Date: Sun, 25 May 2008 16:10:01 -0400 From: "Aryeh M. Friedman" <aryeh.friedman@gmail.com> To: fbsd_chat <freebsd-chat@freebsd.org> Subject: [OT] looking for a algorithm Message-ID: <4839C799.6020104@gmail.com>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Lets say I have a string of n bits that needs to be filled by repeatedly applying some function on k strings of m bits where |m|<|n|. Assuming that m(i) is a random string and n needs to also be random what is the best way to do this. Note it is possible that k*|m|>|n|. What I have been thinking so far is: ~ Let m' be the average length of m // this is pre-computable ~ Let n be all 0's ~ for i=0 --> k ~ pos=m'*i ~ xor string k[i] onto n starting at pos // wrap around if needed ~ While this is simple I wonder if it can be attacked (determine what k[i]) if k*|m|>|n| (it is trivial to attack if k*|m|<=|n|). Also is there some way to make attacking hard if k*|m|<=|n|? ~ Ideas? -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkg5x5gACgkQk8GFzCrQm4C47wCfVLGiXFwILBsRIoZ3Sx3fpMf7 DrsAn1Fr196aTJ3vMUFJ21+sqM0AZdB8 =UF9N -----END PGP SIGNATURE-----
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