Date: Sun, 23 Sep 2001 06:02:26 -0400 (EDT) From: Michael Shalayeff <mickey@lucifier.net> To: June Carey <carey_june@hotmail.com> Cc: bugs@openbsd.org, bugs@freebsd.org Subject: Re: OpenBSD-2.9 random devices Message-ID: <200109231002.f8NA2Qhp010383@lucifier.net> In-Reply-To: <F28IlZ5cNww5jGpJtaO000031c8@hotmail.com> from June Carey at "Sep 22, 2001 06:52:16 pm"
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Making, drinking tea and reading an opus magnum from June Carey:
> Hi.
re
> In the OpenBSD-2.9 random(4) manual pages, it says: "The entropy
> pool is converted into output data using MD5"; /dev/srandom,
> /dev/urandom.
>
> I believe the implementation of these devices were "taken" from FreeBSD,
> hence the Cc:.
no, it was not.
> I suggest that the MD5 algorithm is removed and replaced with what I call
> the "XOR-fold-technique". As I'm sure you know, the one-time-pad cipher
> consists of a key-stream synchronously XOR'd with a data-stream.
>
> The "XOR-fold-technique" is the same thing, but applied to only one stream.
> For example, if you have a (secret) 16-byte quantity, you half it in size
> (8-bytes) and XOR one half with the other. The product is as secure as the
> one-time-pad cipher, i.e. it is a perfect one-way "hash".
and it does both at the moment, md5 and, then, fold it it in half.
> The replacement of MD5 with "XOR-fold" has the following advantages:
>
> (1) Guaranteed one-way function; MD5 is at best supposition.
> (2) Massive performance increase.
> (3) The algorithm automatically scales to the input size, whereas MD5
> produces a constant sized output (128-bits from memory ?)
>
>
> Disadvantages:
>
> None ?
yeah, right. and now think which qualities output
hash function should have and what your approach has?
cu
--
paranoic mickey (my employers have changed but, the name has remained)
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