
seedIndex -= SYS_N / 8;
System.arraycopy(E, seedIndex, sk, sk.length - SYS_N / 8, SYS_N / 8);
// This part is reserved for compression which is not implemented and is not required
if (!usePivots)
{
Utils.store8(sk, 32, 0xFFFFFFFFL);
}
else
{
Utils.store8(sk, 32, pivots[0]);
}
// 9. Output T as public key and (δ,c,g,α,s) as private key, where c = (cn−k−μ+1,[],cn−k)
// and α = (α′1,[],α′n,αn+1,[],αq
break;
}
}
// 2.2.3 Encoding subroutine
private void syndrome(byte[] cipher_text, byte[] pk, byte[] error_vector)
{
/*
2.2.3 Encoding subroutine
1. Define H = (In−k |T)
2. Compute and return C0 = He ∈Fn−k2 .
*/
short[] row = new short[SYS_N / 8];
int i, j, pk_ptr = 0;
byte b;
int tail = PK_NROWS % 8;
for (i = 0; i < SYND_BYTES; i++)
{
cipher_text[i] = 0;
}
for (i = 0; i < PK_NROWS; i++)
{
for (j = 0; j < SYS_N / 8; j++)
{
row[j] = 0;
}
for (j = 0; j < PK_ROW_BYTES; j++)
{
row[SYS_N / 8 - PK_ROW_BYTES + j] = pk[pk_ptr + j];
}
if (usePadding)
{
for (j = SYS_N / 8 - 1; j >= SYS_N / 8 - PK_ROW_BYTES; j--)
{
row[j] = (short)((((row[j] & 0xff) << tail) | ((row[j - 1] & 0xff) >>> (8 - tail))) & 0xff);
// System.out.printf("%04x ", row[j]);
}
}
row[i / 8] |= 1 << (i % 8);
b = 0;
for (j = 0; j < SYS_N / 8; j++)
{
b ^= row[j] & error_vector[j];
}
b ^= b >>> 4;
b ^= b >>> 2;
b ^= b >>> 1;
b &= 1;
cipher_text[i / 8] |= (b << (i % 8));
pk_ptr += PK_ROW_BYTES;
}
}
// 2.4.4 Fixed-weight-vector generation
private void generate_error_vector(byte[] error_vector, SecureRandom random)
{
byte[] buf_bytes;
short[] buf_nums = new short[SYS_T * 2];
short[] ind = new short[SYS_T];
byte[] val = new byte[SYS_T];
/*
2.4.4 Fixed-weight-vector generation
1. Generate σ1τ uniform random bits b0,b1,[],bσ1τ−1.
*/
while (true)
{
/*
2.4.4 Fixed-weight-vector generation
2. Define dj = ∑m−1
i=0 bσ1j+i2i for each j ∈{0,1,[],τ −1}.
*/
if (countErrorIndices)
{
buf_bytes = new byte[SYS_T * 4];
random.nextBytes(buf_bytes);
for (int i = 0; i < SYS_T * 2; i++)
{
buf_nums[i] = Utils.load_gf(buf_bytes, i * 2, GFMASK);
}
/*
2.4.4 Fixed-weight-vector generation
3. Define a0,a1,[],at−1 as the first t entries in d0,d1,[],dτ−1 in the range
{0,1,[],n −1}. If there are fewer than t such entries, restart the algorithm
*/
// moving and counting indices in the correct range
int count = 0;
for (int i = 0; i < SYS_T * 2 && count < SYS_T; i++)
{
if (buf_nums[i] < SYS_N)
{
ind[count++] = buf_nums[i];
}
}
if (count < SYS_T)
{
// System.out.println("Failed Encrypt indices wrong range");
continue;
}
}
else
{
buf_bytes = new byte[SYS_T * 2];
random.nextBytes(buf_bytes);
for (int i = 0; i < SYS_T; i++)
{
ind[i] = Utils.load_gf(buf_bytes, i * 2, GFMASK);
}
}
/*
2.4.4 Fixed-weight-vector generation
4. If a0,a1,[],at−1 are not all distinct, restart the algorithm.
*/
int eq = 0;
// check for repetition
for (int i = 1; i < SYS_T && eq != 1; i++)
{
for (int j = 0; j < i; j++)
{
if (ind[i] == ind[j])
{
eq = 1;
break;
}
}
}
if (eq == 0)
{
break;
}
else
{
// System.out.println("Failed Encrypt found duplicate");
}
}
/*
2.4.4 Fixed-weight-vector generation
5. Define e = (e0,e1,[],en−1) ∈ Fn2 as the weight-t vector such that eai = 1 for each i.
(Implementors are cautioned to compute e through arithmetic rather than variable-
time RAM lookups.)
