Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8532)
B<ctx> as an argument.
Finally, BN_CTX_end() must be called before returning from the function.
+If B<ctx> is NULL, nothing is done.
When BN_CTX_end() is called, the B<BIGNUM> pointers obtained from
BN_CTX_get() become invalid.
BN_clear() is used to destroy sensitive data such as keys when they
are no longer needed. It erases the memory used by B<a> and sets it
to the value 0.
+If B<a> is NULL, nothing is done.
BN_free() frees the components of the B<BIGNUM>, and if it was created
by BN_new(), also the structure itself. BN_clear_free() additionally