BN_CTX_NEW(3) OpenSSL BN_CTX_NEW(3)
NAME
BN_CTX_new, BN_CTX_secure_new, BN_CTX_free - allocate and free BN_CTX
structures
SYNOPSIS
#include <openssl/bn.h>
BN_CTX *BN_CTX_new(void);
BN_CTX *BN_CTX_secure_new(void);
void BN_CTX_free(BN_CTX *c);
DESCRIPTION
A BN_CTX is a structure that holds BIGNUM temporary variables used by
library functions. Since dynamic memory allocation to create BIGNUMs is
rather expensive when used in conjunction with repeated subroutine
calls, the BN_CTX structure is used.
BN_CTX_new() allocates and initializes a BN_CTX structure.
BN_CTX_secure_new() allocates and initializes a BN_CTX structure but
uses the secure heap (see CRYPTO_secure_malloc(3)) to hold the BIGNUMs.
BN_CTX_free() frees the components of the BN_CTX and the structure
itself. Since BN_CTX_start() is required in order to obtain BIGNUMs
from the BN_CTX, in most cases BN_CTX_end() must be called before the
BN_CTX may be freed by BN_CTX_free(). If c is NULL, nothing is done.
A given BN_CTX must only be used by a single thread of execution. No
locking is performed, and the internal pool allocator will not properly
handle multiple threads of execution.
RETURN VALUES
BN_CTX_new() and BN_CTX_secure_new() return a pointer to the BN_CTX.
If the allocation fails, they return NULL and sets an error code that
can be obtained by ERR_get_error(3).
BN_CTX_free() has no return values.
REMOVED FUNCTIONALITY
void BN_CTX_init(BN_CTX *c);
BN_CTX_init() is no longer available as of OpenSSL 1.1.0. Applications
should replace use of BN_CTX_init with BN_CTX_new instead:
BN_CTX *ctx;
ctx = BN_CTX_new();
if (!ctx)
/* error */
...
BN_CTX_free(ctx);
SEE ALSO
ERR_get_error(3), BN_add(3), BN_CTX_start(3)
HISTORY
BN_CTX_init() was removed in OpenSSL 1.1.0.
COPYRIGHT
Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>.
1.1.1k 2021-03-25 BN_CTX_NEW(3)