A local copy of OpenSSL from GitHub
You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Pauli 5b286641ef apps: avoid memory overrun.
NULL terminate the built in "help" argv array to avoid
reading beyond the end.

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/12258)
3 years ago
.github Add github sponsor button 3 years ago
Configurations Configure DEPs for FIPS provider on AIX. 3 years ago
VMS Following the license change, modify the boilerplates in last few 5 years ago
apps apps: avoid memory overrun. 3 years ago
boringssl@2070f8ad91 Update ossl_config.json for later BoringSSL commit 6 years ago
crypto evp_rand: documentation 3 years ago
demos Cleanup cert config files for tests 3 years ago
dev dev/release.sh: Add --reviewer to set reviewers 3 years ago
doc Fix some man page typos 3 years ago
engines Update copyright year 3 years ago
external/perl Update the bundled external perl module Text-Template to version 1.56 4 years ago
fuzz Improve ossl_cmp_msg_check_received() and rename to ossl_cmp_msg_check_update() 3 years ago
gost-engine@30860f9403 Update gost-engine submodule to match EVP_MAC renaming 3 years ago
include fips rand: DRBG KAT self test updates to provider model. 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 include source root directory via -I for libnonfips.a 3 years ago
pyca-cryptography@09403100de Update the pyca-cryptography submodule 5 years ago
ssl Don't attempt to duplicate the BIO state in SSL_dup 3 years ago
test test: add test for generation of random data in chunks. 3 years ago
tools Following the license change, modify the boilerplates in util/, tools/ 5 years ago
util evp_rand: documentation 3 years ago
.gitattributes Developer scripts: Release script 3 years ago
.gitignore Add evp_extra_test2 to .gitignore 3 years ago
.gitmodules GOST external tests 3 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 Avoid undefined behavior with unaligned accesses 3 years ago
ACKNOWLEDGEMENTS.md Fix issues reported by markdownlint 3 years ago
AUTHORS.md Fix issues reported by markdownlint 3 years ago
CHANGES.md The EVP_MAC functions have been renamed for consistency. The EVP_MAC_CTX_* 3 years ago
CONTRIBUTING.md Fix issues reported by markdownlint 3 years ago
Configure Add ACVP fips module tests 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 DOC: Fix link to test/README.external in INSTALL.md 3 years ago
LICENSE Change license to the Apache License v2.0 5 years ago
NEWS.md APPS: Drop interactive mode in the 'openssl' program 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 Update and extend NOTES.WIN, adding 'Quick start' subsection 3 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 Update and extend NOTES.WIN, adding 'Quick start' subsection 3 years ago
README.ENGINE Remove bsd_cryptodev engine 6 years ago
README.FIPS Remove more (rest?) of FIPS build stuff. 8 years ago
README.md Fix issues reported by markdownlint 3 years ago
SUPPORT.md Fix issues reported by markdownlint 3 years ago
VERSION Prepare for 3.0 alpha 4 3 years ago
appveyor.yml Prevent extended tests run unexpectedly in 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


Welcome to the OpenSSL Project

openssl logo

travis badge appveyor badge

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.