# bn_is_one(3) [osx man page]

BN_cmp(3)							      OpenSSL								 BN_cmp(3)

NAME
BN_cmp, BN_ucmp, BN_is_zero, BN_is_one, BN_is_word, BN_is_odd - BIGNUM comparison and test functions SYNOPSIS
#include <openssl/bn.h> int BN_cmp(BIGNUM *a, BIGNUM *b); int BN_ucmp(BIGNUM *a, BIGNUM *b); int BN_is_zero(BIGNUM *a); int BN_is_one(BIGNUM *a); int BN_is_word(BIGNUM *a, BN_ULONG w); int BN_is_odd(BIGNUM *a); DESCRIPTION
BN_cmp() compares the numbers a and b. BN_ucmp() compares their absolute values. BN_is_zero(), BN_is_one() and BN_is_word() test if a equals 0, 1, or w respectively. BN_is_odd() tests if a is odd. BN_is_zero(), BN_is_one(), BN_is_word() and BN_is_odd() are macros. RETURN VALUES
BN_cmp() returns -1 if a < b, 0 if a == b and 1 if a > b. BN_ucmp() is the same using the absolute values of a and b. BN_is_zero(), BN_is_one() BN_is_word() and BN_is_odd() return 1 if the condition is true, 0 otherwise. SEE ALSO
bn(3) HISTORY
BN_cmp(), BN_ucmp(), BN_is_zero(), BN_is_one() and BN_is_word() are available in all versions of SSLeay and OpenSSL. BN_is_odd() was added in SSLeay 0.8. 0.9.8 2009-04-03 BN_cmp(3)

## Check Out this Related Man Page

bn(3)								      OpenSSL								     bn(3)

NAME
bn - multiprecision integer arithmetics SYNOPSIS
#include <openssl/bn.h> BIGNUM *BN_new(void); void BN_free(BIGNUM *a); void BN_init(BIGNUM *); void BN_clear(BIGNUM *a); void BN_clear_free(BIGNUM *a); BN_CTX *BN_CTX_new(void); void BN_CTX_init(BN_CTX *c); void BN_CTX_free(BN_CTX *c); BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b); BIGNUM *BN_dup(const BIGNUM *a); BIGNUM *BN_swap(BIGNUM *a, BIGNUM *b); int BN_num_bytes(const BIGNUM *a); int BN_num_bits(const BIGNUM *a); int BN_num_bits_word(BN_ULONG w); 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 *rem, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx); int BN_mod_add(BIGNUM *ret, BIGNUM *a, BIGNUM *b, const BIGNUM *m, BN_CTX *ctx); int BN_mod_sub(BIGNUM *ret, BIGNUM *a, BIGNUM *b, const BIGNUM *m, BN_CTX *ctx); int BN_mod_mul(BIGNUM *ret, BIGNUM *a, BIGNUM *b, const BIGNUM *m, BN_CTX *ctx); int BN_mod_sqr(BIGNUM *ret, BIGNUM *a, 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); int BN_add_word(BIGNUM *a, BN_ULONG w); int BN_sub_word(BIGNUM *a, BN_ULONG w); int BN_mul_word(BIGNUM *a, BN_ULONG w); BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w); BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w); int BN_cmp(BIGNUM *a, BIGNUM *b); int BN_ucmp(BIGNUM *a, BIGNUM *b); int BN_is_zero(BIGNUM *a); int BN_is_one(BIGNUM *a); int BN_is_word(BIGNUM *a, BN_ULONG w); int BN_is_odd(BIGNUM *a); int BN_zero(BIGNUM *a); int BN_one(BIGNUM *a); const BIGNUM *BN_value_one(void); int BN_set_word(BIGNUM *a, unsigned long w); unsigned long BN_get_word(BIGNUM *a); int BN_rand(BIGNUM *rnd, int bits, int top, int bottom); int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom); int BN_rand_range(BIGNUM *rnd, BIGNUM *range); int BN_pseudo_rand_range(BIGNUM *rnd, BIGNUM *range); BIGNUM *BN_generate_prime(BIGNUM *ret, int bits,int safe, BIGNUM *add, BIGNUM *rem, void (*callback)(int, int, void *), void *cb_arg); int BN_is_prime(const BIGNUM *p, int nchecks, void (*callback)(int, int, void *), BN_CTX *ctx, void *cb_arg); int BN_set_bit(BIGNUM *a, int n); int BN_clear_bit(BIGNUM *a, int n); int BN_is_bit_set(const BIGNUM *a, int n); int BN_mask_bits(BIGNUM *a, int n); int BN_lshift(BIGNUM *r, const BIGNUM *a, int n); int BN_lshift1(BIGNUM *r, BIGNUM *a); int BN_rshift(BIGNUM *r, BIGNUM *a, int n); int BN_rshift1(BIGNUM *r, BIGNUM *a); int BN_bn2bin(const BIGNUM *a, unsigned char *to); BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret); char *BN_bn2hex(const BIGNUM *a); char *BN_bn2dec(const BIGNUM *a); int BN_hex2bn(BIGNUM **a, const char *str); int BN_dec2bn(BIGNUM **a, const char *str); int BN_print(BIO *fp, const BIGNUM *a); int BN_print_fp(FILE *fp, const BIGNUM *a); int BN_bn2mpi(const BIGNUM *a, unsigned char *to); BIGNUM *BN_mpi2bn(unsigned char *s, int len, BIGNUM *ret); BIGNUM *BN_mod_inverse(BIGNUM *r, BIGNUM *a, const BIGNUM *n, BN_CTX *ctx); 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_mod_mul_reciprocal(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_RECP_CTX *recp, BN_CTX *ctx); BN_MONT_CTX *BN_MONT_CTX_new(void); void BN_MONT_CTX_init(BN_MONT_CTX *ctx); 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); DESCRIPTION
This library performs arithmetic operations on integers of arbitrary size. It was written for use in public key cryptography, such as RSA and Diffie-Hellman. It uses dynamic memory allocation for storing its data structures. That means that there is no limit on the size of the numbers manipu- lated by these functions, but return values must always be checked in case a memory allocation error has occurred. The basic object in this library is a BIGNUM. It is used to hold a single large integer. This type should be considered opaque and fields should not be modified or accessed directly. The creation of BIGNUM objects is described in BN_new(3); BN_add(3) describes most of the arithmetic operations. Comparison is described in BN_cmp(3); BN_zero(3) describes certain assignments, BN_rand(3) the generation of random numbers, BN_generate_prime(3) deals with prime numbers and BN_set_bit(3) with bit operations. The conversion of BIGNUMs to external formats is described in BN_bn2bin(3). SEE ALSO
bn_internal(3), dh(3), err(3), rand(3), rsa(3), BN_new(3), BN_CTX_new(3), BN_copy(3), BN_swap(3), BN_num_bytes(3), BN_add(3), BN_add_word(3), BN_cmp(3), BN_zero(3), BN_rand(3), BN_generate_prime(3), BN_set_bit(3), BN_bn2bin(3), BN_mod_inverse(3), BN_mod_mul_recip- rocal(3), BN_mod_mul_montgomery(3) 0.9.7d 2003-11-20 bn(3)
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