# Thread: How do they prevent a blowup number?

1. ## How do they prevent a blowup number?

How can you program a rsa decoding 128 bit number? When I try and do it, my numbers just blow up. Can I ask for help.

2. Of course you can ask for help. Could you do it with a little bit more explaination though. I'm a little lost as to what you're trying to accomplish.

3. h3r3tic

I agree, what is this "blow up number"...............I am not aware of it in cryptography, only in CAD/photoediting etc.............it IS a mathematical concept, I just thought that they had gone and invented something else without telling me..................

Seems to happen quite often these days?

Can you show us an example mate?

4. The Numbers is about 646 digits long and I can't go any farther, so it is a blow out number. It is to big to obtain accurate calculations. So please tell me how I can program around this.

5. Short answer, if we are on the same page: Rewrite The RSA (Rivest, Shamir & Adleman) algorithm to calculate a predetermined normal end result and establish a blowup parameter. You will also need to plan for the Charmin Moment when an end result exceeds the blowup parameter. That’s the easy part if we consider that the normal end result will be only a real positive number. Now you will need to suck down some fermented fig squeezin’s like the old Egyptian Mathematicians did after they encountered the problem of finding the square root of a negative number. So distraught over their dilemma, they broke out the bottle. After becoming well lit, one of them asked the other, “What do we do now?” Another one responded, “Hell I don’t know, fake it?” And that’s what they did; they employed the imaginary number into functions. In that the imaginary number (i) is equal to the square root of –1.

Long answer: The RSA Algorithm was written to allow variable key lengths, thus the blow up numbers.

cheers

Edit: Forgot my favorite link on the RSA Algorithm: RSA

6. you need a class for the use of BIG integer Abstract data types. In C/C++ this would be a lib I persume, Java has the BigInt class aswell as BigFloat. I assume there is a C# class aswell, perhaps System.Maths.BigInteger or something along the lines of that.

if this fails, you might need to sit down and learn how to do funky odd maths in base 2, produce a class to simulate this and then store everything as a byte array.

7. Well poke me with a big stick!

Relyt you are spot on mate!......................it is to do with (i), and that is what I was thinking about, but in a quite different context

I was thinking fractal designs and just couldn't make the leap to cryptography.

http://www.fractaldesign.net/algor.htm

Thanks!

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