BN_new, BN_clear, BN_free, BN_clear_free - allocate and free BIGNUMs
#include <openssl/bn.h> BIGNUM *BN_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_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.
BN_new() returns a pointer to the BIGNUM. If the allocation fails, it returns NULL and sets an error code that can be obtained by ERR_get_error.
BN_clear(), BN_free() and BN_clear_free() have no return values.
BN_init() was removed in OpenSSL 1.1.0; use BN_new() instead.