At 10:52 PM 4/20/96, Jeffrey I. Schiller wrote:
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On April 16, 1996 jf_avon@citenet.net said:
I fed the result of pgp +makerandom=2000 rnd.pgp into noisesphere.exe
Every times, it gives a distribution that looks like a zebra from the top view. Any comments?
This is a bug in PGP. +makerandom doesn't work properly. I discovered this a few week ago myself when I needed some random numbers for another project. Due to a programming bug, the idea based random number generator doesn't get initialized (read: doesn't get seeded at all) when +makerandom is used. Note: +makerandom is an undocumented feature.
IMPORTANT: Only +makerandom is effected. In normal use PGP properly generates random session keys as well as RSA public key pairs.
-Jeff
As true as this may be, it doesn't explain the original posters problem; unseeded IDEA should generate data that looks every bit as random as data which was fully seeded (otherwise IDEA leaks information). This should raise a question regarding the utility of any post-facto measurement of entropy; the stream of bits generate by IDEA encrypting zero values in CBC mode with a key of zero clearly has little, if any, entropy, but the data generated should be indistinguishable from true random data by all statistical and pattern-recognition tests. See the discussion on coderpunks. Basically, to get crypto-quality random numbers: 1) Use a secure generator; any secure block cipher or hash function will do. 2) Seed it well. This is entirely specific to your situation & platform, and is unmeasurable for practical purposes. - Tim Tim Dierks timd@consensus.com Consensus Development http://www.consensus.com