1=pod 2 3=head1 NAME 4 5ossl-guide-introduction 6- OpenSSL Guide: An introduction to OpenSSL 7 8=head1 WHAT IS OPENSSL? 9 10OpenSSL is a robust, commercial-grade, full-featured toolkit for general-purpose 11cryptography and secure communication. Its features are made available via a 12command line application that enables users to perform various cryptography 13related functions such as generating keys and certificates. Additionally it 14supplies two libraries that application developers can use to implement 15cryptography based capabilities and to securely communicate across a network. 16Finally, it also has a set of providers that supply implementations of a broad 17set of cryptographic algorithms. 18 19OpenSSL is fully open source. Version 3.0 and above are distributed under the 20Apache v2 license. 21 22=head1 GETTING AND INSTALLING OPENSSL 23 24The OpenSSL Project develops and distributes the source code for OpenSSL. You 25can obtain that source code via the OpenSSL website 26(L<https://www.openssl.org/source>). 27 28Many Operating Systems (notably Linux distributions) supply pre-built OpenSSL 29binaries either pre-installed or available via the package management system in 30use for that OS. It is worth checking whether this applies to you before 31attempting to build OpenSSL from the source code. 32 33Some third parties also supply OpenSSL binaries (e.g. for Windows and some other 34platforms). The OpenSSL project maintains a list of these third parties at 35L<https://wiki.openssl.org/index.php/Binaries>. 36 37If you build and install OpenSSL from the source code then you should download 38the appropriate files for the version that you want to use from the link given 39above. Extract the contents of the B<tar.gz> archive file that you downloaded 40into an appropriate directory. Inside that archive you will find a file named 41B<INSTALL.md> which will supply detailed instructions on how to build and 42install OpenSSL from source. Make sure you read the contents of that file 43carefully in order to achieve a successful build. In the directory you will also 44find a set of B<NOTES> files that provide further platform specific information. 45Make sure you carefully read the file appropriate to your platform. As well as 46the platform specific B<NOTES> files there is also a B<NOTES-PERL.md> file that 47provides information about setting up Perl for use by the OpenSSL build system 48across multiple platforms. 49 50Sometimes you may want to build and install OpenSSL from source on a system 51which already has a pre-built version of OpenSSL installed on it via the 52Operating System package management system (for example if you want to use a 53newer version of OpenSSL than the one supplied by your Operating System). In 54this case it is strongly recommended to install OpenSSL to a different location 55than where the pre-built version is installed. You should B<never> replace the 56pre-built version with a different version as this may break your system. 57 58=head1 CONTENTS OF THE OPENSSL GUIDE 59 60The OpenSSL Guide is a series of documentation pages (starting with this one) 61that introduce some of the main concepts in OpenSSL. The guide can either be 62read end-to-end in order, or alternatively you can simply skip to the parts most 63applicable to your use case. Note however that later pages may depend on and 64assume knowledge from earlier pages. 65 66The pages in the guide are as follows: 67 68=over 4 69 70=item L<ossl-guide-libraries-introduction(7)>: An introduction to the OpenSSL libraries 71 72=item L<ossl-guide-libcrypto-introduction(7)>: An introduction to libcrypto 73 74=item L<ossl-guide-libssl-introduction(7)>: An introduction to libssl 75 76=item L<ossl-guide-tls-introduction(7)>: An introduction to SSL/TLS in OpenSSL 77 78=item L<ossl-guide-tls-client-block(7)>: Writing a simple blocking TLS client 79 80=item L<ossl-guide-tls-client-non-block(7)>: Writing a simple nonblocking TLS client 81 82=item L<ossl-guide-tls-server-block(7)>: Writing a simple blocking TLS server 83 84=item L<ossl-guide-quic-introduction(7)>: An introduction to QUIC in OpenSSL 85 86=item L<ossl-guide-quic-client-block(7)>: Writing a simple blocking QUIC client 87 88=item L<ossl-guide-quic-multi-stream(7)>: Writing a simple multi-stream QUIC client 89 90=item L<ossl-guide-quic-client-non-block(7)>: Writing a simple nonblocking QUIC client 91 92=item L<ossl-guide-migration(7)>: Migrating from older OpenSSL versions 93 94=back 95 96=head1 COPYRIGHT 97 98Copyright 2023-2024 The OpenSSL Project Authors. All Rights Reserved. 99 100Licensed under the Apache License 2.0 (the "License"). You may not use 101this file except in compliance with the License. You can obtain a copy 102in the file LICENSE in the source distribution or at 103L<https://www.openssl.org/source/license.html>. 104 105=cut 106
