xref: /openssl/doc/man3/BN_new.pod (revision faee6b21)
1=pod
2
3=head1 NAME
4
5BN_new, BN_secure_new, BN_clear, BN_free, BN_clear_free - allocate and free BIGNUMs
6
7=head1 SYNOPSIS
8
9 #include <openssl/bn.h>
10
11 BIGNUM *BN_new(void);
12
13 BIGNUM *BN_secure_new(void);
14
15 void BN_clear(BIGNUM *a);
16
17 void BN_free(BIGNUM *a);
18
19 void BN_clear_free(BIGNUM *a);
20
21=head1 DESCRIPTION
22
23BN_new() allocates and initializes a B<BIGNUM> structure.
24BN_secure_new() does the same except that the secure heap
25L<OPENSSL_secure_malloc(3)> is used to store the value.
26
27BN_clear() is used to destroy sensitive data such as keys when they
28are no longer needed. It erases the memory used by B<a> and sets it
29to the value 0.
30If B<a> is NULL, nothing is done.
31
32BN_free() frees the components of the B<BIGNUM>, and if it was created
33by BN_new(), also the structure itself. BN_clear_free() additionally
34overwrites the data before the memory is returned to the system.
35If B<a> is NULL, nothing is done.
36
37=head1 RETURN VALUES
38
39BN_new() and BN_secure_new()
40return a pointer to the B<BIGNUM> initialised to the value 0.
41If the allocation fails,
42they return B<NULL> and set an error code that can be obtained
43by L<ERR_get_error(3)>.
44
45BN_clear(), BN_free() and BN_clear_free() have no return values.
46
47=head1 SEE ALSO
48
49L<ERR_get_error(3)>, L<OPENSSL_secure_malloc(3)>
50
51=head1 HISTORY
52
53BN_init() was removed in OpenSSL 1.1.0; use BN_new() instead.
54
55=head1 COPYRIGHT
56
57Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
58
59Licensed under the Apache License 2.0 (the "License").  You may not use
60this file except in compliance with the License.  You can obtain a copy
61in the file LICENSE in the source distribution or at
62L<https://www.openssl.org/source/license.html>.
63
64=cut
65