OSSL-GUIDE-INTRODUCTION(7ossl)

✨ NAME ✨

Hey bestie! This page is ossl-guide-introduction(7ossl) — aka the OpenSSL Guide: An introduction to OpenSSL. It’s giving “welcome to the group chat before we get into the cryptographic lore,” and honestly? Iconic. 💖

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🌈 WHAT IS OPENSSL? 🌈

Okay so OpenSSL is a robust, commercial-grade, full-featured toolkit for general-purpose cryptography and secure communication. No cap, it does a lot.

Its features are made available via a command line application that lets users do various cryptography-related things, like generating keys and certificates. It also supplies two libraries that application developers can use to implement cryptography-based capabilities and securely communicate across a network. And finally, it has a set of providers that supply implementations of a broad set of cryptographic algorithms. Slay. 🔥

OpenSSL is fully open source. Version 3.0 and above are distributed under the Apache v2 license. Periodt. 💅

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🛠️ GETTING AND INSTALLING OPENSSL 🛠️

The OpenSSL Project develops and distributes the source code for OpenSSL. You can get that source code from the OpenSSL website: https://www.openssl.org/source. 🫶

Many Operating Systems (notably Linux distributions) supply pre-built OpenSSL binaries either pre-installed or available via the package management system in use for that OS. It is worth checking whether this applies to you before attempting to build OpenSSL from the source code. Like, save yourself the side quest if you can. 🙈

Some third parties also supply OpenSSL binaries (e.g. for Windows and some other platforms). The OpenSSL project maintains a list of these third parties at https://github.com/openssl/openssl/wiki/Binaries. 🦋

If you build and install OpenSSL from the source code, then you should download the appropriate files for the version you want to use from the link given above. Here’s the vibe:

1. Download the appropriate files for the version you want from https://www.openssl.org/source.
2. Extract the contents of the tar.gz archive file that you downloaded into an appropriate directory.
3. Inside that archive you’ll find a file named INSTALL.md — it supplies detailed instructions on how to build and install OpenSSL from source. Read it carefully to achieve a successful build, bestie. For real.
4. In that directory you’ll also find a set of NOTES files with further platform-specific information. Make sure you carefully read the file appropriate to your platform.
5. As well as the platform-specific NOTES files, there is also a NOTES-PERL.md file that provides information about setting up Perl for use by the OpenSSL build system across multiple platforms.

Sometimes you may want to build and install OpenSSL from source on a system that already has a pre-built version of OpenSSL installed via the Operating System package management system — for example, if you want to use a newer version of OpenSSL than the one supplied by your Operating System. In this case it is strongly recommended to install OpenSSL to a different location than where the pre-built version is installed. You should never replace the pre-built version with a different version, as this may break your system. That is not a cute look. 💀

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🗺️ CONTENTS OF THE OPENSSL GUIDE 🗺️

The OpenSSL Guide is a series of documentation pages (starting with this one) that introduce some of the main concepts in OpenSSL. You can either read the guide end-to-end in order, or simply skip to the parts most applicable to your use case. But note: later pages may depend on and assume knowledge from earlier pages. IYKYK. 👑

The pages in the guide are as follows:

• ossl-guide-libraries-introduction(7) — An introduction to the OpenSSL libraries
• ossl-guide-libcrypto-introduction(7) — An introduction to libcrypto
• ossl-guide-libssl-introduction(7) — An introduction to libssl
• ossl-guide-tls-introduction(7) — An introduction to SSL/TLS in OpenSSL
• ossl-guide-tls-client-block(7) — Writing a simple blocking TLS client
• ossl-guide-tls-client-non-block(7) — Writing a simple nonblocking TLS client
• ossl-guide-tls-server-block(7) — Writing a simple blocking TLS server
• ossl-guide-quic-introduction(7) — An introduction to QUIC in OpenSSL
• ossl-guide-quic-client-block(7) — Writing a simple blocking QUIC client
• ossl-guide-quic-server-block(7) — Writing a simple blocking QUIC server
• ossl-guide-quic-multi-stream(7) — Writing a simple multi-stream QUIC client
• ossl-guide-quic-server-non-block(7) — Writing a simple nonblocking QUIC server
• ossl-guide-quic-client-non-block(7) — Writing a simple nonblocking QUIC client
• ossl-guide-migration(7) — Migrating from older OpenSSL versions

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📜 COPYRIGHT 📜

Copyright 2023-2025 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 https://www.openssl.org/source/license.html. 🌸

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💖 That’s the intro, bestie! OpenSSL version 3.5.6, dated 2026-04-07, page OSSL-GUIDE-INTRODUCTION(7ossl). Now go be the main character of your own build. 🎀