=head1 NAME
-BN_mod_mul_reciprocal, BN_RECP_CTX_new, BN_RECP_CTX_init,
-BN_RECP_CTX_free, BN_RECP_CTX_set - Modular multiplication using
+BN_mod_mul_reciprocal, BN_div_recp, BN_RECP_CTX_new, BN_RECP_CTX_init,
+BN_RECP_CTX_free, BN_RECP_CTX_set - modular multiplication using
reciprocal
=head1 SYNOPSIS
#include <openssl/bn.h>
BN_RECP_CTX *BN_RECP_CTX_new(void);
- void BN_RECP_CTX_init(BN_RECP_CTX *recp);
void BN_RECP_CTX_free(BN_RECP_CTX *recp);
int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *m, BN_CTX *ctx);
+ int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *a, BN_RECP_CTX *recp,
+ BN_CTX *ctx);
+
int BN_mod_mul_reciprocal(BIGNUM *r, BIGNUM *a, BIGNUM *b,
BN_RECP_CTX *recp, BN_CTX *ctx);
=head1 DESCRIPTION
BN_mod_mul_reciprocal() can be used to perform an efficient
-BN_mod_mul(3) operation when the operation will be performed
+L<BN_mod_mul(3)|BN_mod_mul(3)> operation when the operation will be performed
repeatedly with the same modulus. It computes B<r>=(B<a>*B<b>)%B<m>
using B<recp>=1/B<m>, which is set as described below. B<ctx> is a
previously allocated B<BN_CTX> used for temporary variables.
BN_RECP_CTX_free() frees the components of the B<BN_RECP>, and, if it
was created by BN_RECP_CTX_new(), also the structure itself.
-BN_RECP_CTX_set() computes 1/B<m> and shifts it left by
-BN_num_bits(B<m>)+1 to make it an integer. The result and the
-number of bits it was shifted left are stored in B<recp>.
-
-The B<BN_RECP_CTX> structure is defined as follows:
+BN_RECP_CTX_set() stores B<m> in B<recp> and sets it up for computing
+1/B<m> and shifting it left by BN_num_bits(B<m>)+1 to make it an
+integer. The result and the number of bits it was shifted left will
+later be stored in B<recp>.
- typedef struct bn_recp_ctx_st
- {
- BIGNUM N; /* the divisor */
- BIGNUM Nr; /* the reciprocal */
- int num_bits;
- int shift;
- int flags;
- } BN_RECP_CTX;
+BN_div_recp() divides B<a> by B<m> using B<recp>. It places the quotient
+in B<dv> and the remainder in B<rem>.
-It cannot be shared between threads.
+The B<BN_RECP_CTX> structure cannot be shared between threads.
=head1 RETURN VALUES
BN_RECP_CTX_init() and BN_RECP_CTX_free() have no return values.
For the other functions, 1 is returned for success, 0 on error.
-The error codes can be obtained by ERR_get_error(3).
+The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
+
+=head1 REMOVED FUNCTIONALITY
+
+ void BN_RECP_CTX_init(BN_RECP_CTX *recp);
+
+BN_RECP_CTX_init() is no longer available as of OpenSSL 1.1.0. It was used to
+initialize an existing uninitialized B<BN_RECP_CTX>. Typically this would be
+done as follows:
+
+ BN_RECP_CTX ctx;
+ BN_RECP_CTX_init(&ctx);
+
+Applications should replace use of BN_RECP_CTX_init with BN_RECP_CTX_new
+instead:
+
+ BN_RECP_CTX *ctx;
+ ctx = BN_RECP_CTX_new();
+ if(!ctx) /* Handle error */
+ ...
+ BN_RECP_CTX_free(ctx);
=head1 SEE ALSO
-bn(3), err(3), BN_add(3), BN_CTX_new(3)
+L<bn(3)|bn(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<BN_add(3)|BN_add(3)>,
+L<BN_CTX_new(3)|BN_CTX_new(3)>
=head1 HISTORY
B<BN_RECP_CTX> was added in SSLeay 0.9.0. Before that, the function
BN_reciprocal() was used instead, and the BN_mod_mul_reciprocal()
-arguments werde different.
+arguments were different. BN_RECP_CTX_init was removed in OpenSSL 1.1.0
=cut