ed448goldilocks/test/test_scalarmul.c

#include "test.h"

#include <stdio.h>

#include "scalarmul.h"
#include "ec_point.h"
#include "p448.h"
#include "crandom.h"

/* 0 = succeed, 1 = inval, -1 = fail */
static int
single_scalarmul_compatibility_test (
    const struct p448_t *base,
    const word_t *scalar,
    int nbits
) {
    struct tw_extensible_t text, work;
    struct p448_t mont, ct, vl, vt;
    
    int ret = 0, i;
    mask_t succ, succm;
    
    const struct p448_t
    sqrt_d_minus_1 = {{
        U58LE(0xd2e21836749f46),
        U58LE(0x888db42b4f0179),
        U58LE(0x5a189aabdeea38),
        U58LE(0x51e65ca6f14c06),
        U58LE(0xa49f7b424d9770),
        U58LE(0xdcac4628c5f656),
        U58LE(0x49443b8748734a),
        U58LE(0x12fec0c0b25b7a)
    }};
    
    succ = deserialize_and_twist_approx(&text, &sqrt_d_minus_1, base);
    
    succm = montgomery_ladder(&mont,base,scalar,nbits,1);
    
    if (succ != succm) {
        youfail();
        printf("    Deserialize_and_twist_approx succ=%d, montgomery_ladder succ=%d\n",
            (int)-succ, (int)-succm);
        printf("    nbits = %d\n", nbits);
        p448_print("    base", base);
        scalar_print("    scal", scalar, (nbits+WORD_BITS-1)/WORD_BITS);
        return -1;
    }
    
    if (!succ) {
        return 1;
    }
    
    struct { int n,t,s; } params[] = {{5,5,18},{3,5,30},{4,4,28},{1,2,224}};
    const int nparams = sizeof(params)/sizeof(params[0]);
    struct fixed_base_table_t fbt;
    struct p448_t fbout[nparams], wout[6];
    memset(&fbt, 0, sizeof(fbt));
    memset(&fbout, 0, sizeof(fbout));
    memset(&wout, 0, sizeof(wout));
        
    /* compute using combs */
    for (i=0; i<nparams; i++) {
        int n=params[i].n, t=params[i].t, s=params[i].s;
        succ = precompute_fixed_base(&fbt, &text, n, t, s, NULL);
        if (!succ) {
            youfail();
            printf("    Failed to precompute_fixed_base(%d,%d,%d)\n", n, t, s);
            continue;
        }
        
        succ = scalarmul_fixed_base(&work, scalar, nbits, &fbt);
        destroy_fixed_base(&fbt);
        if (!succ) {
            youfail();
            printf("    Failed to scalarmul_fixed_base(%d,%d,%d)\n", n, t, s);
            continue;
        }
        
        untwist_and_double_and_serialize(&fbout[i], &work);
    }
    
    /* compute using precomp wNAF */
    for (i=0; i<=5; i++) {
        struct tw_niels_t pre[1<<i];
        
        succ = precompute_fixed_base_wnaf(pre, &text, i);
        if (!succ) {
            youfail();
            printf("    Failed to precompute_fixed_base_wnaf(%d)\n", i);
            continue;
        }
        
        scalarmul_fixed_base_wnaf_vt(&work, scalar, nbits, pre, i);
        
        untwist_and_double_and_serialize(&wout[i], &work);
    }
    
    mask_t consistent = MASK_SUCCESS;
    
    if (nbits == 448) {
        /* window methods currently only work on 448 bits. */
        copy_tw_extensible(&work, &text);
        scalarmul(&work, scalar);
        untwist_and_double_and_serialize(&ct, &work);
        
        copy_tw_extensible(&work, &text);
        scalarmul_vlook(&work, scalar);
        untwist_and_double_and_serialize(&vl, &work);
        
        copy_tw_extensible(&work, &text);
        scalarmul_vt(&work, scalar);
        untwist_and_double_and_serialize(&vt, &work);
        
    
        /* check consistency mont vs window */
        consistent &= p448_eq(&mont, &ct);
        consistent &= p448_eq(&mont, &vl);
        consistent &= p448_eq(&mont, &vt);
    }
    
    /* check consistency mont vs combs */
    for (i=0; i<nparams; i++) {
        consistent &= p448_eq(&mont,&fbout[i]);
    }
    
    /* check consistency mont vs wNAF */
    for (i=0; i<6; i++) {
        consistent &= p448_eq(&mont,&wout[i]);
    }
    
