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- OpenSSL version differences
- Sun /dev/urandom patch information
This commit is contained in:
Bodo Möller 2003-02-04 12:28:11 +00:00
parent 2619676256
commit c09a297892
1 changed files with 23 additions and 23 deletions
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46
FAQ
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@ -189,18 +189,30 @@ for permission to use their software with OpenSSL.
Cryptographic software needs a source of unpredictable data to work
correctly. Many open source operating systems provide a "randomness
device" that serves this purpose. On other systems, applications have
to call the RAND_add() or RAND_seed() function with appropriate data
before generating keys or performing public key encryption.
(These functions initialize the pseudo-random number generator, PRNG.)
device" (/dev/urandom or /dev/random) that serves this purpose.
All OpenSSL versions try to use /dev/urandom by default; starting with
version 0.9.7, OpenSSL also tries /dev/random is /dev/urandom is not
available.
Some broken applications do not do this. As of version 0.9.5, the
OpenSSL functions that need randomness report an error if the random
number generator has not been seeded with at least 128 bits of
randomness. If this error occurs, please contact the author of the
application you are using. It is likely that it never worked
correctly. OpenSSL 0.9.5 and later make the error visible by refusing
to perform potentially insecure encryption.
On other systems, applications have to call the RAND_add() or
RAND_seed() function with appropriate data before generating keys or
performing public key encryption. (These functions initialize the
pseudo-random number generator, PRNG.) Some broken applications do
not do this. As of version 0.9.5, the OpenSSL functions that need
randomness report an error if the random number generator has not been
seeded with at least 128 bits of randomness. If this error occurs and
is not discussed in the documentation of the application you are
using, please contact the author of that application; it is likely
that it never worked correctly. OpenSSL 0.9.5 and later make the
error visible by refusing to perform potentially insecure encryption.
If you are using Solaris 8, you can add /dev/urandom and /dev/random
devices by installing patch 112438 (Sparc) or 112439 (x86), which are
available via the Patchfinder at <URL: http://sunsolve.sun.com>
(Solaris 9 includes these devices by default). For /dev/random support
for earlier Solaris versions, see Sun's statement at
<URL: http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=fsrdb/27606&zone_32=SUNWski>
(the SUNWski package is available in patch 105710).
On systems without /dev/urandom and /dev/random, it is a good idea to
use the Entropy Gathering Demon (EGD); see the RAND_egd() manpage for
@ -233,18 +245,6 @@ OpenSSL command line tools. Applications using the OpenSSL library
provide their own configuration options to specify the entropy source,
please check out the documentation coming the with application.
For Solaris 2.6, Tim Nibbe <tnibbe@sprint.net> and others have suggested
installing the SUNski package from Sun patch 105710-01 (Sparc) which
adds a /dev/random device and make sure it gets used, usually through
$RANDFILE. There are probably similar patches for the other Solaris
versions. An official statement from Sun with respect to /dev/random
support can be found at
http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=fsrdb/27606&zone_32=SUNWski
However, be warned that /dev/random is usually a blocking device, which
may have some effects on OpenSSL.
A third party /dev/random solution for Solaris is available at
http://www.cosy.sbg.ac.at/~andi/
* Why do I get an "unable to write 'random state'" error message?