ANN: Crypt::ISAAC 0.9.1 released

[Kirk Haines]

This release is primarily a reorganization of the old package. It has a much
better installer, a basic unit test suite, better README and licensing info,
and a gem has been built for Crypt::ISAAC as well. The only functionality
change is to add an option when creating a new generator that will force it
to try to use /dev/random to seed the generator, instead of /dev/urandom
(falling back to rand() if neither is available). This is an experimental
feature -- seeding from /dev/random appears to be almost too slow to be
usable since so much entropy is needed, but to use it, create pass false when
creating the object, as follows:

prng = Crypt::ISAAC.new(false)

The code should run anywhere that Ruby does, though there will be support for
better seeding of the prng on Windows coming soon.

The package has been uploaded to Rubyforge:

http://rubyforge.org/project/crypt-isaac

Here is the README:

Crypt::ISAAC README
============

ISAAC is a cryptographically secure PRNG for generating high quality random
numbers. Detailed information about the algorithm can be found at:

http://burtleburtle.net/bob/rand/isaac.html

This is a pure Ruby implementation of the algorithm. It is reasonably fast
for
a pure Ruby implementation. On an 800Mhz PIII computer running Ruby 1.8.2,
and while the machine is also serving as general desktop, the library seems to
consistently generate between 15000 and 16000 random numbers per second.

Ruby uses the Mersenne Twister as its PRNG, and while this the Twister is
a fast PRNG that produces highly random numbers, it is not strong for
cryptographic purposes, nor is it suitable when one needs multiple
independent streams of random numbers. Crypt::ISAAC is suitable for either
purpose.

Requirements
------------

* Ruby 1.8 (should also run on 1.6.x)

Install
-------

If you have never installed Crypt::ISAAC, you may run the testsuite
to confirm that it works with:

# ruby setup.rb test

If you already have a version of Crypt::ISAAC installed, but want to
confirm this one before installing, run the test suite manually as
follows:

# ruby test/TC_ISAAC.rb local

When you are ready to install Crypt::ISAAC, type:

# ruby setup.rb install

This one step will install Crypt::ISAAC in your Ruby SITELIB. To test
the library after installation:

# ruby setup.rb test

Usage
-----

require 'crypt/ISAAC'

rng = Crypt::ISAAC.new

r1 = rng.rand() # returns a floating point between 0 and 1
r2 = rnd.rand(1000) # returns an integer between 0 and 999

rand() should work identically to the Kernel.rand().

Enjoy it. Let me know if you find anything that can be improved or that
needs to be fixed.

License
-------

The Crypt::ISAAC library is licensed with an MIT style licence.
See the LICENSE file for details. As for the ISAAC algorithm itself,
see:

http://burtleburtle.net/bob/rand/isaac.html

Please let me know if you run into any problem, especially with the gem. This
is the first gem that I have produced.

Kirk Haines
kha...@enigo.com

[Daniel Berger]

Ew. I'd prefer it if everyone would use lowercase for all package files.
Between "win32ole" and "Win32API", I developed a bit of a complex about this.

Otherwise, cool. :)

Regards,

Dan

[Daniel Berger]

Kirk Haines wrote:
> This release is primarily a reorganization of the old package. It has a much
> better installer, a basic unit test suite, better README and licensing info,
> and a gem has been built for Crypt::ISAAC as well. The only functionality
> change is to add an option when creating a new generator that will force it
> to try to use /dev/random to seed the generator, instead of /dev/urandom
> (falling back to rand() if neither is available). This is an experimental
> feature -- seeding from /dev/random appears to be almost too slow to be
> usable since so much entropy is needed, but to use it, create pass false when
> creating the object, as follows:
>
> prng = Crypt::ISAAC.new(false)

I got some improvement when I replaced "read" with "sysread" in ISAAC.rb.
Here's a little benchmark script I wrote:

require "crypt/ISAAC"
require "benchmark"
include Benchmark

MAX = ARGV[0] || 100

bm do |x|
x.report("rand"){
MAX.times{ Crypt::ISAAC.new(true) }
}

x.report("/dev"){
MAX.times{ Crypt::ISAAC.new(false) }
}
end

Results:

# Using read
>ruby bench_isaac.rb
user system total real
rand 6.290000 0.410000 6.700000 ( 6.928163)
/dev 6.490000 9.640000 16.130000 ( 23.197032)

# Using sysread
>ruby bench_isaac.rb
user system total real
rand 6.340000 0.550000 6.890000 ( 7.148228)
/dev 6.560000 3.050000 9.610000 ( 9.976435)

This was on a stock Sunblade 150 running Solaris 10.

Regards,

Dan

[Kirk Haines]

On Thursday 13 October 2005 10:50 am, Daniel Berger wrote:
> I got some improvement when I replaced "read" with "sysread" in ISAAC.rb.
> Here's a little benchmark script I wrote:

I'll make that change.

> bm do |x|
> x.report("rand"){
> MAX.times{ Crypt::ISAAC.new(true) }
> }
>
> x.report("/dev"){
> MAX.times{ Crypt::ISAAC.new(false) }
> }
> end

The default is true, which means to use the nonblocking entropy source
(/dev/urandom), and while false tells it to use /dev/random. It only uses
rand() if it can't find the /dev/urandom (or /dev/random if told to use
that). So your timings that you have labeled "rand" are using /dev/urandom,
and the one labeld "/dev" is using /dev/random.

> # Using read
>
> >ruby bench_isaac.rb
>
> user system total real
> rand 6.290000 0.410000 6.700000 ( 6.928163)
> /dev 6.490000 9.640000 16.130000 ( 23.197032)
>
> # Using sysread
>
> >ruby bench_isaac.rb
>
> user system total real
> rand 6.340000 0.550000 6.890000 ( 7.148228)
> /dev 6.560000 3.050000 9.610000 ( 9.976435)

I'm surprised it was that fast, actually. On my boxes, I had FAR less entropy
in /dev/random available to me. I actually thought that something was wrong
with my code the first time I tested it, it was so slow. :)

Thanks for the feedback,

Kirk Haines