BN_CTX_new, BN_CTX_secure_new, BN_CTX_free - allocate and free BN_CTX structures
#include <openssl/bn.h>
BN_CTX *BN_CTX_new(void);
BN_CTX *BN_CTX_secure_new(void);
void BN_CTX_free(BN_CTX *c);
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.
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.
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);
ERR_get_error(3), BN_add(3), BN_CTX_start(3)
BN_CTX_init()
was removed in OpenSSL 1.1.0.
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.