pqcrypto/crypto_sign/rainbowIa-classic/clean/rainbow_keypair.c

/// @file rainbow_keypair.c
/// @brief implementations of functions in rainbow_keypair.h
///

#include "blas.h"
#include "blas_comm.h"
#include "rainbow_blas.h"
#include "rainbow_keypair.h"
#include "rainbow_keypair_computation.h"
#include "utils_prng.h"
#include <stdint.h>
#include <stdlib.h>
#include <string.h>


static
void generate_S_T( unsigned char *s_and_t, prng_t *prng0 ) {
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, s_and_t, _O1_BYTE * _O2 ); // S1
    s_and_t += _O1_BYTE * _O2;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, s_and_t, _V1_BYTE * _O1 ); // T1
    s_and_t += _V1_BYTE * _O1;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, s_and_t, _V1_BYTE * _O2 ); // T2
    s_and_t += _V1_BYTE * _O2;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, s_and_t, _O1_BYTE * _O2 ); // T3
}


static
unsigned generate_l1_F12( unsigned char *sk, prng_t *prng0 ) {
    unsigned n_byte_generated = 0;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, sk, _O1_BYTE * N_TRIANGLE_TERMS(_V1) );   // l1_F1
    sk += _O1_BYTE * N_TRIANGLE_TERMS(_V1);
    n_byte_generated += _O1_BYTE * N_TRIANGLE_TERMS(_V1);

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, sk, _O1_BYTE * _V1 * _O1 );  // l1_F2
    n_byte_generated += _O1_BYTE * _V1 * _O1;
    return n_byte_generated;
}


static
unsigned generate_l2_F12356( unsigned char *sk, prng_t *prng0 ) {
    unsigned n_byte_generated = 0;

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, sk, _O2_BYTE * N_TRIANGLE_TERMS(_V1) );   // l2_F1
    sk += _O2_BYTE * N_TRIANGLE_TERMS(_V1);
    n_byte_generated += _O2_BYTE * N_TRIANGLE_TERMS(_V1);

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, sk, _O2_BYTE * _V1 * _O1 ); // l2_F2
    sk += _O2_BYTE * _V1 * _O1;
    n_byte_generated += _O2_BYTE * _V1 * _O1;

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, sk, _O2_BYTE * _V1 * _O2 ); // l2_F3
    sk += _O2_BYTE * _V1 * _O1;
    n_byte_generated += _O2_BYTE * _V1 * _O1;

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, sk, _O2_BYTE * N_TRIANGLE_TERMS(_O1) );   // l2_F5
    sk += _O2_BYTE * N_TRIANGLE_TERMS(_O1);
    n_byte_generated += _O2_BYTE * N_TRIANGLE_TERMS(_O1);

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_gen( prng0, sk, _O2_BYTE * _O1 * _O2 ); // l2_F6
    n_byte_generated += _O2_BYTE * _O1 * _O2;

    return n_byte_generated;
}


static
void generate_B1_B2( unsigned char *sk, prng_t *prng0 ) {
    sk += generate_l1_F12( sk, prng0 );
    generate_l2_F12356( sk, prng0 );
}


//////////////////////////////////////////////////////////



void PQCLEAN_RAINBOWIACLASSIC_CLEAN_cpk_to_pk( pk_t *rpk, const cpk_t *cpk ) {
    // procedure:  cpk_t --> extcpk_t  --> pk_t

    // convert from cpk_t to extcpk_t
    ext_cpk_t pk;

    // setup prng
    prng_t prng0;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_set( &prng0, cpk->pk_seed, LEN_SKSEED );

    // generating parts of key with prng
    generate_l1_F12( pk.l1_Q1, &prng0 );
    // copying parts of key from input. l1_Q3, l1_Q5, l1_Q6, l1_Q9
    memcpy( pk.l1_Q3, cpk->l1_Q3, _O1_BYTE * ( _V1 * _O2 + N_TRIANGLE_TERMS(_O1) + _O1 * _O2 + N_TRIANGLE_TERMS(_O2) ) );