*/
for (int i = 0; i < SYS_T; i++)
{
val[i] = (byte)(1 << (ind[i] & 7));
}
// System.out.print("e: ");
for (short i = 0; i < SYS_N / 8; i++)
{
error_vector[i] = 0;
for (int j = 0; j < SYS_T; j++)
{
short mask = same_mask32(i, (short)(ind[j] >> 3));
mask &= 0xff;
error_vector[i] |= val[j] & mask;
// System.out.printf("%02x ", mask);
}
}
}
private void encrypt(byte[] cipher_text, byte[] pk, byte[] error_vector, SecureRandom random)
{
/*
2.4.5 Encapsulation
1. Use FixedWeight to generate a vector e ∈Fn2 of weight t.
*/
// 2.4.4 Fixed-weight-vector generation
generate_error_vector(error_vector, random);
/*
2.4.5 Encapsulation
2. Compute C0 = Encode(e,T).
*/
syndrome(cipher_text, pk, error_vector);
}
// 2.4.5 Encapsulation
public int kem_enc(byte[] cipher_text, byte[] key, byte[] pk, SecureRandom random)
{
byte[] error_vector = new byte[SYS_N / 8];
byte mask;
int i, padding_ok = 0;
if (usePadding)
{
padding_ok = check_pk_padding(pk);
// System.out.println("padding_ok: " + padding_ok);
}
/*
2.4.5 Encapsulation
1. Use FixedWeight to generate a vector e ∈Fn2 of weight t.
2. Compute C0 = Encode(e,T).
*/
encrypt(cipher_text, pk, error_vector, random);
/*
2.4.5 Encapsulation
4. Compute K = H(1,e,C)
*/
// K = Hash((0x1 || e || C), 32)
Xof digest = new SHAKEDigest(256);
digest.update((byte)0x01);
digest.update(error_vector, 0, error_vector.length);
digest.update(cipher_text, 0, cipher_text.length); // input
digest.doFinal(key, 0, key.length); // output
if (usePadding)
{
//
// clear outputs (set to all 0's) if padding bits are not all zero
mask = (byte)padding_ok;
mask ^= 0xFF;
for (i = 0; i < SYND_BYTES; i++)
{
cipher_text[i] &= mask;
}
for (i = 0; i < 32; i++)
{
key[i] &= mask;
}
return padding_ok;
}
return 0;
}
// 2.3.3 Decapsulation
public int kem_dec(byte[] key, byte[] cipher_text, byte[] sk)
{
byte[] error_vector = new byte[SYS_N / 8];
byte[] preimage = new byte[1 + SYS_N/8 + SYND_BYTES];
int i, padding_ok = 0;
byte mask;
if (usePadding)
{
padding_ok = check_c_padding(cipher_text);
}
/*
2.3.3 Decapsulation
4. Compute e ←Decode(C0,Γ′). If e = ⊥, set e ←s and b ←0.
*/
// Decrypt
byte ret_decrypt = (byte)decrypt(error_vector, sk, cipher_text);
/*
2.3.3 Decapsulation
6. If C′1 6= C1, set e ←s and b ←0.
*/
short m;
m = ret_decrypt;
m -= 1;
m >>= 8;
m &= 0xff;
/*
2.3.3 Decapsulation
2. Set b ←1.
*/
preimage[0] = (byte)(m & 1);
for (i = 0; i < SYS_N / 8; i++)
{
preimage[1 + i] = (byte)((~m & sk[i + 40 + IRR_BYTES + COND_BYTES]) | (m & error_vector[i]));
}
for (i = 0; i < SYND_BYTES; i++)
{
preimage[1 + SYS_N / 8 + i] = cipher_text[i];
}
/*
2.3.3 Decapsulation
7. Compute K = H(b,e,C)
*/
// = SHAKE256(preimage, 32)
Xof digest = new SHAKEDigest(256);
digest.update(preimage, 0, preimage.length); // input
digest.doFinal(key, 0, key.length); // output
// clear outputs (set to all 1's) if padding bits are not all zero
if (usePadding)
{
mask = (byte)padding_ok;
for (i = 0; i < key.length; i++)
{
key[i] |= mask;
}
return padding_ok;
}
return 0;
}
// 2.2.4 Decoding subroutine
// Niederreiter decryption with the Berlekamp decoder
private int decrypt(byte[] error_vector, byte[] sk, byte[] cipher_text)
{
short[] g = new short[SYS_T + 1];
short[] L = new short[SYS_N];
short[] s = new short[SYS_T * 2];
short[] s_cmp = new short[SYS_T * 2];
short[] locator = new short[SYS_T + 1];
short[] images = new short[SYS_N];
short t;
byte[] r = new byte[SYS_N / 8];
/*
2.2.4 Decoding subroutine
1. Extend C0 to v = (C0,0,[],0) ∈Fn2 by appending k zeros.
*/
for (int i = 0; i < SYND_BYTES; i++)
{
r[i] = cipher_text[i];
}
for (int i = SYND_BYTES; i < SYS_N / 8; i++)
{
r[i] = 0;
}
for (int i = 0; i < SYS_T; i++)
{
g[i] = Utils.load_gf(sk, 40 + i * 2, GFMASK);
}
g[SYS_T] = 1;
/*
2.2.4 Decoding subroutine
2. Find the unique codeword c in the Goppa code defined by Γ′ that is at distance ≤t
from v. If there is no such codeword, return ⊥.
