Commit 3a070e25 authored by Matt Caswell's avatar Matt Caswell
Browse files

Clarify BN_mod_exp docs



Specifically this is not supported with an even modulus and
BN_FLG_CONSTTIME.

Fixes #5082

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6137)
parent ecd4b8fe
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+3 −1
Original line number Diff line number Diff line
@@ -92,7 +92,9 @@ BN_exp() raises I<a> to the I<p>-th power and places the result in I<r>
BN_mul().

BN_mod_exp() computes I<a> to the I<p>-th power modulo I<m> (C<r=a^p %
m>). This function uses less time and space than BN_exp().
m>). This function uses less time and space than BN_exp(). Do not call this
function when B<m> is even and any of the parameters have the
B<BN_FLG_CONSTTIME> flag set.

BN_gcd() computes the greatest common divisor of I<a> and I<b> and
places the result in I<r>. I<r> may be the same B<BIGNUM> as I<a> or