    // generating parts of key with prng
    generate_l2_F12356( pk.l2_Q1, &prng0 );
    // copying parts of key from input: l2_Q9
    memcpy( pk.l2_Q9, cpk->l2_Q9, _O2_BYTE * N_TRIANGLE_TERMS(_O2) );

    // convert from extcpk_t to pk_t
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_extcpk_to_pk( rpk, &pk );
}



/////////////////////////////////////////////////////////



static
void calculate_t4( unsigned char *t2_to_t4, const unsigned char *t1, const unsigned char *t3 ) {
    //  t4 = T_sk.t1 * T_sk.t3 - T_sk.t2
    unsigned char temp[_V1_BYTE + 32];
    unsigned char *t4 = t2_to_t4;
    for (unsigned i = 0; i < _O2; i++) { /// t3 width
        gfmat_prod( temp, t1, _V1_BYTE, _O1, t3 );
        gf256v_add( t4, temp, _V1_BYTE );
        t4 += _V1_BYTE;
        t3 += _O1_BYTE;
    }
}



static
void obsfucate_l1_polys( unsigned char *l1_polys, const unsigned char *l2_polys, unsigned n_terms, const unsigned char *s1 ) {
    unsigned char temp[_O1_BYTE + 32];
    while ( n_terms-- ) {
        gfmat_prod( temp, s1, _O1_BYTE, _O2, l2_polys );
        gf256v_add( l1_polys, temp, _O1_BYTE );
        l1_polys += _O1_BYTE;
        l2_polys += _O2_BYTE;
    }
}



///////////////////  Classic //////////////////////////////////


static
void _generate_secretkey( sk_t *sk, const unsigned char *sk_seed ) {
    memcpy( sk->sk_seed, sk_seed, LEN_SKSEED );

    // set up prng
    prng_t prng0;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_set( &prng0, sk_seed, LEN_SKSEED );

    // generating secret key with prng.
    generate_S_T( sk->s1, &prng0 );
    generate_B1_B2( sk->l1_F1, &prng0 );

    // clean prng
    memset( &prng0, 0, sizeof(prng_t) );
}


void PQCLEAN_RAINBOWIACLASSIC_CLEAN_generate_secretkey( sk_t *sk, const unsigned char *sk_seed ) {
    _generate_secretkey( sk, sk_seed );
    calculate_t4( sk->t4, sk->t1, sk->t3 );
}



void PQCLEAN_RAINBOWIACLASSIC_CLEAN_generate_keypair( pk_t *rpk, sk_t *sk, const unsigned char *sk_seed ) {
    _generate_secretkey( sk, sk_seed );

    // set up a temporary structure ext_cpk_t for calculating public key.
    ext_cpk_t pk;

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_calculate_Q_from_F( &pk, sk, sk );    // compute the public key in ext_cpk_t format.
    calculate_t4( sk->t4, sk->t1, sk->t3 );

    obsfucate_l1_polys( pk.l1_Q1, pk.l2_Q1, N_TRIANGLE_TERMS(_V1), sk->s1 );
    obsfucate_l1_polys( pk.l1_Q2, pk.l2_Q2, _V1 * _O1, sk->s1 );
    obsfucate_l1_polys( pk.l1_Q3, pk.l2_Q3, _V1 * _O2, sk->s1 );
    obsfucate_l1_polys( pk.l1_Q5, pk.l2_Q5, N_TRIANGLE_TERMS(_O1), sk->s1 );
    obsfucate_l1_polys( pk.l1_Q6, pk.l2_Q6, _O1 * _O2, sk->s1 );
    obsfucate_l1_polys( pk.l1_Q9, pk.l2_Q9, N_TRIANGLE_TERMS(_O2), sk->s1 );
    // so far, the pk contains the full pk but in ext_cpk_t format.

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_extcpk_to_pk( rpk, &pk );      // convert the public key from ext_cpk_t to pk_t.
}



/////////////////////   Cyclic   //////////////////////////////////


void PQCLEAN_RAINBOWIACLASSIC_CLEAN_generate_secretkey_cyclic( sk_t *sk, const unsigned char *pk_seed, const unsigned char *sk_seed ) {
    memcpy( sk->sk_seed, sk_seed, LEN_SKSEED );

    // prng for sk
    prng_t prng0;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_set( &prng0, sk_seed, LEN_SKSEED );
    generate_S_T( sk->s1, &prng0 );
    calculate_t4( sk->t4, sk->t1, sk->t3 );

    // prng for pk
    sk_t inst_Qs;
    sk_t *Qs = &inst_Qs;
    prng_t prng1;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_set( &prng1, pk_seed, LEN_PKSEED );
    generate_B1_B2( Qs->l1_F1, &prng1 );

    obsfucate_l1_polys( Qs->l1_F1, Qs->l2_F1, N_TRIANGLE_TERMS(_V1), sk->s1 );
    obsfucate_l1_polys( Qs->l1_F2, Qs->l2_F2, _V1 * _O1, sk->s1 );

    // calcuate the parts of sk according to pk.
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_calculate_F_from_Q( sk, Qs, sk );

    // clean prng for sk
    memset( &prng0, 0, sizeof(prng_t) );
}





void PQCLEAN_RAINBOWIACLASSIC_CLEAN_generate_keypair_cyclic( cpk_t *pk, sk_t *sk, const unsigned char *pk_seed, const unsigned char *sk_seed ) {
    memcpy( pk->pk_seed, pk_seed, LEN_PKSEED );

    // prng for sk
    prng_t prng;
    prng_t *prng0 = &prng;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_set( prng0, sk_seed, LEN_SKSEED );
    generate_S_T( sk->s1, prng0 );    // S,T:  only a part of sk

    unsigned char t2[sizeof(sk->t4)];
    memcpy( t2, sk->t4, _V1_BYTE * _O2 );        // temporarily store t2
    calculate_t4( sk->t4, sk->t1, sk->t3 );      // t2 <- t4

    // prng for pk
    sk_t inst_Qs;
    sk_t *Qs = &inst_Qs;
    prng_t *prng1 = &prng;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_prng_set( prng1, pk_seed, LEN_PKSEED );
    generate_B1_B2( Qs->l1_F1, prng1 );   // generating l1_Q1, l1_Q2, l2_Q1, l2_Q2, l2_Q3, l2_Q5, l2_Q6
    obsfucate_l1_polys( Qs->l1_F1, Qs->l2_F1, N_TRIANGLE_TERMS(_V1), sk->s1 );
    obsfucate_l1_polys( Qs->l1_F2, Qs->l2_F2, _V1 * _O1, sk->s1 );
    // so far, the Qs contains l1_F1, l1_F2, l2_F1, l2_F2, l2_F3, l2_F5, l2_F6.

    PQCLEAN_RAINBOWIACLASSIC_CLEAN_calculate_F_from_Q( sk, Qs, sk );            // calcuate the rest parts of secret key from Qs and S,T

    memcpy( sk->t4, t2, _V1_BYTE * _O2 );        // restore t2
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_calculate_Q_from_F_cyclic( pk, sk, sk );     // calculate the rest parts of public key: l1_Q3, l1_Q5, l1_Q6, l1_Q9, l2_Q9

    obsfucate_l1_polys( pk->l1_Q3, Qs->l2_F3, _V1 * _O2, sk->s1 );
    obsfucate_l1_polys( pk->l1_Q5, Qs->l2_F5, N_TRIANGLE_TERMS(_O1), sk->s1 );
    obsfucate_l1_polys( pk->l1_Q6, Qs->l2_F6, _O1 * _O2, sk->s1 );
    obsfucate_l1_polys( pk->l1_Q9, pk->l2_Q9, N_TRIANGLE_TERMS(_O2), sk->s1 );

    // clean
    memset( &prng, 0, sizeof(prng_t) );
}



void PQCLEAN_RAINBOWIACLASSIC_CLEAN_generate_compact_keypair_cyclic( cpk_t *pk, csk_t *rsk, const unsigned char *pk_seed, const unsigned char *sk_seed ) {
    memcpy( rsk->pk_seed, pk_seed, LEN_PKSEED );
    memcpy( rsk->sk_seed, sk_seed, LEN_SKSEED );
    sk_t sk;
    PQCLEAN_RAINBOWIACLASSIC_CLEAN_generate_keypair_cyclic( pk, &sk, pk_seed, sk_seed );
}