xref: /freebsd/secure/lib/libcrypto/man/man3/BN_add.3 (revision 924226fba12cc9a228c73b956e1b7fa24c60b055)
Automatically generated by Pod::Man 4.14 (Pod::Simple 3.40)

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_ADD 3"
BN_ADD 3 "2022-06-21" "1.1.1p" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
"NAME"
BN_add, BN_sub, BN_mul, BN_sqr, BN_div, BN_mod, BN_nnmod, BN_mod_add, BN_mod_sub, BN_mod_mul, BN_mod_sqr, BN_mod_sqrt, BN_exp, BN_mod_exp, BN_gcd - arithmetic operations on BIGNUMs
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/bn.h> \& int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b); \& int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b); \& int BN_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_CTX *ctx); \& int BN_sqr(BIGNUM *r, BIGNUM *a, BN_CTX *ctx); \& int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *a, const BIGNUM *d, BN_CTX *ctx); \& int BN_mod(BIGNUM *rem, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx); \& int BN_nnmod(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx); \& int BN_mod_add(BIGNUM *r, BIGNUM *a, BIGNUM *b, const BIGNUM *m, BN_CTX *ctx); \& int BN_mod_sub(BIGNUM *r, BIGNUM *a, BIGNUM *b, const BIGNUM *m, BN_CTX *ctx); \& int BN_mod_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b, const BIGNUM *m, BN_CTX *ctx); \& int BN_mod_sqr(BIGNUM *r, BIGNUM *a, const BIGNUM *m, BN_CTX *ctx); \& BIGNUM *BN_mod_sqrt(BIGNUM *in, BIGNUM *a, const BIGNUM *p, BN_CTX *ctx); \& int BN_exp(BIGNUM *r, BIGNUM *a, BIGNUM *p, BN_CTX *ctx); \& int BN_mod_exp(BIGNUM *r, BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx); \& int BN_gcd(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_CTX *ctx); .Ve
"DESCRIPTION"
Header "DESCRIPTION" \fBBN_add() adds a and b and places the result in r (\*(C`r=a+b\*(C'). \fIr may be the same \s-1BIGNUM\s0 as a or b.

\fBBN_sub() subtracts b from a and places the result in r (\*(C`r=a-b\*(C'). \fIr may be the same \s-1BIGNUM\s0 as a or b.

\fBBN_mul() multiplies a and b and places the result in r (\*(C`r=a*b\*(C'). \fIr may be the same \s-1BIGNUM\s0 as a or b. For multiplication by powers of 2, use BN_lshift\|(3).

\fBBN_sqr() takes the square of a and places the result in r (\*(C`r=a^2\*(C'). r and a may be the same \s-1BIGNUM\s0. This function is faster than BN_mul(r,a,a).

\fBBN_div() divides a by d and places the result in dv and the remainder in rem (\*(C`dv=a/d, rem=a%d\*(C'). Either of dv and rem may be \s-1NULL\s0, in which case the respective value is not returned. The result is rounded towards zero; thus if a is negative, the remainder will be zero or negative. For division by powers of 2, use BN_rshift\|(3).

\fBBN_mod() corresponds to BN_div() with dv set to \s-1NULL\s0.

\fBBN_nnmod() reduces a modulo m and places the nonnegative remainder in r.

\fBBN_mod_add() adds a to b modulo m and places the nonnegative result in r.

\fBBN_mod_sub() subtracts b from a modulo m and places the nonnegative result in r.

\fBBN_mod_mul() multiplies a by b and finds the nonnegative remainder respective to modulus m (\*(C`r=(a*b) mod m\*(C'). r may be the same \s-1BIGNUM\s0 as a or b. For more efficient algorithms for repeated computations using the same modulus, see \fBBN_mod_mul_montgomery\|(3) and \fBBN_mod_mul_reciprocal\|(3).

\fBBN_mod_sqr() takes the square of a modulo m and places the result in r.

\fBBN_mod_sqrt() returns the modular square root of a such that \f(CW\*(C`in^2 = a (mod p)\*(C'. The modulus p must be a prime, otherwise an error or an incorrect \*(L"result\*(R" will be returned. The result is stored into in which can be \s-1NULL.\s0 The result will be newly allocated in that case.

\fBBN_exp() raises a to the p-th power and places the result in r (\*(C`r=a^p\*(C'). This function is faster than repeated applications of \fBBN_mul().

\fBBN_mod_exp() computes a to the p-th power modulo m (\*(C`r=a^p % m\*(C'). This function uses less time and space than BN_exp(). Do not call this function when m is even and any of the parameters have the \fB\s-1BN_FLG_CONSTTIME\s0 flag set.

\fBBN_gcd() computes the greatest common divisor of a and b and places the result in r. r may be the same \s-1BIGNUM\s0 as a or \fIb.

For all functions, ctx is a previously allocated \s-1BN_CTX\s0 used for temporary variables; see BN_CTX_new\|(3).

Unless noted otherwise, the result \s-1BIGNUM\s0 must be different from the arguments.

"RETURN VALUES"
Header "RETURN VALUES" The BN_mod_sqrt() returns the result (possibly incorrect if p is not a prime), or \s-1NULL.\s0

For all remaining functions, 1 is returned for success, 0 on error. The return value should always be checked (e.g., \*(C`if (!BN_add(r,a,b)) goto err;\*(C'). The error codes can be obtained by ERR_get_error\|(3).

"SEE ALSO"
Header "SEE ALSO" \fBERR_get_error\|(3), BN_CTX_new\|(3), \fBBN_add_word\|(3), BN_set_bit\|(3)
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2000-2022 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>.