[Cryptography] A software for combining text files to obtain high quality pseudo-random sequences in practice

[Sandy Harris]

mok-kong shen <mok-kong.shen at t-online.de> wrote:

> There are plenty of other schemes for obtaining high quality pseudo-random
> sequences in practice, e.g. AES in counter mode. However our scheme seems to
> be much simpler both in the underlying logic (understandability) and in
> implementation and is thus a viable alternative ...

I do not think it is viable, because it is not random; it depends
entirely on the input text. One article puts total size of the
web at 1.2 petabytes
http://www.sciencefocus.com/qa/how-many-terabytes-data-are-internet

Ignoring the facts that much of that is graphics, sound & video,
and another bunch is in languages other than English.
so your scheme might not work, and there's a whole lot
of duplication ...

That's 2^50 bytes so there are only 2^50 places to start
your hash or other algorithm. If you use local text only,
you might get 2^45 bytes (32 terabytes) or some such
on a big RAID array with current technology.

This is not nearly enough for any serious application,
& you still need a 2^45 or 2^50-bit seed from a true
RNG to choose a random starting point or it does
not work at all.

You are far better off using AES-CTR which has
far lower overheads than your data access
would require, and can take a larger key, 128
bits to initialise the counter then another 128,
192 or 256 for the actual key.



You can choose a stopping
point too, and maybe use some local non-web text as
well so it looks like you might get up to 2^64 or a bit
more possible different outputs.