Christmas lectures last night.

stevemcol

Anyone else running the prime number finder??

A-Wing

Dam, I forgot that was on.
We wrote/ran a prime number finder on a Pentium PRO 200 when it was new about 12 years ago. Also wrote/ran a program to find pi to a really high decimal point.
The things you do when you are a bored geek teenager

Cypher

I always forget when these are on :mad:

Channel Five 19:15-20:00

I'll miss tonights as well anyone know if they will be repeated.

newfoundglory

I had a weird idea once. My "geeky" C background meant I was inspired to write a large prime number generator in PHP in order to implement the Diffie-Hellman key agreement protocol. This works best with very large prime numbers. The aim was to secure and encrypt PHP scripts using nothing but PHP across insecure and stateless http connections.

Then I got a job, and never had time to finish it. Ah well.

Anyway... was the prog good?

stevemcol

nfg

In last night's lecture, there was a reference to the importance of large prime numbers in cryptography.

Have a look here http://www.rigb.org/christmaslectures06/pdf/0_3_1.pdf for a bit of fun and maybe lend them some processor time!

A-Wing

newfoundglory wrote:

I had a weird idea once. My "geeky" C background meant I was inspired to write a large prime number generator in PHP in order to implement the Diffie-Hellman key agreement protocol. This works best with very large prime numbers. The aim was to secure and encrypt PHP scripts using nothing but PHP across insecure and stateless http connections.

Then I got a job, and never had time to finish it. Ah well.

Sure it would have been better to write the prime number generator in C as a module for PHP, it would probably give you a 300% speed boost against unoptimised PHP4 based code.

newfoundglory

Cheers.... check this out:

Lecture 4 The case of the uncrackable code

Broadcast 28th December 2006

7.15pm five

From the Caesar Cipher to the Da Vinci Code, people have been fascinated by secret messages. The mathematics of codes lets us to do everything from photographing the surface of Mars to shopping securely on eBay. Find out how prime numbers are now the key to codes which protect credit cards from internet hackers, and how, in the digital age, i-pods and digital TV are just a load of 0s and 1s.


^^ one to watch!

newfoundglory

A-Wing wrote:

Sure it would have been better to write the prime number generator in C as a module for PHP, it would probably give you a 300% speed boost against unoptimised PHP4 based code.

You would think so wouldnt you? It would definitely be faster - but imagine the headache you create for yourself. It becomes very unportable unless its written correctly.

C by its very nature is a very portable lanaguge across platforms. You would still have to compile the module for every platform you want to use it on. But the very nature of the module - the fact its dealing with very large numbers - you have to start constructing abstract data structures to handle them. Intel, PowerPC, SPARC, Itanium.... 32 and 64-bit.

Do-able, but more complex for true platform independence. Probably not worth it unless you need to generate a huge number of primes.

Cypher

for anyone interested last nights is on the newsgroups a.b.doc...

John_Gray

I was looking forward to the first Christmas Lecture and recorded it -- but I just had to turn it off because of the intense patronising of the lecturer. Surely it isn't necessary to have an explosion every time he wanted to make a point?

John

A-Wing

newfoundglory wrote:

You would think so wouldnt you? It would definitely be faster - but imagine the headache you create for yourself. It becomes very unportable unless its written correctly.

C by its very nature is a very portable lanaguge across platforms. You would still have to compile the module for every platform you want to use it on. But the very nature of the module - the fact its dealing with very large numbers - you have to start constructing abstract data structures to handle them. Intel, PowerPC, SPARC, Itanium.... 32 and 64-bit.

Do-able, but more complex for true platform independence. Probably not worth it unless you need to generate a huge number of primes.

Ah, indeed, sorry I was assuming you were creating for a unique implementation. But then if you were interested in optimisation for that kind of unique task you would probably use an optimised dedicated math processor anyway.