diff options
author | Ulf Möller <ulf@openssl.org> | 2000-01-23 22:06:24 +0000 |
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committer | Ulf Möller <ulf@openssl.org> | 2000-01-23 22:06:24 +0000 |
commit | dd8dec69b825c9fdafc26a200961702d850496b5 (patch) | |
tree | b7d7ca7365271c822226e1ddc6a4fd68c72273ad /doc/crypto/BN_add.pod | |
parent | ce052b6c3b18d4ab5f74990d82d09827a6014823 (diff) |
Document the BN library.
Diffstat (limited to 'doc/crypto/BN_add.pod')
-rw-r--r-- | doc/crypto/BN_add.pod | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/doc/crypto/BN_add.pod b/doc/crypto/BN_add.pod new file mode 100644 index 0000000000..b2bfe0c2e6 --- /dev/null +++ b/doc/crypto/BN_add.pod @@ -0,0 +1,95 @@ +=pod + +=head1 NAME + +BN_add, BN_sub, BN_mul, BN_div, BN_sqr, BN_mod, BN_mod_mul, BN_exp, +BN_mod_exp, BN_gcd - Arithmetic operations on BIGNUMs + +=head1 SYNOPSIS + + #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_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *a, const BIGNUM *d, + BN_CTX *ctx); + + int BN_sqr(BIGNUM *r, BIGNUM *a, BN_CTX *ctx); + + int BN_mod(BIGNUM *rem, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx); + + int BN_mod_mul(BIGNUM *ret, BIGNUM *a, BIGNUM *b, const BIGNUM *m, + 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); + +=head1 DESCRIPTION + +BN_add() adds B<a> and B<b> and places the result in B<r> (C<r=a+b>). +B<r> may be the same B<BIGNUM> as B<a> or B<b>. + +BN_sub() substracts B<b> from B<a> and places the result in B<r> (C<r=a-b>). + +BN_mul() multiplies B<a> and B<b> and places the result in B<r> (C<r=a*b>). + +BN_div() divides B<a> by B<d> and places the result in B<dv> and the +remainder in B<rem> (C<dv=a/d, rem=a%d>). Either of B<dv> and B<rem> may +be NULL, in which case the respective value is not returned. + +BN_sqr() takes the square of B<a> and places the result in B<r> +(C<r=a^2>). B<r> and B<a> may be the same B<BIGNUM>. +This function is faster than BN_mul(r,a,a). + +BN_mod() find the remainder of B<a> divided by B<m> and places it in +B<rem> (C<rem=a%m>). + +BN_mod_mul() multiplies B<a> by B<b> and finds the remainder when +divided by B<m> (C<r=(a*b)%m>). B<r> may be the same B<BIGNUM> as B<a> +or B<b>. For a more efficient algorithm, see +L<BN_mod_mul_montgomery(3)>; for repeated computations using the same +modulus, see L<BN_mod_mul_reciprocal(3)>. + +BN_exp() raises B<a> to the B<p>-th power and places the result in B<r> +(C<r=a^p>). This function is faster than repeated applications of +BN_mul(). + +BN_mod_exp() computes B<a> to the B<p>-th power modulo B<m> (C<r=a^p % +m>). This function uses less time and space than BN_exp(). + +BN_gcd() computes the greatest common divisor of B<a> and B<b> and +places the result in B<r>. B<r> may be the same B<BIGNUM> as B<a> or +B<b>. + +For all functions, B<ctx> is a previously allocated B<BN_CTX> used for +temporary variables; see L<BN_CTX_new(3)>. + +Unless noted otherwise, the result B<BIGNUM> must be different from +the arguments. + +=head1 RETURN VALUES + +For all 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;>). +The error codes can be obtained by ERR_get_error(3). + +=head1 SEE ALSO + +bn(3), err(3), BN_CTX_new(3), BN_add_word(3), BN_set_bit(3) + +=head1 HISTORY + +BN_add(), BN_sub(), BN_div(), BN_sqr(), BN_mod(), BN_mod_mul(), +BN_mod_exp() and BN_gcd() are available in all versions of SSLeay and +OpenSSL. The B<ctx> argument to BN_mul() was added in SSLeay +0.9.1b. BN_exp() appeared in SSLeay 0.9.0. + +=cut |