Possible to recreate GPG using pen and paper?

Harry Rickards hrickards at l33tmyst.com
Sat Jun 6 10:42:18 CEST 2009

Hash: SHA1

On 06/05/09 22:16, J Simoes wrote:
> It's possible BUT not really :-)
> The more time consuming part is finding the 2 prime numbers. If this
> is just an exercise, is easy. But for really applications they are
> very hard to find because you need  LARGE prime mumbers.
> If you do not work enough you end up with 2 numbers that probably are
> prime, but you have same probability that they are not. If  they are
> not prime your cryptographie would be very weak.
> The most work you put on the process the more sure you are that you
> get "true" primes. Is not possible to be sure, but you can be pretty
> sure they are. But that means a lot of work.
> José Simões
> On Fri, Jun 5, 2009 at 07:52, Harry Rickards<hrickards at l33tmyst.com> wrote:
>> Would it be possible to do the same job that GPG does (using all the same
>> algorithms) simply using a pen and paper? You can do simple public key
>> crypto with RSA, by choosing two primes and doing a multitude of stuff with
>> them. I understand that it will take a while to actually encrypt/decrypt
>> something, and you'll need a calculator as well, but it would be fun to try
>> all the same.
>> Thanks
>> Harry Rickards
>> P.S Not signed as I'm currently using an iPhone.
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>> Gnupg-users mailing list
>> Gnupg-users at gnupg.org
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This is just for fun, as well as a bit of maths homework, so the numbers
won't have to be too big. Just out of interest, does GPG have it's own
method for multiplying/dividing really long numbers (I'm having to do
the maths in python, which gives an integer, and then work out the

- -- 
Many thanks
Harry Rickards (GPG Key ID:646ED06A)

Version: 3.1
GAT/GCM/GCS/GCC/GIT/GM d? s: a? C++++ UL++++ P- L+++ E--- W+++ N o K+
w--- O- M- V- PS+  PE Y+ PGP++ t 5 X R tv-- b+++ DI D---- G e* h! !r y?
- ------END GEEK CODE BLOCK------
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/


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