A local copy of OpenSSL from GitHub
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Rich Salz 4ef0ddc9d8 travis: enable markdownlint checks
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/11739)
3 years ago
.github CIFuzz turning dry_run off 3 years ago
Configurations Configurations: Identify the shell variables around MANSUFFIX 3 years ago
VMS Following the license change, modify the boilerplates in last few 5 years ago
apps SSL_OP_DISABLE_TLSEXT_CA_NAMES option implementation 3 years ago
boringssl@2070f8ad91 Update ossl_config.json for later BoringSSL commit 6 years ago
crypto EVP: when setting the operation to EVP_PKEY_OP_UNDEFINED, clean up! 3 years ago
demos Update copyright year 3 years ago
dev travis: enable markdownlint checks 3 years ago
doc SSL_OP_DISABLE_TLSEXT_CA_NAMES option implementation 3 years ago
engines In OpenSSL builds, declare STACK for datatypes ... 3 years ago
external/perl Update the bundled external perl module Text-Template to version 1.56 4 years ago
fuzz fuzz/asn1.c: Add missing #include 3 years ago
include SSL_OP_DISABLE_TLSEXT_CA_NAMES option implementation 3 years ago
krb5@890ca2f401 Update the krb5 submodule 3 years ago
ms Unify all assembler file generators 4 years ago
os-dep Move Haiku configuration to separate config file to denote 7 years ago
providers Add RSA SHA512 truncated digest support 3 years ago
pyca-cryptography@09403100de Update the pyca-cryptography submodule 5 years ago
ssl Fix use-after-free in BIO_C_SET_SSL callback 3 years ago
test SSL_OP_DISABLE_TLSEXT_CA_NAMES option implementation 3 years ago
tools Following the license change, modify the boilerplates in util/, tools/ 5 years ago
util travis: enable markdownlint checks 3 years ago
.gitattributes Developer scripts: Release script 3 years ago
.gitignore Update some nits around the FIPS module 3 years ago
.gitmodules [extended tests] Enable krb5 tests in Travis 6 years ago
.travis-apt-pin.preferences Fix travis clang-3.9 builds 6 years ago
.travis-create-release.sh Remove all 'make dist' artifacts 5 years ago
.travis.yml travis: enable markdownlint checks 3 years ago
ACKNOWLEDGEMENTS.md doc: introduce some minimalistic markdown without essential changes 3 years ago
AUTHORS.md doc: introduce some minimalistic markdown without essential changes 3 years ago
CHANGES.md Remove legacy FIPS_mode functions 3 years ago
CONTRIBUTING.md Fix links in CONTRIBUTING.md 3 years ago
Configure Configure: avoid perl regexp bugs 3 years ago
FAQ.md doc: introduce some minimalistic markdown without essential changes 3 years ago
HACKING A very brief explanation of how to add custom functions to OpenSSL. 4 years ago
INSTALL.md Build files: add module installation targets 3 years ago
LICENSE Change license to the Apache License v2.0 5 years ago
NEWS.md Prepare for 3.0 alpha 2 3 years ago
NOTES.ANDROID Andoid cross compile: change ANDROID_NDK_HOME to ANDROID_NDK_ROOT 3 years ago
NOTES.DJGPP Remove unnecessary trailing whitespace 4 years ago
NOTES.PERL Fix typo in NOTES.PERL 4 years ago
NOTES.UNIX NOTES.UNIX: add "Linking your application" paragraph 5 years ago
NOTES.VALGRIND Replace util/shlib_wrap.sh with util/wrap.pl in diverse docs 3 years ago
NOTES.VMS Remove unnecessary trailing whitespace 4 years ago
NOTES.WIN Configure: final cleanup of asm related things 4 years ago
README.ENGINE Remove bsd_cryptodev engine 6 years ago
README.FIPS Remove more (rest?) of FIPS build stuff. 7 years ago
README.md Add a link to wiki 3.0 upgrade notes 3 years ago
SUPPORT.md doc: revamp the SUPPORT file 3 years ago
VERSION Prepare for 3.0 alpha 2 3 years ago
appveyor.yml Add a minimal build target for Travis and Appveyor 3 years ago
build.info Add better support for using deprecated symbols internally 4 years ago
config Update copyright year 3 years ago
config.com Following the license change, modify the boilerplates in last few 5 years ago
configdata.pm.in configdata.pm.in: Don't try to quotify undefined values 4 years ago
e_os.h Update copyright year 3 years ago


openssl logo

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Welcome to the OpenSSL Project

