Messages in this thread | | | Subject | Re: Wanted: Secure-delete utility for Linux | Date | Wed, 23 Dec 1998 14:35:36 EST | From | Kev <> |
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> > Unfortunately the current /dev/random and /dev/urandom are very slow in > > generating data. Therefore I would rather like a /dev/frandom for fast, > > low quality randomness. > > Write a tiny program for the task, something like: [snip] > x =3D time(NULL);
This is already insecure; you can do better by reading 4 bytes from /dev/{u,}random as appropriate. Also, I would probably use a cryptographic hash function instead...if someone manages to recover one of the random numbers you've generated with this PRNG, they can recover the entire sequence; it's much more difficult to go back with an appropriate hash function. You should also be able to do other things that would hinder the forward prediction, as well... -- Kevin L. Mitchell <klmitch@mit.edu> ------------------------- -. .---- --.. ..- -..- -------------------------- http://web.mit.edu/klmitch/www/ (PGP keys availiable from here) RSA AE87D37D/1024: DE EA 1E 99 3F 2B F9 23 A0 D8 05 E0 6F BA B9 D2 DSS ED0DB34E/1024: D9BF 0E74 FDCB 43F5 C597 878F 9455 EC24 ED0D B34E DH 2A2C31D4/2048: 1A77 4BA5 9E32 14AE 87DA 9FEC 7106 FC62 2A2C 31D4
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