NAME

BN_new, BN_init, BN_clear, BN_free, BN_clear_free - allocate and free BIGNUMs

SYNOPSIS

 #include <openssl/bn.h>

 BIGNUM *BN_new(void);

 void BN_clear(BIGNUM *a);

 void BN_free(BIGNUM *a);

 void BN_clear_free(BIGNUM *a);

DESCRIPTION

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.

RETURN VALUES

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.

REMOVED FUNCTIONALITY

 void BN_init(BIGNUM *);

BN_init() is no longer available as of OpenSSL 1.1.0. It was used to initialize an existing uninitialized BIGNUM. Typically this would be done as follows:

 BIGNUM a;
 BN_init(&a);

Applications should replace use of BN_init with BN_new instead:

 BIGNUM *a;
 a = BN_new();
 if(!a) /* Handle error */
 ...
 BN_free(a);

SEE ALSO

bn, ERR_get_error

HISTORY

BN_new(), BN_clear(), BN_free() and BN_clear_free() are available in all versions on SSLeay and OpenSSL. BN_init() was added in SSLeay 0.9.1b and removed in OpenSSL 1.1.0.