Mercurial > dropbear
view libtommath/bn_mp_mul.c @ 1638:315fcba6960e
dropbearconvert: keyimport.c: fix BER encoding of secp521r1 keys (#69)
keysizes >= 128 octets will be encoded with a 3 byte header
which must be accounted by the optional-header
Reproduce:
master:~/build/dropbear$ ./dropbearkey -t ecdsa -s 521 -f K
Generating 521 bit ecdsa key, this may take a while...
master:~/build/dropbear$ ./dropbearconvert d o K L
Key is a ecdsa-sha2-nistp521 key
Wrote key to 'L'
master:~/build/dropbear$ openssl ec < L
read EC key
unable to load Key
139769806448384:error:0D07209B:asn1 encoding routines:ASN1_get_object:too long:crypto/asn1/asn1_lib.c:91:
author | Christian Hohnstädt <christian@hohnstaedt.de> |
---|---|
date | Wed, 20 Mar 2019 16:42:47 +0100 |
parents | 8bba51a55704 |
children | f52919ffd3b1 |
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line source
#include <tommath_private.h> #ifdef BN_MP_MUL_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://libtom.org */ /* high level multiplication (handles sign) */ int mp_mul (mp_int * a, mp_int * b, mp_int * c) { int res, neg; neg = (a->sign == b->sign) ? MP_ZPOS : MP_NEG; /* use Toom-Cook? */ #ifdef BN_MP_TOOM_MUL_C if (MIN (a->used, b->used) >= TOOM_MUL_CUTOFF) { res = mp_toom_mul(a, b, c); } else #endif #ifdef BN_MP_KARATSUBA_MUL_C /* use Karatsuba? */ if (MIN (a->used, b->used) >= KARATSUBA_MUL_CUTOFF) { res = mp_karatsuba_mul (a, b, c); } else #endif { /* can we use the fast multiplier? * * The fast multiplier can be used if the output will * have less than MP_WARRAY digits and the number of * digits won't affect carry propagation */ int digs = a->used + b->used + 1; #ifdef BN_FAST_S_MP_MUL_DIGS_C if ((digs < MP_WARRAY) && (MIN(a->used, b->used) <= (1 << ((CHAR_BIT * sizeof(mp_word)) - (2 * DIGIT_BIT))))) { res = fast_s_mp_mul_digs (a, b, c, digs); } else #endif { #ifdef BN_S_MP_MUL_DIGS_C res = s_mp_mul (a, b, c); /* uses s_mp_mul_digs */ #else res = MP_VAL; #endif } } c->sign = (c->used > 0) ? neg : MP_ZPOS; return res; } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */