SSL / TLS
Secure web servers, and many other kinds of servers that want to
protect data from prying eyes during transmission, often use the
Secure Socket Layer
developed by Netscape.
It is now also known as the Transport Layer Security protocol (TLS),
defined by the draft Internet standard
SSL, or more specifically, the RSA public-key cryptographic
operations usually used to exchange the session key at the start of
a connection, is computationally intensive.
It takes far more CPU time to establish an SSL connection than a normal connection.
This page lists products and sources of information of interest
to programmers trying to implement SSL in their software.
I'm just learning about this stuff myself, and these are the notes I'm making as I go.
- SSL and TLS, by Eric Rescorla
- the best book on SSL. Clear and informative. Includes OpenSSL examples. 500 pages. Read it now!
- SSL and TLS Essentials, by Stephen Thomas
- was the only good book on SSL until Rescorla's book came out. 200 pages. Thin but informative. (Out of print but still cheap used as of 2012.)
- OpenSSL - the leading open source SSL implementation.
See also the short OpenSSL tutorial at
- Mozilla's NSS SSL/TLS API
These guys invented SSL, they have an open source implementation,
dual-licensed under MPL and GPL, and maintain discussion groups on
- Peter Gutmann's Cryptlib -- open source, free for noncommercial use
- JDK 1.4
Sun's JDK 1.4 comes with SSL support (not just https support) built in.
- PureTLS -- a free Java-only implementation of SSLv3 and TLSv1.
- IAIK offers several products:
- JCE -- an independent reimplementation of Sun's JCE (javax.crypto) (commercial; free for noncommercial use)
- iSaSiLK -- an SSL layer on top of JCE (commercial; free for noncommercial use)
- an LGPL'd PKCS-11 wrapper library (LGPL)
LGPL'd implementation available.
In PKCS-11 lingo, an SSL accelerator is called a "hardware token".
CDSA ("Common Data Security Architecture") is an all-singing, all-dancing
standardized cryptography API backed by Intel and IBM, among others.
CDSA has a specification document and will have a compliance test suite,
so theoretically, anyone can write a CDSA library and check to see
whether they've done it properly; that alone makes me trust it more than
any Microsoft "standard" I know of. (If you think I'm being too hard
on Microsoft here, show me a conformance test suite for the win32 api,
and I'll eat my words.)
- Certicom's SSL Plus -
a commercial package that supports many operating systems, including
Linux, and at least one hardware accelerator (the Rainbow Cryptoswift).
- RSA's BSAFE BHAPI (not open source)
HP seems to have developed a small SSL benchmark called SSL_rate; see
the writeup at
Supposedly the code is downloadable from
ftp.cup.hp.com/dist/networking/benchmarks, but I haven't seen it yet.
In April, 2001, Coradiant published a
comparing a hand-coded highly optimized version of RSA for Itanium to
an unoptimized off-the-shelf generic RSA compiled for UltraSparc III.
(Gee, that's a fair test.) The original URL doesn't work anymore, but
Google saved a copy.
Last Real Update: 25 Sept 2001
Last Minor Update: 4 Sept 2012 (!)
Copyright 2000-2012, Dan Kegel
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