*/
// support gen
benes.support_gen(L, sk);
// compute syndrome
synd(s, g, L, r);
// compute minimal polynomial of syndrome
bm(locator, s);
// calculate the root for locator in L
root(images, locator, L);
/*
2.2.4 Decoding subroutine
3. Set e = v + c.
*/
for (int i = 0; i < SYS_N / 8; i++)
{
error_vector[i] = 0;
}
int w = 0;
for (int i = 0; i < SYS_N; i++)
{
t = (short)(gf.gf_iszero(images[i]) & 1);
error_vector[i / 8] |= t << (i % 8);
w += t;
}
// compute syndrome
synd(s_cmp, g, L, error_vector);
/*
2.2.4 Decoding subroutine
4. If wt(e) = t and C0 = He, return e. Otherwise return ⊥
*/
int check;
check = w;
check ^= SYS_T;
for (int i = 0; i < SYS_T * 2; i++)
{
check |= s[i] ^ s_cmp[i];
}
check -= 1;
check >>= 15;
check &= 0x1;
if ((check ^ 1) != 0)
{
//TODO throw exception?
// System.out.println("Decryption failed");
}
return check ^ 1;
}
private static int min(short a, int b)
{
if (a < b)
{
return a;
}
return b;
}
/* the Berlekamp-Massey algorithm */
/* input: s, sequence of field elements */
/* output: out, minimal polynomial of s */
private void bm(short[] out, short[] s)
{
short N = 0;
short L = 0;
short mle;
short mne;
short[] T = new short[SYS_T + 1];
short[] C = new short[SYS_T + 1];
short[] B = new short[SYS_T + 1];
short b = 1, d, f;
//
for (int i = 0; i < SYS_T + 1; i++)
{
C[i] = B[i] = 0;
}
B[1] = C[0] = 1;
//
for (N = 0; N < 2 * SYS_T; N++)
{
int d_ext = 0;
for (int i = 0; i <= min(N, SYS_T); i++)
{
d_ext ^= gf.gf_mul_ext(C[i], s[N - i]);
}
d = gf.gf_reduce(d_ext);
mne = d;
mne -= 1;
mne >>= 15;
mne &= 0x1;
mne -= 1;
mle = N;
mle -= 2 * L;
mle >>= 15;
mle &= 0x1;
mle -= 1;
mle &= mne;
for (int i = 0; i <= SYS_T; i++)
{
T[i] = C[i];
}
f = gf.gf_frac(b, d);
for (int i = 0; i <= SYS_T; i++)
{
C[i] ^= gf.gf_mul(f, B[i]) & mne;
}
L = (short)((L & ~mle) | ((N + 1 - L) & mle));
for (int i = SYS_T - 1; i >= 0; i--)
{
B[i + 1] = (short)((B[i] & ~mle) | (T[i] & mle));
}
B[0] = 0;
b = (short)((b & ~mle) | (d & mle));
}
for (int i = 0; i <= SYS_T; i++)
{
out[i] = C[SYS_T - i];
}
}
/* input: Goppa polynomial f, support L, received word r */
/* output: out, the syndrome of length 2t */
private void synd(short[] out, short[] f, short[] L, byte[] r)
{
{
short c = (short)(r[0] & 1);
short L_i = L[0];
short e = eval(f, L_i);
short e_inv = gf.gf_inv(gf.gf_sq(e));
short c_div_e = (short)(e_inv & -c);
out[0] = c_div_e;
for (int j = 1; j < 2 * SYS_T; j++)
{
c_div_e = gf.gf_mul(c_div_e, L_i);
out[j] = c_div_e;
}
}
for (int i = 1; i < SYS_N; i++)
{
short c = (short)((r[i / 8] >> (i % 8)) & 1);
short L_i = L[i];
short e = eval(f, L_i);
short e_inv = gf.gf_inv(gf.gf_sq(e));
short c_div_e = gf.gf_mul(e_inv, c);
out[0] ^= c_div_e;
for (int j = 1; j < 2 * SYS_T; j++)
{
c_div_e = gf.gf_mul(c_div_e, L_i);
out[j] ^= c_div_e;
}
}
}
private int mov_columns(byte[][] mat, short[] pi, long[] pivots)
{
int i, j, k, s, block_idx, row, tail;
long[] buf = new long[64],
ctz_list = new long[32];
long t, d, mask, one = 1;
byte[] tmp = new byte[9]; // Used for padding
row = PK_NROWS - 32;
block_idx = row / 8;
tail = row % 8;
// extract the 32x64 matrix
if (usePadding)
{
for (i = 0; i < 32; i++)
{
for (j = 0; j < 9; j++)
{
tmp[j] = mat[row + i][block_idx + j];
}
for (j = 0; j < 8; j++)
{
tmp[j] = (byte)(((tmp[j] & 0xff) >> tail) | (tmp[j + 1] << (8 - tail)));
}
buf[i] = Utils.load8(tmp, 0);
}
}
else
{
for (i = 0; i < 32; i++)
{
buf[i] = Utils.load8(mat[row + i], block_idx);
}
}
// compute the column indices of pivots by Gaussian elimination.