    /* If inconsistent, complain. */
    if (!consistent) {
        youfail();
        printf("    Failed scalarmul consistency test with nbits=%d.\n",nbits);
        p448_print("    base", base);
        scalar_print("    scal", scalar, (nbits+WORD_BITS-1)/WORD_BITS);
        p448_print("    mont", &mont);
        
        for (i=0; i<nparams; i++) {
            printf("    With n=%d, t=%d, s=%d:\n", params[i].n, params[i].t, params[i].s);
            p448_print("    out ", &fbout[i]);
        }
        
        for (i=0; i<6; i++) {
            printf("    With w=%d:\n",i);
            p448_print("    wNAF", &wout[i]);
        }
        
    
        if (nbits == 448) {
            p448_print("    ct ", &ct);
            p448_print("    vl ", &vl);
            p448_print("    vt ", &vt);
        }
        
        ret = -1;
    }
    
    return ret;
}

/* 0 = succeed, 1 = inval, -1 = fail */
static int
single_scalarmul_commutativity_test (
    const struct p448_t *base,
    const word_t *scalar1,
    int nbits1,
    int ned1,
    const word_t *scalar2,
    int nbits2,
    int ned2
) {
    struct p448_t m12, m21, tmp1, tmp2;
    mask_t succ12a = montgomery_ladder(&tmp1,base,scalar1,nbits1,ned1);
    mask_t succ12b = montgomery_ladder(&m12,&tmp1,scalar2,nbits2,ned2);
    
    mask_t succ21a = montgomery_ladder(&tmp2,base,scalar2,nbits2,ned2);
    mask_t succ21b = montgomery_ladder(&m21,&tmp2,scalar1,nbits1,ned1);
    
    mask_t succ12 = succ12a & succ12b, succ21 = succ21a & succ21b;
    
    if (succ12 != succ21) {
        youfail();
        printf("    Failed scalarmul commutativity test with (nbits,ned) = (%d,%d), (%d,%d).\n",
            nbits1,ned1,nbits2,ned2);
        p448_print("    base", base);
        p448_print("    tmp1", &tmp1);
        p448_print("    tmp2", &tmp2);
        scalar_print("    sca1", scalar1, (nbits1+WORD_BITS-1)/WORD_BITS);
        scalar_print("    sca2", scalar2, (nbits1+WORD_BITS-1)/WORD_BITS);
        printf("    good = ((%d,%d),(%d,%d))\n", (int)-succ12a,
            (int)-succ12b, (int)-succ21a, (int)-succ21b);
        return -1;
    } else if (!succ12) {
        // printf("    (nbits,ned) = (%d,%d), (%d,%d).\n", nbits1,ned1,nbits2,ned2);
        // printf("    succ = (%d,%d), (%d,%d).\n", (int)-succ12a, (int)-succ12b, (int)-succ21a, (int)-succ21b);
        return 1;
    }
    
    mask_t consistent = p448_eq(&m12,&m21);
    if (consistent) {
        return 0;
    } else {
        youfail();
        printf("    Failed scalarmul commutativity test with (nbits,ned) = (%d,%d), (%d,%d).\n",
            nbits1,ned1,nbits2,ned2);
        p448_print("    base", base);
        scalar_print("    sca1", scalar1, (nbits1+WORD_BITS-1)/WORD_BITS);
        scalar_print("    sca2", scalar2, (nbits1+WORD_BITS-1)/WORD_BITS);
        p448_print("    m12 ", &m12);
        p448_print("    m21 ", &m21);
        return -1;
    }
}

int test_scalarmul_commutativity () {
    int i,j,k,got;
    
    struct crandom_state_t crand;
    crandom_init_from_buffer(&crand, "scalarmul_commutativity_test RNG");
    
    for (i=0; i<=448; i+=7) {
        for (j=0; j<=448; j+=7) {
            got = 0;
            
            for (k=0; k<128 && !got; k++) {
                uint8_t ser[56];
                word_t scalar1[7], scalar2[7];
                crandom_generate(&crand, ser, sizeof(ser));
                crandom_generate(&crand, (uint8_t *)scalar1, sizeof(scalar1));
                crandom_generate(&crand, (uint8_t *)scalar2, sizeof(scalar2));
            
                p448_t base;
                mask_t succ = p448_deserialize(&base, ser);
                if (!succ) continue;
            
                int ret = single_scalarmul_commutativity_test (&base, scalar1, i, i%3, scalar2, j, j%3);
                got = !ret;
                if (ret == -1) return -1;
            }

            if (!got) {
                youfail();
                printf("    Unlikely: rejected 128 scalars in a row.\n");
                return -1;
            }
            
        }
    }
    
    return 0;
}

int test_scalarmul_compatibility () {
    int i,j,k,got;
    
    struct crandom_state_t crand;
    crandom_init_from_buffer(&crand, "scalarmul_compatibility_test RNG");
    
    for (i=0; i<=448; i+=7) {
        for (j=0; j<=20; j++) {
            got = 0;
            
            for (k=0; k<128 && !got; k++) {
                uint8_t ser[56];
                word_t scalar[7];
                crandom_generate(&crand, ser, sizeof(ser));
                crandom_generate(&crand, (uint8_t *)scalar, sizeof(scalar));
            
                p448_t base;
                mask_t succ = p448_deserialize(&base, ser);
                if (!succ) continue;
            
                int ret = single_scalarmul_compatibility_test (&base, scalar, i);
                got = !ret;
                if (ret == -1) return -1;
            }

            if (!got) {
                youfail();
                printf("    Unlikely: rejected 128 scalars in a row.\n");
                return -1;
            }
            
        }
    }
    
    return 0;
}