Mercurial > dropbear
view libtommath/bn_fast_mp_invmod.c @ 1672:3a97f14c0235
Add Chacha20-Poly1305, AES128-GCM and AES256-GCM support (#93)
* Add Chacha20-Poly1305 authenticated encryption
* Add general AEAD approach.
* Add [email protected] algo using LibTomCrypt chacha and
poly1305 routines.
Chacha20-Poly1305 is generally faster than AES256 on CPU w/o dedicated
AES instructions, having the same key size.
Compiling in will add ~5,5kB to binary size on x86-64.
function old new delta
chacha_crypt - 1397 +1397
_poly1305_block - 608 +608
poly1305_done - 595 +595
dropbear_chachapoly_crypt - 457 +457
.rodata 26976 27392 +416
poly1305_process - 290 +290
poly1305_init - 221 +221
chacha_setup - 218 +218
encrypt_packet 1068 1270 +202
dropbear_chachapoly_getlength - 147 +147
decrypt_packet 756 897 +141
chacha_ivctr64 - 137 +137
read_packet 543 637 +94
dropbear_chachapoly_start - 94 +94
read_kex_algos 792 880 +88
chacha_keystream - 69 +69
dropbear_mode_chachapoly - 48 +48
sshciphers 280 320 +40
dropbear_mode_none 24 48 +24
dropbear_mode_ctr 24 48 +24
dropbear_mode_cbc 24 48 +24
dropbear_chachapoly_mac - 24 +24
dropbear_chachapoly - 24 +24
gen_new_keys 848 854 +6
------------------------------------------------------------------------------
(add/remove: 14/0 grow/shrink: 10/0 up/down: 5388/0) Total: 5388 bytes
* Add AES128-GCM and AES256-GCM authenticated encryption
* Add general AES-GCM mode.
* Add [email protected] and [email protected] algo using
LibTomCrypt gcm routines.
AES-GCM is combination of AES CTR mode and GHASH, slower than AES-CTR on
CPU w/o dedicated AES/GHASH instructions therefore disabled by default.
Compiling in will add ~6kB to binary size on x86-64.
function old new delta
gcm_process - 1060 +1060
.rodata 26976 27808 +832
gcm_gf_mult - 820 +820
gcm_add_aad - 660 +660
gcm_shift_table - 512 +512
gcm_done - 471 +471
gcm_add_iv - 384 +384
gcm_init - 347 +347
dropbear_gcm_crypt - 309 +309
encrypt_packet 1068 1270 +202
decrypt_packet 756 897 +141
gcm_reset - 118 +118
read_packet 543 637 +94
read_kex_algos 792 880 +88
sshciphers 280 360 +80
gcm_mult_h - 80 +80
dropbear_gcm_start - 62 +62
dropbear_mode_gcm - 48 +48
dropbear_mode_none 24 48 +24
dropbear_mode_ctr 24 48 +24
dropbear_mode_cbc 24 48 +24
dropbear_ghash - 24 +24
dropbear_gcm_getlength - 24 +24
gen_new_keys 848 854 +6
------------------------------------------------------------------------------
(add/remove: 14/0 grow/shrink: 10/0 up/down: 6434/0) Total: 6434 bytes
author | Vladislav Grishenko <themiron@users.noreply.github.com> |
---|---|
date | Mon, 25 May 2020 20:50:25 +0500 |
parents | f52919ffd3b1 |
children |
line wrap: on
line source
