diff options
Diffstat (limited to 'pyecsca/codegen/bn/bn.c')
| -rw-r--r-- | pyecsca/codegen/bn/bn.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/pyecsca/codegen/bn/bn.c b/pyecsca/codegen/bn/bn.c index 1247c5d..22e1d49 100644 --- a/pyecsca/codegen/bn/bn.c +++ b/pyecsca/codegen/bn/bn.c @@ -135,6 +135,174 @@ bn_err bn_mod(const bn_t *one, const bn_t *mod, bn_t *out) { return mp_mod(one, mod, out); } +bn_err bn_red_init(red_t *out) { + #if REDUCTION == RED_MONTGOMERY + return bn_init(&out->montgomery_renorm); + #elif REDUCTION == RED_BARRETT + return bn_init(&out->barret); + #endif + return BN_OKAY; +} + +bn_err bn_red_setup(const bn_t *mod, red_t *out) { + #if REDUCTION == RED_MONTGOMERY + bn_err err; + if ((err = mp_montgomery_setup(mod, &out->montgomery_digit)) != BN_OKAY) { + return err; + } + if ((err = mp_montgomery_calc_normalization(&out->montgomery_renorm, mod)) != BN_OKAY) { + return err; + } + return mp_sqrmod(&out->montgomery_renorm, mod, &out->montgomery_renorm_sqr); + #elif REDUCTION == RED_BARRETT + return mp_reduce_setup(mod, &out->barret); + #endif + return BN_OKAY; +} + +bn_err bn_red_encode(bn_t *one, const bn_t *mod, const red_t *red) { + #if REDUCTION == RED_MONTGOMERY + return mp_mulmod(one, &red->montgomery_renorm, mod, one); + #else + return BN_OKAY; + #endif +} + +bn_err bn_red_decode(bn_t *one, const bn_t *mod, const red_t *red) { + #if REDUCTION == RED_MONTGOMERY + return mp_montgomery_reduce(one, mod, red->montgomery_digit); + #else + return BN_OKAY; + #endif +} + +bn_err bn_red_add(const bn_t *one, const bn_t *other, const bn_t *mod, const red_t *red, bn_t *out) { + bn_err err; + if ((err = mp_add(one, other, out)) != BN_OKAY) { + return err; + } + if (mp_cmp(out, mod) == MP_GT) { + return mp_sub(out, mod, out); + } else { + return err; + } +} + +bn_err bn_red_sub(const bn_t *one, const bn_t *other, const bn_t *mod, const red_t *red, bn_t *out) { + bn_err err; + if ((err = mp_sub(one, other, out)) != BN_OKAY) { + return err; + } + if (mp_cmp_d(out, 0) == MP_LT) { + return mp_add(out, mod, out); + } + if (mp_cmp(out, mod) == MP_GT) { + return mp_sub(out, mod, out); + } + return err; +} + +bn_err bn_red_neg(const bn_t *one, const bn_t *mod, const red_t *red, bn_t *out) { + bn_err err; + if ((err = mp_neg(one, out)) != BN_OKAY) { + return err; + } + if (mp_cmp_d(out, 0) == MP_LT) { + return mp_add(out, mod, out); + } + return err; +} + +bn_err bn_red_mul(const bn_t *one, const bn_t *other, const bn_t *mod, const red_t *red, bn_t *out) { + bn_err err; + if ((err = mp_mul(one, other, out)) != BN_OKAY) { + return err; + } + return bn_red_reduce(mod, red, out); +} + +bn_err bn_red_sqr(const bn_t *one, const bn_t *mod, const red_t *red, bn_t *out) { + bn_err err; + if ((err = mp_sqr(one, out)) != BN_OKAY) { + return err; + } + return bn_red_reduce(mod, red, out); +} + +bn_err bn_red_inv(const bn_t *one, const bn_t *mod, const red_t *red, bn_t *out) { + bn_err err; + if ((err = mp_invmod(one, mod, out)) != BN_OKAY) { + return err; + } + #if REDUCTION == RED_MONTGOMERY + return mp_mulmod(out, &red->montgomery_renorm_sqr, mod, out); + #else + return err; + #endif +} + +bn_err bn_red_div(const bn_t *one, const bn_t *other, const bn_t *mod, const red_t *red, bn_t *out) { + bn_t inv; + bn_err err; + if ((err = mp_init(&inv)) != BN_OKAY) { + return err; + } + if ((err = mp_copy(other, &inv)) != BN_OKAY) { + goto out; + } + #if REDUCTION == RED_MONTGOMERY + if ((err = mp_montgomery_reduce(&inv, mod, red->montgomery_digit)) != BN_OKAY) { + goto out; + } + #endif + if ((err = mp_invmod(&inv, mod, &inv)) != BN_OKAY) { + goto out; + } + if ((err = mp_mulmod(one, &inv, mod, out)) != BN_OKAY) { + goto out; + } +out: + mp_clear(&inv); + return err; +} + +bn_err bn_red_pow(const bn_t *base, const bn_t *exp, const bn_t *mod, const red_t *red, bn_t *out) { + int blen = bn_bit_length(exp); + bn_t result; + bn_err err; + if ((err = bn_init(&result)) != BN_OKAY) { + return err; + } + if ((err = bn_copy(base, &result)) != BN_OKAY) { + bn_clear(&result); + return err; + } + for (int i = blen - 2; i > 0; --i) { + bn_red_sqr(&result, mod, red, &result); + if (bn_get_bit(exp, i)) { + bn_red_mul(&result, base, mod, red, &result); + } + } + return BN_OKAY; +} + +bn_err bn_red_reduce(const bn_t *mod, const red_t *red, bn_t *what) { + #if REDUCTION == RED_MONTGOMERY + return mp_montgomery_reduce(what, mod, red->montgomery_digit); + #elif REDUCTION == RED_BARRETT + return mp_reduce(what, mod, red->barrett); + #endif + return mp_mod(what, mod, what); +} + +void bn_red_clear(red_t *out) { + #if REDUCTION == RED_MONTGOMERY + bn_clear(&out->montgomery_renorm); + #elif REDUCTION == RED_BARRETT + bn_clear(&out->barret); + #endif +} + bn_err bn_lsh(const bn_t *one, int amount, bn_t *out) { return mp_mul_2d(one, amount, out); } |