Large Integer module (LargeNum)

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Submitted on: 1/15/2004 12:03:57 PM
By: Acid Juice
Level: Beginner
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By 1 Users
Compatibility:VB 6.0

Users have accessed this code 470 times.

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This module allows to perform basic computations on positive and negative Large Integer Numbers up to 32,767 digits: add, substract, multiply, devide, compare and exponential functions. Code is highly commented, sample LargeNum calculator included. Feedback is highly appreciated: main purpose here would be to considerably speed up the process, and even if code is maximised i'm looking forward to your input. For others who can't provide direct input, feel free to download, voting recommended even though not compulsory :) Cheers to you all, ACiD.

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Other User Comments

1/15/2004 12:42:25 PM:Paul Guerra

What about floating-point numbers?

1/15/2004 12:52:38 PM:Acid Juice

hi paul,
kept of having issues on 
exactitude of numbers, as decimals were 
up to a point approximated. however if 
you do have examples of this i'm really 
interested, large numbers and 
crittography is getting me in the way 
and will soon be posting some VB code 
on Miller-Rabin, Fermat tests and Large 
Prime Numbers generation.
Of course, 
fastest Large Number computation more 
than welcomed.

1/15/2004 3:31:19 PM:korejwa

First, congratulations on successfully 
coding a very difficult and usefull 
project.  A Large Integer Math Library 
is one of those "holy grails" for VB 
coders.  I've tried to create one 
myself, but it's much more difficult 
than anyone knows!
If you want to 
speed up and optimize, you should store 
numbers and perform operations on 256 
Radix Byte Arrays instead of Strings.  
This is as optimized and fast as you 
can get.
I recommend looking at the 
last chapter in "Numerical Recepes in 
C" for some important concepts.  Also, 
look at Ron van Tilburg's "Variable 
Length Integer Maths" (code ID:34747) 
here on PSC.

1/15/2004 5:07:58 PM:Acid Juice

hi korejwa, and thank you for your 
support and input. i definitely will 
look into what you have suggested 
asap.
as i reported in my previous 
post, i am developing a full RSA 
encryption program. currently 
everything works great, however it just 
takes too long to create 128-bit keys, 
and when you think that RSA is 
considered secure with more than 
512-bit keys you can see why i need to 
speed up this module to increase 
algorithm treatment.
i will be 
posting these projects here soon, asap 
i'm able to improve some speed. i'm 
sure more than one person is interested 
in LARGE NUMBERS PRIME GENERATION, and 
all the encryption which is behind (too 
many examples of 8-bit keys around 
:)).
keep up the good work, and 
again, thanks.
ACiD.

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