OpenGrok

$NetBSD: BN_mod_mul_montgomery.3,v 1.1.1.2 2023/04/18 14:19:13 christos Exp $

Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35)

Standard preamble:
========================================================================
..

..

.. Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is >0, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================

Title "BN_mod_mul_montgomery 3" For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
.nh BN_mod_mul_montgomery, BN_MONT_CTX_new, BN_MONT_CTX_free, BN_MONT_CTX_set, BN_MONT_CTX_copy, BN_from_montgomery, BN_to_montgomery - Montgomery multiplication libcrypto, -lcrypto Header "SYNOPSIS" .Vb 1 #include <openssl/bn.h> \& BN_MONT_CTX *BN_MONT_CTX_new(void); void BN_MONT_CTX_free(BN_MONT_CTX *mont); \& int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *m, BN_CTX *ctx); BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from); \& int BN_mod_mul_montgomery(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_MONT_CTX *mont, BN_CTX *ctx); \& int BN_from_montgomery(BIGNUM *r, BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx); \& int BN_to_montgomery(BIGNUM *r, BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx); .Ve Header "DESCRIPTION" These functions implement Montgomery multiplication. They are used automatically when BN_mod_exp\|(3) is called with suitable input, but they may be useful when several operations are to be performed using the same modulus.

\fBBN_MONT_CTX_new() allocates and initializes a \s-1BN_MONT_CTX\s0 structure.

\fBBN_MONT_CTX_set() sets up the mont structure from the modulus m by precomputing its inverse and a value R.

\fBBN_MONT_CTX_copy() copies the \s-1BN_MONT_CTX\s0 from to to.

\fBBN_MONT_CTX_free() frees the components of the \s-1BN_MONT_CTX\s0, and, if it was created by BN_MONT_CTX_new(), also the structure itself. If mont is \s-1NULL,\s0 nothing is done.

\fBBN_mod_mul_montgomery() computes Mont(a,b):=a*b*R^-1 and places the result in r.

\fBBN_from_montgomery() performs the Montgomery reduction r = a*R^-1.

\fBBN_to_montgomery() computes Mont(a,R^2), i.e. a*R. Note that a must be nonnegative and smaller than the modulus.

For all functions, ctx is a previously allocated \s-1BN_CTX\s0 used for temporary variables.

Header "RETURN VALUES" \fBBN_MONT_CTX_new() returns the newly allocated \s-1BN_MONT_CTX\s0, and \s-1NULL\s0 on error.

\fBBN_MONT_CTX_free() has no return value.

For the other functions, 1 is returned for success, 0 on error. The error codes can be obtained by ERR_get_error\|(3).

Header "WARNINGS" The inputs must be reduced modulo m, otherwise the result will be outside the expected range. Header "SEE ALSO" \fBERR_get_error\|(3), BN_add\|(3), \fBBN_CTX_new\|(3) Header "HISTORY" \fBBN_MONT_CTX_init() was removed in OpenSSL 1.1.0 Header "COPYRIGHT" Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.

Indexes created Fri Apr 24 00:22:58 UTC 2026