Mercurial > dropbear
view libtommath/bn_mp_prime_miller_rabin.c @ 1665:7c17995bcdfb
Improve address logging on early exit messages (#83)
Change 'Early exit' and 'Exit before auth' messages to include the IP
address & port as part of the message.
This allows log scanning utilities such as 'fail2ban' to obtain the
offending IP address as part of the failure event instead of extracting
the PID from the message and then scanning the log again for match
'child connection from' messages
Signed-off-by: Kevin Darbyshire-Bryant <[email protected]>
author | Kevin Darbyshire-Bryant <6500011+ldir-EDB0@users.noreply.github.com> |
---|---|
date | Wed, 18 Mar 2020 15:28:56 +0000 |
parents | f52919ffd3b1 |
children | 1051e4eea25a |
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line source
#include "tommath_private.h" #ifdef BN_MP_PRIME_MILLER_RABIN_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 */ /* Miller-Rabin test of "a" to the base of "b" as described in * HAC pp. 139 Algorithm 4.24 * * Sets result to 0 if definitely composite or 1 if probably prime. * Randomly the chance of error is no more than 1/4 and often * very much lower. */ int mp_prime_miller_rabin(const mp_int *a, const mp_int *b, int *result) { mp_int n1, y, r; int s, j, err; /* default */ *result = MP_NO; /* ensure b > 1 */ if (mp_cmp_d(b, 1uL) != MP_GT) { return MP_VAL; } /* get n1 = a - 1 */ if ((err = mp_init_copy(&n1, a)) != MP_OKAY) { return err; } if ((err = mp_sub_d(&n1, 1uL, &n1)) != MP_OKAY) { goto LBL_N1; } /* set 2**s * r = n1 */ if ((err = mp_init_copy(&r, &n1)) != MP_OKAY) { goto LBL_N1; } /* count the number of least significant bits * which are zero */ s = mp_cnt_lsb(&r); /* now divide n - 1 by 2**s */ if ((err = mp_div_2d(&r, s, &r, NULL)) != MP_OKAY) { goto LBL_R; } /* compute y = b**r mod a */ if ((err = mp_init(&y)) != MP_OKAY) { goto LBL_R; } if ((err = mp_exptmod(b, &r, a, &y)) != MP_OKAY) { goto LBL_Y; } /* if y != 1 and y != n1 do */ if ((mp_cmp_d(&y, 1uL) != MP_EQ) && (mp_cmp(&y, &n1) != MP_EQ)) { j = 1; /* while j <= s-1 and y != n1 */ while ((j <= (s - 1)) && (mp_cmp(&y, &n1) != MP_EQ)) { if ((err = mp_sqrmod(&y, a, &y)) != MP_OKAY) { goto LBL_Y; } /* if y == 1 then composite */ if (mp_cmp_d(&y, 1uL) == MP_EQ) { goto LBL_Y; } ++j; } /* if y != n1 then composite */ if (mp_cmp(&y, &n1) != MP_EQ) { goto LBL_Y; } } /* probably prime now */ *result = MP_YES; LBL_Y: mp_clear(&y); LBL_R: mp_clear(&r); LBL_N1: mp_clear(&n1); return err; } #endif /* ref: HEAD -> master, tag: v1.1.0 */ /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ /* commit time: 2019-01-28 20:32:32 +0100 */