// the indices are stored in ctz_list
pivots[0] = 0;
for (i = 0; i < 32; i++)
{
t = buf[i];
for (j = i + 1; j < 32; j++)
{
t |= buf[j];
}
if (t == 0)
{
return -1; // return if buf is not full rank
}
ctz_list[i] = s = ctz(t);
pivots[0] |= one << ctz_list[i];
for (j = i + 1; j < 32; j++)
{
mask = (buf[i] >> s) & 1;
mask -= 1;
buf[i] ^= buf[j] & mask;
}
for (j = i + 1; j < 32; j++)
{
mask = (buf[j] >> s) & 1;
mask = -mask;
buf[j] ^= buf[i] & mask;
}
}
// updating permutation
for (j = 0; j < 32; j++)
{
for (k = j + 1; k < 64; k++)
{
d = pi[row + j] ^ pi[row + k];
d &= same_mask64((short)k, (short)ctz_list[j]);
pi[row + j] ^= d;
pi[row + k] ^= d;
}
}
// moving columns of mat according to the column indices of pivots
for (i = 0; i < PK_NROWS; i++)
{
if (usePadding)
{
for (k = 0; k < 9; k++)
{
tmp[k] = mat[i][block_idx + k];
}
for (k = 0; k < 8; k++)
{
tmp[k] = (byte)(((tmp[k] & 0xff) >> tail) | (tmp[k + 1] << (8 - tail)));
}
t = Utils.load8(tmp, 0);
}
else
{
t = Utils.load8(mat[i], block_idx);
}
for (j = 0; j < 32; j++)
{
d = t >> j;
d ^= t >> ctz_list[j];
d &= 1;
t ^= d << ctz_list[j];
t ^= d << j;
}
if (usePadding)
{
Utils.store8(tmp, 0, t);
mat[i][block_idx + 8] = (byte)(((mat[i][block_idx + 8] & 0xff) >>> tail << tail) | ((tmp[7] & 0xff) >>> (8 - tail)));
mat[i][block_idx + 0] = (byte)(((tmp[0] & 0xff) << tail) | ((mat[i][block_idx] & 0xff) << (8 - tail) >>> (8 - tail)));
for (k = 7; k >= 1; k--)
{
mat[i][block_idx + k] = (byte)(((tmp[k] & 0xff) << tail) | ((tmp[k - 1] & 0xff) >>> (8 - tail)));
}
}
else
{
Utils.store8(mat[i], block_idx, t);
}
}
return 0;
}
/* return number of trailing zeros of the non-zero input in */
private static int ctz(long in)
{
// int i, b, m = 0, r = 0;
//
// for (i = 0; i < 64; i++)
// {
// b = (int)((in >> i) & 1);
// m |= b;
// r += (m ^ 1) & (b ^ 1);
// }
//
// return r;
long m1 = 0x0101010101010101L, r8 = 0, x = ~in;
for (int i = 0; i < 8; ++i)
{
m1 &= x >>> i;
r8 += m1;
}
long m8 = r8 & 0x0808080808080808L;
m8 |= m8 >>> 1;
m8 |= m8 >>> 2;
long r = r8;
r8 >>>= 8;
r += r8 & m8;
for (int i = 2; i < 8; ++i)
{
m8 &= m8 >>> 8;
r8 >>>= 8;
r += r8 & m8;
}
return (int)r & 0xFF;
}
/* Used in mov columns*/
static private long same_mask64(short x, short y)
{
long mask;
mask = x ^ y;
mask -= 1;
mask >>>= 63;
mask = -mask;
return mask;
}
/* Used in error vector generation*/
private static byte same_mask32(short x, short y)
{
int mask;
mask = x ^ y;
mask -= 1;
mask >>>= 31;
mask = -mask;
return (byte)(mask & 0xFF);
}
private static void layer(short[] p, byte[] out, int ptrIndex, int s, int n)
{
int i, j;
int stride = 1 << s;
int index = 0;
int d, m;
for (i = 0; i < n; i += stride * 2)
{
for (j = 0; j < stride; j++)
{
d = p[i + j] ^ p[i + j + stride];
m = (out[ptrIndex + (index >> 3)] >> (index & 7)) & 1;
m = -m;
d &= m;
p[i + j] ^= d;
p[i + j + stride] ^= d;
index++;
}
}
}
private static void controlbitsfrompermutation(byte[] out, short[] pi, long w, long n)
{
int[] temp = new int[(int)(2 * n)];
short[] pi_test = new short[(int)n];
short diff;
int i;
int ptrIndex;
