=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 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 and B and places the result in B (C). B may be the same B as B or B. BN_sub() subtracts B from B and places the result in B (C). BN_mul() multiplies B and B and places the result in B (C). B may be the same B as B or B. For multiplication by powers of 2, use L. BN_div() divides B by B and places the result in B and the remainder in B (C). Either of B and B may be NULL, in which case the respective value is not returned. For division by powers of 2, use BN_rshift(3). BN_sqr() takes the square of B and places the result in B (C). B and B may be the same B. This function is faster than BN_mul(r,a,a). BN_mod() find the remainder of B divided by B and places it in B (C). BN_mod_mul() multiplies B by B and finds the remainder when divided by B (C). B may be the same B as B or B. For a more efficient algorithm, see L; for repeated computations using the same modulus, see L. BN_exp() raises B to the B

-th power and places the result in B (C). This function is faster than repeated applications of BN_mul(). BN_mod_exp() computes B to the B

-th power modulo B (C). This function uses less time and space than BN_exp(). BN_gcd() computes the greatest common divisor of B and B and places the result in B. B may be the same B as B or B. For all functions, B is a previously allocated B used for temporary variables; see L. Unless noted otherwise, the result B 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). The error codes can be obtained by L. =head1 SEE ALSO L, L, L, L, L =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 argument to BN_mul() was added in SSLeay 0.9.1b. BN_exp() appeared in SSLeay 0.9.0. =cut