BN_new.3ssl man page

BN_new, BN_secure_new, BN_clear, BN_free, BN_clear_free — allocate and free BIGNUMs


#include <openssl/bn.h>
BIGNUM *BN_new(void);
BIGNUM *BN_secure_new(void);
void BN_clear(BIGNUM *a);
void BN_free(BIGNUM *a);
void BN_clear_free(BIGNUM *a);


BN_new() allocates and initializes a BIGNUM structure. BN_secure_new() does the same except that the secure heap OPENSSL_secure_malloc(3) is used to store the value.

BN_clear() is used to destroy sensitive data such as keys when they are no longer needed. It erases the memory used by a and sets it to the value 0.

BN_free() frees the components of the BIGNUM, and if it was created by BN_new(), also the structure itself. BN_clear_free() additionally overwrites the data before the memory is returned to the system. If a is NULL, nothing is done.

Return Values

BN_new() and BN_secure_new() return a pointer to the BIGNUM. If the allocation fails, they return NULL and set an error code that can be obtained by ERR_get_error(3).

BN_clear(), BN_free() and BN_clear_free() have no return values.

See Also

bn(3), ERR_get_error(3)


BN_init() was removed in OpenSSL 1.1.0; use BN_new() instead.


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