while (true)
{
for (i = 0; i < (((2 * w - 1) * n / 2) + 7) / 8; i++)
{
out[i] = 0;
}
cbrecursion(out, 0, 1, pi, 0, w, n, temp);
// check for correctness
for (i = 0; i < n; i++)
{
pi_test[i] = (short)i;
}
ptrIndex = 0;
for (i = 0; i < w; i++)
{
layer(pi_test, out, ptrIndex, i, (int)n);
ptrIndex += n >> 4;
}
for (i = (int)(w - 2); i >= 0; i--)
{
layer(pi_test, out, ptrIndex, i, (int)n);
ptrIndex += n >> 4;
}
diff = 0;
for (i = 0; i < n; i++)
{
diff |= pi[i] ^ pi_test[i];
}
if (diff == 0)
{
break;
}
}
}
static short get_q_short(int[] temp, int q_index)
{
int temp_index = q_index / 2;
if (q_index % 2 == 0)
{
return (short)temp[temp_index];
}
else
{
return (short)((temp[temp_index] & 0xffff0000) >> 16);
}
}
static void cbrecursion(byte[] out, long pos, long step, short[] pi, int qIndex, long w, long n, int[] temp)
{
long x, i, j, k;
if (w == 1)
{
out[(int)(pos >> 3)] ^= get_q_short(temp, qIndex) << (pos & 7);
return;
}
if (pi != null)
{
for (x = 0; x < n; ++x)
{
temp[(int)x] = ((pi[(int)x] ^ 1) << 16) | pi[(int)(x ^ 1)];
}
}
else
{
for (x = 0; x < n; ++x)
{
temp[(int)x] = ((get_q_short(temp, (int)(qIndex + x)) ^ 1) << 16) | get_q_short(temp, (int)((qIndex) + (x ^ 1)));
}
}
sort32(temp, 0, (int)n); /* A = (id<<16)+pibar */
for (x = 0; x < n; ++x)
{
int Ax = temp[(int)x];
int px = Ax & 0xffff;
int cx = px;
if (x < cx)
{
cx = (int)x;
}
temp[(int)(n + x)] = (px << 16) | cx;
}
for (x = 0; x < n; ++x)
{
temp[(int)x] = (int)((temp[(int)x] << 16) | x); /* A = (pibar<<16)+id */
}
sort32(temp, 0, (int)n); /* A = (id<<16)+pibar^-1 */
for (x = 0; x < n; ++x)
{
temp[(int)x] = (temp[(int)x] << 16) + (temp[(int)(n + x)] >> 16); /* A = (pibar^(-1)<<16)+pibar */
}
sort32(temp, 0, (int)n); /* A = (id<<16)+pibar^2 */
if (w <= 10)
{
for (x = 0; x < n; ++x)
{
temp[(int)(n + x)] = ((temp[(int)x] & 0xffff) << 10) | (temp[(int)(n + x)] & 0x3ff);
}
for (i = 1; i < w - 1; ++i)
{
/* B = (p<<10)+c */
for (x = 0; x < n; ++x)
{
temp[(int)x] = (int)(((temp[(int)(n + x)] & ~0x3ff) << 6) | x); /* A = (p<<16)+id */
}
sort32(temp, 0, (int)n); /* A = (id<<16)+p^{-1} */
for (x = 0; x < n; ++x)
{
temp[(int)x] = (temp[(int)x] << 20) | temp[(int)(n + x)]; /* A = (p^{-1}<<20)+(p<<10)+c */
}
sort32(temp, 0, (int)n); /* A = (id<<20)+(pp<<10)+cp */
for (x = 0; x < n; ++x)
{
int ppcpx = temp[(int)x] & 0xfffff;
int ppcx = (temp[(int)x] & 0xffc00) | (temp[(int)(n + x)] & 0x3ff);
if (ppcpx < ppcx)
{
ppcx = ppcpx;
}
temp[(int)(n + x)] = ppcx;
}
}
for (x = 0; x < n; ++x)
{
temp[(int)(n + x)] &= 0x3ff;
}
}
else
{
for (x = 0; x < n; ++x)
{
temp[(int)(n + x)] = (temp[(int)x] << 16) | (temp[(int)(n + x)] & 0xffff);
}
for (i = 1; i < w - 1; ++i)
{
/* B = (p<<16)+c */
for (x = 0; x < n; ++x)
{
temp[(int)x] = (int)((temp[(int)(n + x)] & ~0xffff) | x);
}
sort32(temp, 0, (int)n); /* A = (id<<16)+p^(-1) */
for (x = 0; x < n; ++x)
{
temp[(int)x] = (temp[(int)x] << 16) | (temp[(int)(n + x)] & 0xffff);
}
/* A = p^(-1)<<16+c */
if (i < w - 2)
{
//if loop 1 B
for (x = 0; x < n; ++x)
{
temp[(int)(n + x)] = (temp[(int)x] & ~0xffff) | (temp[(int)(n + x)] >> 16);
