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=head1 NAME

crypto - OpenSSL cryptographic library

=head1 SYNOPSIS

See the individual manual pages for details.

=head1 DESCRIPTION

The OpenSSL B<crypto> library implements a wide range of cryptographic
algorithms used in various Internet standards. The services provided
by this library are used by the OpenSSL implementations of SSL, TLS
and S/MIME, and they have also been used to implement SSH, OpenPGP, and
other cryptographic standards.

B<libcrypto> consists of a number of sub-libraries that implement the
individual algorithms.

The functionality includes symmetric encryption, public key
cryptography and key agreement, certificate handling, cryptographic
hash functions, cryptographic pseudo-random number generator, and
various utilities.

=head1 NOTES

Some of the newer functions follow a naming convention using the numbers
B<0> and B<1>. For example the functions:

 int X509_CRL_add0_revoked(X509_CRL *crl, X509_REVOKED *rev);
 int X509_add1_trust_object(X509 *x, const ASN1_OBJECT *obj);

The B<0> version uses the supplied structure pointer directly
in the parent and it will be freed up when the parent is freed.
In the above example B<crl> would be freed but B<rev> would not.

The B<1> function uses a copy of the supplied structure pointer
(or in some cases increases its link count) in the parent and
so both (B<x> and B<obj> above) should be freed up.

=head1 RETURN VALUES

See the individual manual pages for details.

=head1 SEE ALSO

L<openssl(1)>, L<ssl(7)>

=head1 COPYRIGHT

Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (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
L<https://www.openssl.org/source/license.html>.

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