Mercurial > dropbear
view libtommath/bn_mp_expt_d.c @ 1156:a8f4dade70e5
avoid getpass when not used
some systems (like android's bionic) do not provide getpass. you can
disable ENABLE_CLI_PASSWORD_AUTH & ENABLE_CLI_INTERACT_AUTH to avoid
its use (and rely on pubkey auth), but the link still fails because
the support file calls getpass. do not define this func if both of
those auth methods are not used.
author | Mike Frysinger <vapier@gentoo.org> |
---|---|
date | Wed, 21 Oct 2015 22:39:55 +0800 |
parents | 5ff8218bcee9 |
children | 60fc6476e044 |
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#include <tommath.h> #ifdef BN_MP_EXPT_D_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. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, [email protected], http://math.libtomcrypt.com */ /* calculate c = a**b using a square-multiply algorithm */ int mp_expt_d (mp_int * a, mp_digit b, mp_int * c) { int res, x; mp_int g; if ((res = mp_init_copy (&g, a)) != MP_OKAY) { return res; } /* set initial result */ mp_set (c, 1); for (x = 0; x < (int) DIGIT_BIT; x++) { /* square */ if ((res = mp_sqr (c, c)) != MP_OKAY) { mp_clear (&g); return res; } /* if the bit is set multiply */ if ((b & (mp_digit) (((mp_digit)1) << (DIGIT_BIT - 1))) != 0) { if ((res = mp_mul (c, &g, c)) != MP_OKAY) { mp_clear (&g); return res; } } /* shift to next bit */ b <<= 1; } mp_clear (&g); return MP_OKAY; } #endif /* $Source: /cvs/libtom/libtommath/bn_mp_expt_d.c,v $ */ /* $Revision: 1.3 $ */ /* $Date: 2006/03/31 14:18:44 $ */