}
/* B = (p^(-1)<<16)+p */
sort32(temp, (int)n, (int)(n * 2)); /* B = (id<<16)+p^(-2) */
for (x = 0; x < n; ++x)
{
temp[(int)(n + x)] = (temp[(int)(n + x)] << 16) | (temp[(int)x] & 0xffff);
}
/* B = (p^(-2)<<16)+c */
}
sort32(temp, 0, (int)n);
/* A = id<<16+cp */
for (x = 0; x < n; ++x)
{
int cpx = (temp[(int)(n + x)] & ~0xffff) | (temp[(int)x] & 0xffff);
if (cpx < temp[(int)(n + x)])
{
temp[(int)(n + x)] = cpx;
}
}
}
for (x = 0; x < n; ++x)
{
temp[(int)(n + x)] &= 0xffff;
}
}
if (pi != null)
{
for (x = 0; x < n; ++x)
{
temp[(int)x] = (int)((((int)pi[(int)x]) << 16) + x);
}
}
else
{
for (x = 0; x < n; ++x)
{
temp[(int)x] = (int)(((get_q_short(temp, (int)(qIndex + x))) << 16) + x);
}
}
sort32(temp, 0, (int)n); /* A = (id<<16)+pi^(-1) */
for (j = 0; j < n / 2; ++j)
{
long _x = 2 * j;
int fj = temp[(int)(n + _x)] & 1; /* f[j] */
int Fx = (int)(_x + fj); /* F[x] */
int Fx1 = Fx ^ 1; /* F[x+1] */
out[(int)(pos >> 3)] ^= fj << (pos & 7);
pos += step;
temp[(int)(n + _x)] = (temp[(int)_x] << 16) | Fx;
temp[(int)(n + _x + 1)] = (temp[(int)(_x + 1)] << 16) | Fx1;
}
/* B = (pi^(-1)<<16)+F */
sort32(temp, (int)n, (int)(n * 2)); /* B = (id<<16)+F(pi) */
pos += (2 * w - 3) * step * (n / 2);
for (k = 0; k < n / 2; ++k)
{
long y = 2 * k;
int lk = temp[(int)(n + y)] & 1; /* l[k] */
int Ly = (int)(y + lk); /* L[y] */
int Ly1 = Ly ^ 1; /* L[y+1] */
out[(int)(pos >> 3)] ^= lk << (pos & 7);
pos += step;
temp[(int)y] = (Ly << 16) | (temp[(int)(n + y)] & 0xffff);
temp[(int)(y + 1)] = (Ly1 << 16) | (temp[(int)(n + y + 1)] & 0xffff);
}
/* A = (L<<16)+F(pi) */
sort32(temp, 0, (int)n); /* A = (id<<16)+F(pi(L)) = (id<<16)+M */
pos -= (2 * w - 2) * step * (n / 2);
short[] q = new short[(int)n * 4];
for (i = 0/*n + n/4*/; i < n * 2; i++)
{
q[(int)(i * 2 + 0)] = (short)temp[(int)i];
q[(int)(i * 2 + 1)] = (short)((temp[(int)i] & 0xffff0000) >> 16);
}
for (j = 0; j < n / 2; ++j)
{
q[(int)j] = (short)((temp[(int)(2 * j)] & 0xffff) >>> 1);
q[(int)(j + n / 2)] = (short)((temp[(int)(2 * j + 1)] & 0xffff) >>> 1);
}
for (i = 0; i < n / 2; i++)
{
temp[(int)(n + n / 4 + i)] = (((int)q[(int)(i * 2 + 1)]) << 16) | ((int)q[(int)(i * 2)]);
}
cbrecursion(out, pos, step * 2, null, (int)(n + n / 4) * 2, w - 1, n / 2, temp);
cbrecursion(out, pos + step, step * 2, null, (int)((n + n / 4) * 2 + n / 2), w - 1, n / 2, temp);
}
private int pk_gen(byte[] pk, byte[] sk, int[] perm, short[] pi, long[] pivots)
{
short[] g = new short[SYS_T + 1]; // Goppa polynomial
int i, j, k;
g[SYS_T] = 1;
for (i = 0; i < SYS_T; i++)
{
g[i] = Utils.load_gf(sk, 40 + i * 2, GFMASK);
}
// Create buffer
long[] buf = new long[1 << GFBITS];
for (i = 0; i < (1 << GFBITS); i++)
{
buf[i] = perm[i];
buf[i] <<= 31;
buf[i] |= i;
buf[i] &= 0x7fffffffffffffffL; // getting rid of signed longs
}
// sort32 the buffer
// FieldOrdering 2.4.2 - 3. sort32 the pairs (ai,i) in lexicographic order to obtain pairs (aπ(i),π(i))
// where π is a permutation of {0,1,[],q −1}
sort64(buf, 0, buf.length);
// FieldOrdering 2.4.2 - 2. If a0,a1,[],aq−1 are not distinct, return ⊥.
