News:

MASM32 SDK Description, downloads and other helpful links
MASM32.com New Forum Link
masmforum WebSite

Extended precision arithmetic information

Started by Proto, December 30, 2007, 10:56:04 AM

Previous topic - Next topic

Proto

I've been looking for good algorithms for extended precision multiplication/division/modulo etc. for cryptography purposes. There doesn't seem to be much on these forums (or I'm searching for the wrong thing?) so I was wondering if someone could give me a push in the right direction. Links / book names would help enormously.

Thanks in advance.

GregL

I assume by "extended precision" you are talking about using REAL10 floating-point variables. If you want to work with extended precision, you'll need to use the FPU. Simply FPU is a great tutorial and reference. The FPULIB library is on the same page.


dsouza123

It is large integer math that is used in cryptographic algorithms, instead of 32 bit integer values
they are 512, 1024 or 2048 bit numbers.

Names are Richard Crandall and Carl Pomerance, others Hans Riesel, Daniel J. Bernstein.

There have been quite a few crytography algorithms posted in the MASM32 forums.

Examples MD5, DES, SHA-512.

donkey

There are a quite a few big number libraries out there, a quick google would probably get you what you need.
"Ahhh, what an awful dream. Ones and zeroes everywhere...[shudder] and I thought I saw a two." -- Bender
"It was just a dream, Bender. There's no such thing as two". -- Fry
-- Futurama

Donkey's Stable

GregL

Yeah, I thought he may have meant large integer math. To me "extended precision" means a 10-byte floating-point variable.

The only large integer library I have used is GMP, I found a compiled DLL and LIB here, I used it in a C program. It wouldn't be difficult to use in assembly.