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From: Peter Fairbrother <peter@tsto.co.uk>
Newsgroups: sci.crypt
Subject: Re: What are the chances of this encrytion being broken?
Date: Sun, 23 Mar 2025 11:16:37 +0000
Organization: A noiseless patient Spider
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On 23/03/2025 04:14, hal@invalid.com wrote:
> What are the chances that the encrypted text in this message could be
> broken?

The chance that it could be broken? Not enough information to say with 
any accuracy. Might be easy, might be close to impossible. It's long 
enough that a huge quantum computer given a very long time to do it 
could in theory do it, so it's not totally absolutely impossible.

The chances that someone will actually bother to break it? Close to zero.

> No one knows what program made the file. 

Alice knows. So does Bob. So do their computers. Their software 
suppliers may have hints. Und so weiter.

We usually assume that the program/cipher is known because, if kept 
secret, if the secret is revealed once it is revealed for all instances 
(Kerckhoff's principle).

> It's 256 bit encryption.

But is it _good_ 256-bit encryption? If it's home-grown it isn't good 
(Schneier's law).

Then there is always lead pipe cryptanalysis...

https://xkcd.com/538/



Peter F