5 BN_CTX_new, BN_CTX_secure_new, BN_CTX_init, BN_CTX_free - allocate and free BN_CTX structures
9 #include <openssl/bn.h>
11 BN_CTX *BN_CTX_new(void);
13 BN_CTX *BN_CTX_secure_new(void);
15 void BN_CTX_free(BN_CTX *c);
19 A B<BN_CTX> is a structure that holds B<BIGNUM> temporary variables used by
20 library functions. Since dynamic memory allocation to create B<BIGNUM>s
21 is rather expensive when used in conjunction with repeated subroutine
22 calls, the B<BN_CTX> structure is used.
24 BN_CTX_new() allocates and initializes a B<BN_CTX> structure.
25 BN_CTX_secure_new() allocates and initializes a B<BN_CTX> structure
26 but uses the secure heap (see L<CRYPTO_secure_malloc(3)>) to hold the
29 BN_CTX_free() frees the components of the B<BN_CTX>, and if it was
30 created by BN_CTX_new(), also the structure itself.
31 If L<BN_CTX_start(3)|BN_CTX_start(3)> has been used on the B<BN_CTX>,
32 L<BN_CTX_end(3)|BN_CTX_end(3)> must be called before the B<BN_CTX>
33 may be freed by BN_CTX_free().
34 If B<c> is NULL, nothing is done.
38 BN_CTX_new() and BN_CTX_secure_new() return a pointer to the B<BN_CTX>.
39 If the allocation fails,
40 they return B<NULL> and sets an error code that can be obtained by
41 L<ERR_get_error(3)|ERR_get_error(3)>.
43 BN_CTX_free() has no return values.
45 =head1 REMOVED FUNCTIONALITY
47 void BN_CTX_init(BN_CTX *c);
49 BN_CTX_init() is no longer available as of OpenSSL 1.1.0. Applications should
50 replace use of BN_CTX_init with BN_CTX_new instead:
54 if(!ctx) /* Handle error */
60 L<bn(3)|bn(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<BN_add(3)|BN_add(3)>,
61 L<BN_CTX_start(3)|BN_CTX_start(3)>
65 BN_CTX_new() and BN_CTX_free() are available in all versions on SSLeay
66 and OpenSSL. BN_CTX_init() was added in SSLeay 0.9.1b and removed in OpenSSL