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Thread ID: 86034 2007-12-31 23:21:00 Challenge to break my code andrew93 (249) PC World Chat
Post ID Timestamp Content User
626394 2008-05-31 01:36:00 Hi

I'm not sure I follow 100% - what do you mean by sub-exponential? If you are referring to the number of tests required not growing exponentially then there are ways and means of reducing the test population.

Following is the output from a programme I wrote last year:



I realise the number that I tried to factor is quite small, but I think you'll find the two factors are prime numbers. When I said 'albeit very slowly' - I meant two things - first up is that I haven't explored this for a while and secondly, from memory my routines start to slow considerably once you get into the trillions.

Andrew

You should realise that since it is exponentially difficult to compute prime factors, as the number gets larger, it gets exponentially more hard to factorise it: en.wikipedia.org There are probabilistic algorithms to determine the likely hood of a very large number being prime (a 'pseudo prime'), such as the Rabin-Miller test, and more recently a deterministic algorithm called AKS. Neither of these will help you factor primes. In fact, the company behind RSA had a prime factorisation contest giving away very nice sums of money to those who could factor 100 or 200 digit primes.
DangerousDave (697)
626395 2008-05-31 03:22:00 Understood. I had identified the issue of ever-increasing combinations (it was the terminology that confused me). I also found and had a (retrospective) go at the RSA challenge. With that in mind, there are still ways of reducing the testing required and I will keep exploring various avenues. I realise the implications of being able to do this so won't give up too easily. I just need to get my hands on a quantum computer......:)

In any case it looks like RSA uses pseudo primes (or probable primes).

Andrew
andrew93 (249)
626396 2008-06-04 23:32:00 Any chance of you being able to post the algorithm / method you used to encrypt this with? It's now been 5 months since the start of the challenge; there's no way it takes 5 months to lodge a patent application.Bump? Erayd (23)
626397 2008-06-04 23:37:00 I will be posting a working version of the software sometime soon - once I sufficiently cobble it to avoid issues with restricted exports.

Andrew
andrew93 (249)
626398 2008-06-04 23:56:00 Ah - which country do you live in? Erayd (23)
626399 2008-07-01 01:00:00 I will be posting a working version of the software sometime soon - once I sufficiently cobble it to avoid issues with restricted exports.

Andrew

Well? Where do I download it?
Erayd (23)
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