What is a basic way to encrypt/decrypt a string?

faydra92

So that i could even send encrypted/decrypted data from windows (vb app) to the php script?

md5 or something wont work cause i wont be able to en/decrypt it outside php

basically i want to be able to send encrypted data from a wnidows app to a script, and be able to send encrypted data from the php script to windows, and decrypt the data as neccessary..

any idea?

Weedpacket

If you don't want to spring for an SSL license, and you want decent encryption (as opposed to kids in treehouses playing with secret codes), then probably the most reliable bet would be to use the [man]mcrypt[/man] functions in some way; there are bound to be VB apps/ ActiveX controls/etc., available for download somewhere that will provide the corresponding client-side functionality for at least some of the algorithms the mcrypt library provides (3DES is a fairly well-established algorithm, for example).

faydra92

but what i dont get is if these encryption methods are so established, and people can crypt and decrypt strings using the same method, then whos to say that anyone else that gets access to a string encrypted with mcrypt cant just decrypt it himself?

but that doesnt matter anyway - i cant find any functions for vb

does anyone have a very simple function to encrypt strings? like take each character in a string and add a value to it or something?

laserlight

Well, that person would need to know your key to decrypt it.

I suggest that you read this FAQ:
http://www.faqs.org/faqs/cryptography-faq/

superwormy

does anyone have a very simple function to encrypt strings? like take each character in a string and add a value to it or something?

LOL that is HARDLY encryption :-)
Go read up on how key based encryption works, public / private key pairs.

Weedpacket

Originally posted by faydra92
but that doesnt matter anyway - i cant find any functions for vb

What about Java? Or C for that matter? After all, VB is limited to Windows/IE.

faydra92

i just want to make the data unreadable.. that is, if someone uses a packet sniffer and sees data going out/in, i dont want him to be able to easily get what is being sent..

i just need a very basic method to make something unreadable, so once its passed, the php script (or vb app) can decrypt it again

and vb is my only option, as the app will be for windows

TruckStuff

i just want to make the data unreadable.. that is, if someone uses a packet sniffer and sees data going out/in, i dont want him to be able to easily get what is being sent..

Number one rule of data security: if a peice of data is worth encrypting, its worth encrypting well. Simply adding something to the string is only going to make it slightly more difficult for someone to read.

If you are really concerned about the security of your data, read up on real encryption algorythms. Otherwise, don't bother encrypting it.

Weedpacket

Originally posted by faydra92
and vb is my only option, as the app will be for windows

Don't see why that makes it your only option. It's not like VB is the only language you can use for Windows programming.

What you're describing is what SSL was invented for.

faydra92

Originally posted by Weedpacket
Don't see why that makes it your only option. It's not like VB is the only language you can use for Windows programming.

What you're describing is what SSL was invented for.

cause i dont have time to code a simple program in c++ or something in one month when i can do it in 2 days in vb..

its really not that important data, basically i just need vb to retrive data like http links from the php server

i dont need major encrypting, because then it would be hard to port to the other language..

please does anyone have any simple encryption function?

faydra92

bump

laserlight

If it's not important, dont waste processor cycles encrypting it.

If it's important, dont risk it by using weak encryption.

You want "encryption" that is trivial to break?
Just use [man]str_rot13/man, or [man]strrev/man, but it should be plain that you're just wasting time.