view libtommath/bn_mp_prime_rabin_miller_trials.c @ 1659:d32bcb5c557d

Add Ed25519 support (#91) * Add support for Ed25519 as a public key type Ed25519 is a elliptic curve signature scheme that offers better security than ECDSA and DSA and good performance. It may be used for both user and host keys. OpenSSH key import and fuzzer are not supported yet. Initially inspired by Peter Szabo. * Add curve25519 and ed25519 fuzzers * Add import and export of Ed25519 keys
author Vladislav Grishenko <themiron@users.noreply.github.com>
date Wed, 11 Mar 2020 21:09:45 +0500
parents a36e545fb43d
children 1051e4eea25a
line wrap: on
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#include "tommath_private.h"
#ifdef BN_MP_PRIME_RABIN_MILLER_TRIALS_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
 */


static const struct {
   int k, t;
} sizes[] = {
   {    80,    -1 }, /* Use deterministic algorithm for size <= 80 bits */
   {    81,    39 },
   {    96,    37 },
   {   128,    32 },
   {   160,    27 },
   {   192,    21 },
   {   256,    16 },
   {   384,    10 },
   {   512,     7 },
   {   640,     6 },
   {   768,     5 },
   {   896,     4 },
   {  1024,     4 },
   {  2048,     2 }  /* For bigger keysizes use always at least 2 Rounds */
};

/* returns # of RM trials required for a given bit size and max. error of 2^(-96)*/
int mp_prime_rabin_miller_trials(int size)
{
   int x;

   for (x = 0; x < (int)(sizeof(sizes)/(sizeof(sizes[0]))); x++) {
      if (sizes[x].k == size) {
         return sizes[x].t;
      } else if (sizes[x].k > size) {
         return (x == 0) ? sizes[0].t : sizes[x - 1].t;
      }
   }
   return sizes[x-1].t;
}


#endif

/* ref:         HEAD -> master, tag: v1.1.0 */
/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
/* commit time: 2019-01-28 20:32:32 +0100 */