Re: to sig or not to sig?

From: pbs (pnews_at_lomarline.freeserve.co.uk)
Date: 10/05/03


Date: Sun, 05 Oct 2003 12:04:10 +1300

Alan Connor wrote:
[snip]
> I was hoping for some intelligent feedback. If I wanted to experience the
> taunting of ill-mannered children, I would go to the nearest public
> school. Instead, I chose the Usenet and am surprised to discover that so
> many parents don't monitor their children's computer activities.

"Everything in common but language". I presume you mean state school.
Where I come from public schools are exclusive private schools and cost
their parents about about $30,000 a year. That is not to say of course
that the manners of their children are any better than at a state
school.

> Anyway, if there are any mature and mentally competent adults out there,
> it is my contention that it is very likely that the top levels of government,
> business, and the military have access to computers that make the best
> publicly available ones look like Gameboys.
>
> You just can't rely on encryption strategies that rely solely on choices
> made by software. There must be elements that only the human mind can
> translate.
>
>
> Here's the system myself and a few friends use:
>
> If I want to communicate privately with someone, I run a little script
> that puts out a randomly ordered list of 77 2-digit numbers between 00 and
> 99. I get them a copy of it using any medium except the internet and except my
> own phone.

How do you know that they are random and not pseudorandom?

You are using a single-key cypher. And you have all the well known
problems of how to disseminate the key. If you have a secure channel for
exchanging keys, then why do you need cryptography, just send the
information that way? The whole point of PGP and other similar
public/private key pairs is that you can send the public key over the
same channels as the encrypted message without the danger of the
secret/private key being exposed.

[snip your coding ideas (we had better keep them secret)]

I think you should read a little about how the chaps at Bletchley Park
broke enigma. I think you would be amazed at how ingenious they were
at breaking codes.

Here is a piece of text from the document which should accompany PGP
written in 1994 the inventor of PGP Philip Zimmermann:
:
: When I was in college in the early seventies, I devised what I
: believed was a brilliant encryption scheme. A simple pseudorandom
: number stream was added to the plaintext stream to create
: ciphertext. This would seemingly thwart any frequency analysis of
: the ciphertext, and would be uncrackable even to the most resourceful
: Government intelligence agencies. I felt so smug about my
: achievement. So cock-sure.
:
: Years later, I discovered this same scheme in several introductory
: cryptography texts and tutorial papers. How nice. Other
: cryptographers had thought of the same scheme. Unfortunately, the
: scheme was presented as a simple homework assignment on how to use
: elementary cryptanalytic techniques to trivially crack it. So much
: for my brilliant scheme.
:
: From this humbling experience I learned how easy it is to fall into a
: false sense of security when devising an encryption algorithm. Most
: people don't realize how fiendishly difficult it is to devise an
: encryption algorithm that can withstand a prolonged and determined
: attack by a resourceful opponent. Many mainstream software engineers
: have developed equally naive encryption schemes (often even the very
: same encryption scheme), and some of them have been incorporated into



Relevant Pages

  • Re: Young Leader Training
    ... > I have heard of a school trying to get pupils to start the DofE Gold 10 ... The programme (the DofE prefers to say programme not scheme nowadays) ... > of Young Leader Yellow Cards too - you'll need them from module A. ...
    (uk.rec.scouting)
  • [long] C code of PEARL1, a block encryption algorithm emphasising simplicity
    ... (cf. "A plead for simple encryption ... It uses a combined PRNG (cf. "A simple scheme ... // allocates 64 bits to unsigned long int. ...
    (sci.crypt)
  • Major Step Ahead for Cryptography
    ... Nigel Smart, Professor of Cryptology in the Department of Computer ... Major Step Ahead for Cryptography ... they are given an encryption of the two numbers but not ... "Our scheme allows for computations to be performed on encrypted data, ...
    (sci.military.naval)
  • Re: ISA Already Going Awry?
    ... The government is to look again at how a new vetting system for those ... to give friends' children "a lift to school or to Cubs". ... Mr Balls said the scheme had been introduced via legislation in parliament, ... Roger Singleton "to check the government has drawn the line in the right ...
    (uk.rec.scouting)
  • Re: "Rule 30" CA encryption implementation
    ... I agree with the contention that intense scrutiny is required to ... determine the soundness of an encryption scheme. ... Can you suggest a better place to give a working encryption program ... other than brute-force password testing. ...
    (sci.crypt)