for (i = 1; i < (1 << GFBITS); i++)
{
if ((buf[i - 1] >> 31) == (buf[i] >> 31))
{
// System.out.println("FAIL 1");
return -1;
}
}
// FieldOrdering 2.4.2 - 4.
short[] L = new short[SYS_N];
for (i = 0; i < (1 << GFBITS); i++)
{
pi[i] = (short)(buf[i] & GFMASK);
}
for (i = 0; i < SYS_N; i++)
{
L[i] = Utils.bitrev(pi[i], GFBITS);
}
// filling matrix
short[] inv = new short[SYS_N];
root(inv, g, L);
for (i = 0; i < SYS_N; i++)
{
inv[i] = gf.gf_inv(inv[i]);
}
byte[][] mat = new byte[PK_NROWS][(SYS_N / 8)];
byte b;
for (i = 0; i < PK_NROWS; i++)
{
for (j = 0; j < SYS_N / 8; j++)
{
mat[i][j] = 0;
}
}
for (i = 0; i < SYS_T; i++)
{
for (j = 0; j < SYS_N; j += 8)
{
for (k = 0; k < GFBITS; k++)
{
b = (byte)((inv[j + 7] >>> k) & 1);
b <<= 1;
b |= (inv[j + 6] >>> k) & 1;
b <<= 1;
b |= (inv[j + 5] >>> k) & 1;
b <<= 1;
b |= (inv[j + 4] >>> k) & 1;
b <<= 1;
b |= (inv[j + 3] >>> k) & 1;
b <<= 1;
b |= (inv[j + 2] >>> k) & 1;
b <<= 1;
b |= (inv[j + 1] >>> k) & 1;
b <<= 1;
b |= (inv[j + 0] >>> k) & 1;
mat[i * GFBITS + k][j / 8] = b;
}
}
for (j = 0; j < SYS_N; j++)
{
inv[j] = gf.gf_mul(inv[j], L[j]);
}
}
// gaussian elimination
int row, c;
byte mask;
for (row = 0; row < PK_NROWS; row++)
{
i = row >>> 3;
j = row & 7;
if (usePivots)
{
if (row == PK_NROWS - 32)
{
if (mov_columns(mat, pi, pivots) != 0)
{
// System.out.println("failed mov column!");
return -1;
}
}
}
for (k = row + 1; k < PK_NROWS; k++)
{
mask = (byte)(mat[row][i] ^ mat[k][i]);
mask >>= j;
mask &= 1;
mask = (byte)-mask;
for (c = 0; c < SYS_N / 8; c++)
{
mat[row][c] ^= mat[k][c] & mask;
}
}
// 7. Compute (T,cn−k−μ+1,[],cn−k,Γ′) ← MatGen(Γ). If this fails, set δ ← δ′ and
// restart the algorithm.
if (((mat[row][i] >> j) & 1) == 0) // return if not systematic
{
// System.out.println("FAIL 2\n");
return -1;
}
for (k = 0; k < PK_NROWS; k++)
{
if (k != row)
{
mask = (byte)(mat[k][i] >> j);
mask &= 1;
mask = (byte)-mask;
for (c = 0; c < SYS_N / 8; c++)
{
mat[k][c] ^= mat[row][c] & mask;
}
}
}
}
// FieldOrdering 2.4.2 - 5. Output (α1,α2,[],αq)
if (pk != null)
{
if (usePadding)
{
int pk_index = 0, tail = PK_NROWS % 8;
for (i = 0; i < PK_NROWS; i++)
{
for (j = (PK_NROWS - 1) / 8; j < SYS_N / 8 - 1; j++)
{
pk[pk_index++] = (byte)(((mat[i][j] & 0xff) >>> tail) | (mat[i][j + 1] << (8 - tail)));
}
pk[pk_index++] = (byte)((mat[i][j] & 0xff) >>> tail);
}
}
else
{
// for (i = 0; i < PK_NROWS; i++)
// {
// k = 0;
// for (j = 0; j < (((SYS_N - PK_NROWS) + 7) / 8); j++)
// {
// pk[i * (((SYS_N - PK_NROWS) + 7) / 8) + k] = mat[i][j + PK_NROWS / 8];
// k++;
// }
// }
int count = (SYS_N - PK_NROWS + 7) / 8;
for (i = 0; i < PK_NROWS; i++)
{
System.arraycopy(mat[i], PK_NROWS / 8, pk, count * i, count);
}
}
}
return 0;
}
private short eval(short[] f, short a)
{
short r = f[SYS_T];
for (int i = SYS_T - 1; i >= 0; i--)
{
r = (short)(gf.gf_mul(r, a) ^ f[i]);
}
return r;
}
private void root(short[] out, short[] f, short[] L)
{
for (int i = 0; i < SYS_N; i++)
{
out[i] = eval(f, L[i]);
}
}
private int generate_irr_poly(short[] field)
{
// Irreducible 2.4.1 - 2. Define β = β0 + β1y + ···+ βt−1yt−1 ∈Fq[y]/F(y).
