crypting numbers

[lastrezort]

Here's one for yall,

I'm in search of an algo that will take a 3 digit number and encrypt it to give ANOTHER DIFFERENT 3 digit number... something very hard to crack would also be nice... Can it be done and can it be done with other number sizes (like for an 8 digit number for example which I'm also looking for)?

Thanks!

[qball]

I'm in search of an algo that will take a 3 digit number and encrypt it to give ANOTHER DIFFERENT 3 digit number... something very hard to crack would also be nice...


Many ways to do, very easy.

Hard to crack? why bother? with a 3 digit number, only 1000 possibilities, thus will crack in less than 1001 tries.

why bother?

[lastrezort]

I know it ain't hard to do but I need either something complex so it's a bit harder to decypher or either something already made so I can see the basics of things... I'm not much of a programmer so...

[bassman]

See if this helps:
http://www.netalive.org/codersguild/posts/151.shtml

A paper about the TEA (source code available):
http://vader.brad.ac.uk/tea/tea.shtml

Some philosophy:
http://www.geocities.com/SoHo/Cafe/2260/crypto.html

[elroy]

Encryption is an extremely complicated subject. Yes you can encrypt a 3 digit number but to do so securely the key would have to be much longer than 3 digits. This is why websites with passwords ask for a password of 5 or 6 or 7 characters. Even this is not secure by any means. PGP is considered to be just about the most secure encryption program available and the keys for it are an entire paragraph of numbers, letters etc. Can you provide some more details on what you are wanting to do?

[bassman]

Originally posted by elroy
This is why websites with passwords ask for a password of 5 or 6 or 7 characters.
It was my belief that that was mainly to prevent brute force attacks

[lastrezort]

Here's what I need to do;

Ive got a series of numbers in a file. each number is 8 digit long.

Here's the range;

01001001 to 99999999
OR
I can put them in three groups;
01, 001 and 001

It's like a social security number where 01 = the date, 001 = something else, blah blah blah...

each number (8 digits) serves as an ID to something else (these are IDs and there are other fields attached to these IDs but I don't want to change these)

The IDs are NUMERAL, not alphanumeral.

How can I encrypt these while knowing I can't change the nature of the ID (they have to stay numerals)?

[elroy]

I'm trying to follow along: would an encryption program with a numerical password work for you?
Seems to me you want to encrypt the 8 digits into 8 different digits. While possible this would not be secure. What level of security are you seeking? Who do you want to prevent from accessing this info? A person would one level to keep the wife out of his porno while the CIA would use a different level to protect the names of spies in foreign countries.

[lastrezort]

I'm sending a file with confidential numbers (that 8 digit number) but it's in a text file. I have to pass it through other people but only some have the rights to see those numbers... The others don't have the right to see those numbers so I need some kind of script that will change them to another number but I also need a script that will put them back to normal... The first step is getting that algo that'll convert the important number to something that is there but isn't relevant to the rest of the other fields...

[qball]

Ive got a series of numbers in a file. each number is 8 digit long.
Here's the range;
01001001 to 99999999


what happened to:

I'm in search of an algo that will take a 3 digit number and encrypt it to give ANOTHER DIFFERENT 3 digit number...

elroy, is speaking 'crypting'...

[lastrezort]

Well, there are 2 ways I can do it... The first one is by crypting the whole number...

But the number is composed of 3 numbers put together (01, 001 and 001 make 01001001)

[qball]

Well, there are 2 ways I can do it... The first one is by crypting the whole number...
But the number is composed of 3 numbers put together


Your missing the 'crypting' part/jobber. As in:

111
crypted is:
67_

if one gives you '67_', what does one get back?

[frnkzks]

I suggest a shift-3 cypher. Caesar used it with great success.