#include "tommath_private.h" #ifdef BN_FAST_MP_INVMOD_C /* LibTomMath, multiple-precision integer library -- Tom St Denis * * LibTomMath is a library that provides multiple-precision * integer arithmetic as well as number theoretic functionality. * * The library was designed directly after the MPI library by * Michael Fromberger but has been written from scratch with * additional optimizations in place. * * SPDX-License-Identifier: Unlicense */ /* computes the modular inverse via binary extended euclidean algorithm, * that is c = 1/a mod b * * Based on slow invmod except this is optimized for the case where b is * odd as per HAC Note 14.64 on pp. 610 */ int fast_mp_invmod(const mp_int *a, const mp_int *b, mp_int *c) { mp_int x, y, u, v, B, D; int res, neg; /* 2. [modified] b must be odd */ if (mp_iseven(b) == MP_YES) { return MP_VAL; } /* init all our temps */ if ((res = mp_init_multi(&x, &y, &u, &v, &B, &D, NULL)) != MP_OKAY) { return res; } /* x == modulus, y == value to invert */ if ((res = mp_copy(b, &x)) != MP_OKAY) { goto LBL_ERR; } /* we need y = |a| */ if ((res = mp_mod(a, b, &y)) != MP_OKAY) { goto LBL_ERR; } /* if one of x,y is zero return an error! */ if ((mp_iszero(&x) == MP_YES) || (mp_iszero(&y) == MP_YES)) { res = MP_VAL; goto LBL_ERR; } /* 3. u=x, v=y, A=1, B=0, C=0,D=1 */ if ((res = mp_copy(&x, &u)) != MP_OKAY) { goto LBL_ERR; } if ((res = mp_copy(&y, &v)) != MP_OKAY) { goto LBL_ERR; } mp_set(&D, 1uL); top: /* 4. while u is even do */ while (mp_iseven(&u) == MP_YES) { /* 4.1 u = u/2 */ if ((res = mp_div_2(&u, &u)) != MP_OKAY) { goto LBL_ERR; } /* 4.2 if B is odd then */ if (mp_isodd(&B) == MP_YES) { if ((res = mp_sub(&B, &x, &B)) != MP_OKAY) { goto LBL_ERR; } } /* B = B/2 */ if ((res = mp_div_2(&B, &B)) != MP_OKAY) { goto LBL_ERR; } } /* 5. while v is even do */ while (mp_iseven(&v) == MP_YES) { /* 5.1 v = v/2 */ if ((res = mp_div_2(&v, &v)) != MP_OKAY) { goto LBL_ERR; } /* 5.2 if D is odd then */ if (mp_isodd(&D) == MP_YES) { /* D = (D-x)/2 */ if ((res = mp_sub(&D, &x, &D)) != MP_OKAY) { goto LBL_ERR; } } /* D = D/2 */ if ((res = mp_div_2(&D, &D)) != MP_OKAY) { goto LBL_ERR; } } /* 6. if u >= v then */ if (mp_cmp(&u, &v) != MP_LT) { /* u = u - v, B = B - D */ if ((res = mp_sub(&u, &v, &u)) != MP_OKAY) { goto LBL_ERR; } if ((res = mp_sub(&B, &D, &B)) != MP_OKAY) { goto LBL_ERR; } } else { /* v - v - u, D = D - B */ if ((res = mp_sub(&v, &u, &v)) != MP_OKAY) { goto LBL_ERR; } if ((res = mp_sub(&D, &B, &D)) != MP_OKAY) { goto LBL_ERR; } } /* if not zero goto step 4 */ if (mp_iszero(&u) == MP_NO) { goto top; } /* now a = C, b = D, gcd == g*v */ /* if v != 1 then there is no inverse */ if (mp_cmp_d(&v, 1uL) != MP_EQ) { res = MP_VAL; goto LBL_ERR; } /* b is now the inverse */ neg = a->sign; while (D.sign == MP_NEG) { if ((res = mp_add(&D, b, &D)) != MP_OKAY) { goto LBL_ERR; } } /* too big */ while (mp_cmp_mag(&D, b) != MP_LT) { if ((res = mp_sub(&D, b, &D)) != MP_OKAY) { goto LBL_ERR; } } mp_exch(&D, c); c->sign = neg; res = MP_OKAY; LBL_ERR: mp_clear_multi(&x, &y, &u, &v, &B, &D, NULL); return res; } #endif /* ref: HEAD -> master, tag: v1.1.0 */ /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ /* commit time: 2019-01-28 20:32:32 +0100 */