// generating poly
short[][] m = new short[SYS_T + 1][SYS_T];
// filling matrix
{
m[0][0] = 1;
// for (int i = 1; i < SYS_T; i++)
// {
// m[0][i] = 0;
// }
System.arraycopy(field, 0, m[1], 0, SYS_T);
int[] temp = new int[SYS_T * 2 - 1];
int j = 2;
while (j < SYS_T)
{
gf.gf_sqr_poly(SYS_T, poly, m[j], m[j >>> 1], temp);
gf.gf_mul_poly(SYS_T, poly, m[j + 1], m[j], field, temp);
j += 2;
}
if (j == SYS_T)
{
gf.gf_sqr_poly(SYS_T, poly, m[j], m[j >>> 1], temp);
}
}
// Irreducible 2.4.1 - 3. Compute the minimal polynomial g of β over Fq. (By definition g is monic and irre-
// ducible, and g(β) = 0.)
// gaussian
for (int j = 0; j < SYS_T; j++)
{
for (int k = j + 1; k < SYS_T; k++)
{
short mask = gf.gf_iszero(m[j][j]);
for (int c = j; c < SYS_T + 1; c++)
{
m[c][j] ^= (short)(m[c][k] & mask);
}
}
// Irreducible 2.4.1 - 4. Return g if g has degree t. Otherwise return ⊥
if (m[j][j] == 0) // return if not systematic
{
// System.out.println("FAILED GENERATING IRR POLY");
return -1;
}
short inv = gf.gf_inv(m[j][j]);
for (int c = j; c < SYS_T + 1; c++)
{
m[c][j] = gf.gf_mul(m[c][j], inv);
}
for (int k = 0; k < SYS_T; k++)
{
if (k != j)
{
short t = m[j][k];
for (int c = j; c <= SYS_T; c++)
{
m[c][k] ^= gf.gf_mul(m[c][j], t);
}
}
}
}
System.arraycopy(m[SYS_T], 0, field, 0, SYS_T);
return 0;
}
/* check if the padding bits of pk are all zero */
int check_pk_padding(byte[] pk)
{
byte b;
int i, ret;
b = 0;
for (i = 0; i < PK_NROWS; i++)
{
b |= pk[i * PK_ROW_BYTES + PK_ROW_BYTES - 1];
}
b = (byte)((b & 0xff) >>> (PK_NCOLS % 8));
b -= 1;
b = (byte)((b & 0xff) >>> 7);
ret = b;
return ret - 1;
}
/* check if the padding bits of c are all zero */
int check_c_padding(byte[] c)
{
byte b;
int ret;
b = (byte)((c[SYND_BYTES - 1] & 0xff) >>> (PK_NROWS % 8));
b -= 1;
b = (byte)((b & 0xff) >>> 7);
ret = b;
return ret - 1;
}
public int getDefaultSessionKeySize()
{
return defaultKeySize;
}
private static void sort32(int[] temp, int from, int to)
{
int top,p,q,r,i;
int n = to - from;
if (n < 2) return;
top = 1;
while (top < n - top) top += top;
for (p = top;p > 0;p >>>= 1)
{
for (i = 0;i < n - p;++i)
{
if ((i & p) == 0)
{
int ab = temp[from + i + p] ^ temp[from + i];
int c = temp[from + i + p] - temp[from + i];
c ^= ab & (c ^ temp[from + i + p]);
c >>= 31;
c &= ab;
temp[from + i] ^= c;
temp[from + i + p] ^= c;
}
}
i = 0;
for (q = top;q > p;q >>>= 1)
{
for (;i < n - q;++i)
{
if ((i & p) == 0)
{
int a = temp[from + i + p];
for (r = q;r > p;r >>>= 1)
{
int ab = temp[from + i + r] ^ a;
int c = temp[from + i + r] - a;
c ^= ab & (c ^ temp[from + i + r]);
c >>= 31;
c &= ab;
a ^= c;
temp[from + i + r] ^= c;
}
temp[from + i + p] = a;
}
}
}
}
}
private static void sort64(long[] temp, int from, int to)
{
int top,p,q,r,i;
int n = to - from;
if (n < 2) return;
top = 1;
while (top < n - top) top += top;
for (p = top;p > 0;p >>>= 1)
{
for (i = 0;i < n - p;++i)
{
if ((i & p) == 0)
{
long c = temp[from + i + p] - temp[from + i];
c >>>= 63;
c = -c;
c &= temp[from + i] ^ temp[from + i + p];
temp[from + i] ^= c;
temp[from + i + p] ^= c;
}
}
i = 0;
for (q = top;q > p;q >>>= 1)
{
for (;i < n - q;++i)
{
if ((i & p) == 0)
{
long a = temp[from + i + p];
for (r = q;r > p;r >>>= 1)
{
long c = temp[from + i + r] - a;
c >>>= 63;
c = -c;
c &= a ^ temp[from + i + r];
a ^= c;
temp[from + i + r] ^= c;
}
temp[from + i + p] = a;
}
}
}
}
}
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