bn_mont.c fix [from HEAD].

This commit is contained in:
Andy Polyakov 2007-06-29 13:12:34 +00:00
parent 8dd8ce1dc3
commit a166e96d16

View File

@ -246,18 +246,12 @@ int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
rp=ret->d;
ap=&(r->d[ri]);
nrp=ap;
/* This 'if' denotes violation of 2*M<r^(n-1) boundary condition
* formulated by C.D.Walter in "Montgomery exponentiation needs
* no final subtractions." Incurred branch can disclose only
* information about modulus length, which is not really secret. */
if ((mont->N.d[ri-1]>>(BN_BITS2-2))!=0)
{
size_t m1,m2;
v=bn_sub_words(rp,ap,mont->N.d,ri);
/* this -----------------------^^ works even in al<ri case
v=bn_sub_words(rp,ap,np,ri);
/* this ----------------^^ works even in al<ri case
* thanks to zealous zeroing of top of the vector in the
* beginning. */