view libtommath/bn_mp_clamp.c @ 1907:3e0aacf0a4f3

Fix ed25519 dropbear to openssh conversion This introduces buf_put_ed25519_priv_ossh and buf_get_ed25519_priv_ossh to handle OpenSSH internal private key format. Previously writing OpenSSH format keys didn't write the private part correctly.
author Matt Johnston <matt@ucc.asn.au>
date Tue, 29 Mar 2022 16:46:06 +0800
parents 1051e4eea25a
children
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#include "tommath_private.h"
#ifdef BN_MP_CLAMP_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */

/* trim unused digits
 *
 * This is used to ensure that leading zero digits are
 * trimed and the leading "used" digit will be non-zero
 * Typically very fast.  Also fixes the sign if there
 * are no more leading digits
 */
void mp_clamp(mp_int *a)
{
   /* decrease used while the most significant digit is
    * zero.
    */
   while ((a->used > 0) && (a->dp[a->used - 1] == 0u)) {
      --(a->used);
   }

   /* reset the sign flag if used == 0 */
   if (a->used == 0) {
      a->sign = MP_ZPOS;
   }
}
#endif