OpenSSL is a robust, commercial-grade, full-featured Open Source Toolkit for the Transport Layer Security (TLS) protocol formerly known as the Secure Sockets Layer (SSL) protocol. The protocol implementation is based on a full-strength general purpose cryptographic library, which can also be used stand-alone.

OpenSSL is descended from the SSLeay library developed by Eric A. Young and Tim J. Hudson.

The official Home Page of the OpenSSL Project is www.openssl.org.

Table of Contents


The OpenSSL toolkit includes:

  • libssl an implementation of all TLS protocol versions up to TLSv1.3 (RFC 8446).

  • libcrypto a full-strength general purpose cryptographic library. It constitutes the basis of the TLS implementation, but can also be used independently.

  • openssl the OpenSSL command line tool, a swiss army knife for cryptographic tasks, testing and analyzing. It can be used for

    • creation of key parameters
    • creation of X.509 certificates, CSRs and CRLs
    • calculation of message digests
    • encryption and decryption
    • SSL/TLS client and server tests
    • handling of S/MIME signed or encrypted mail
    • and more...


For Production Use

Source code tarballs of the official releases can be downloaded from www.openssl.org/source. The OpenSSL project does not distribute the toolkit in binary form.

However, for a large variety of operating systems precompiled versions of the OpenSSL toolkit are available. In particular on Linux and other Unix operating systems it is normally recommended to link against the precompiled shared libraries provided by the distributor or vendor.

For Testing and Development

Although testing and development could in theory also be done using the source tarballs, having a local copy of the git repository with the entire project history gives you much more insight into the code base.

The official OpenSSL Git Repository is located at git.openssl.org. There is a GitHub mirror of the repository at github.com/openssl/openssl, which is updated automatically from the former on every commit.

A local copy of the Git Repository can be obtained by cloning it from the original OpenSSL repository using

    git clone git://git.openssl.org/openssl.git

or from the GitHub mirror using

    git clone https://github.com/openssl/openssl.git

If you intend to contribute to OpenSSL, either to fix bugs or contribute new features, you need to fork the OpenSSL repository openssl/openssl on GitHub and clone your public fork instead.

    git clone https://github.com/yourname/openssl.git

This is necessary, because all development of OpenSSL nowadays is done via GitHub pull requests. For more details, see Contributing.

Build and Install

After obtaining the Source, have a look at the INSTALL file for detailed instructions about building and installing OpenSSL. For some platforms, the installation instructions are amended by a platform specific document.

Specific notes on upgrading to OpenSSL 3.0 from previous versions, as well as known issues are available on the OpenSSL wiki.


Manual Pages

The manual pages for the master branch and all current stable releases are available online.


There is a Wiki at wiki.openssl.org which is currently not very active. It contains a lot of useful information, not all of which is up to date.


OpenSSL is licensed under the Apache License 2.0, which means that you are free to get and use it for commercial and non-commercial purposes as long as you fulfill its conditions.

See the LICENSE file for more details.


There are various ways to get in touch. The correct channel depends on your requirement. see the SUPPORT file for more details.


If you are interested and willing to contribute to the OpenSSL project, please take a look at the CONTRIBUTING file.

Since 2016, development takes place in public on the GitHub open source platform. The OpenSSL Project Pages at openssl.github.io are a valuable source of information if you want to get familiar with our development process on GitHub.


A number of nations restrict the use or export of cryptography. If you are potentially subject to such restrictions you should seek legal advice before attempting to develop or distribute cryptographic code.


Copyright (c) 1998-2020 The OpenSSL Project

Copyright (c) 1995-1998 Eric A. Young, Tim J. Hudson

All rights reserved.