Rewording: some algorithms are also patented in Europe, so choose more

[openssl.git] / FAQ

diff --git a/FAQ b/FAQ
index fae0b855bf82d847ef64da709422d01909c4fca2..45566252f45821543ed877cfb0d4ca08d79264d3 100644 (file)
--- a/FAQ
+++ b/FAQ
@@ -39,6 +39,7 @@ OpenSSL  -  Frequently Asked Questions
 * Why does the OpenSSL compilation fail on Alpha Tru64 Unix?
 * Why does the OpenSSL compilation fail with "ar: command not found"?
 * Why does the OpenSSL compilation fail on Win32 with VC++?
+* What is special about OpenSSL on Redhat?
 
 [PROG] Questions about programming with OpenSSL
 
@@ -463,6 +464,38 @@ under 'Program Files').  This needs to be done prior to running NMAKE,
 and the changes are only valid for the current DOS session.
 
 
+* What is special about OpenSSL on Redhat?
+
+Red Hat Linux (release 7.0 and later) include a preinstalled limited
+version of OpenSSL. For patent reasons, support for IDEA, RC5 and MDC2
+is disabled in this version. The same may apply to other Linux distributions.
+Users may therefore wish to install more or all of the features left out.
+
+To do this you MUST ensure that you do not overwrite the openssl that is in
+/usr/bin on your Red Hat machine. Several packages depend on this file,
+including sendmail and ssh. /usr/local/bin is a good alternative choice. The
+libraries that come with Red Hat 7.0 onwards have different names and so are
+not affected. (eg For Red Hat 7.2 they are /lib/libssl.so.0.9.6b and
+/lib/libcrypto.so.0.9.6b with symlinks /lib/libssl.so.2 and
+/lib/libcrypto.so.2 respectively).
+
+Please note that we have been advised by Red Hat attempting to recompile the
+openssl rpm with all the cryptography enabled will not work. All other
+packages depend on the original Red Hat supplied openssl package. It is also
+worth noting that due to the way Red Hat supplies its packages, updates to
+openssl on each distribution never change the package version, only the
+build number. For example, on Red Hat 7.1, the latest openssl package has
+version number 0.9.6 and build number 9 even though it contains all the
+relevant updates in packages up to and including 0.9.6b.
+
+A possible way around this is to persuade Red Hat to produce a non-US
+version of Red Hat Linux.
+
+FYI: Patent numbers and expiry dates of US patents:
+MDC-2: 4,908,861 13/03/2007
+IDEA:  5,214,703 25/05/2010
+RC5:   5,724,428 03/03/2015
+
 [PROG] ========================================================================
 
 * Is OpenSSL thread-safe?