The
Transport Layer Security
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in secu ...
(TLS) protocol provides the ability to secure communications across networks. This comparison of TLS implementations compares several of the most notable
libraries
A library is a collection of materials, books or media that are accessible for use and not just for display purposes. A library provides physical (hard copies) or digital access (soft copies) materials, and may be a physical location or a vir ...
. There are several TLS implementations which are
free software
Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, ...
and
open source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...
.
All comparison categories use the stable version of each implementation listed in the overview section. The comparison is limited to features that directly relate to the TLS protocol.
Overview
TLS/SSL protocol version support
Several versions of the TLS protocol exist. SSL 2.0 is a deprecated
[ /tools.ietf.org/html/rfc6176 RFC 6176: Prohibiting Secure Sockets Layer (SSL) Version 2.0/ref> protocol version with significant weaknesses. SSL 3.0 (1996) and TLS 1.0 (1999) are successors with two weaknesses in CBC-padding that were explained in 2001 by Serge Vaudenay.]initialization vector
In cryptography, an initialization vector (IV) or starting variable (SV) is an input to a cryptographic primitive being used to provide the initial state. The IV is typically required to be random or pseudorandom, but sometimes an IV only needs to ...
s (IV) for CBC block ciphers, whereas the more problematic use of mac-pad-encrypt instead of the secure