How do I write an encryption program?

[Apollyon]

Hi guys, it's Apollyon here, and I was wondering, how do I write an encryption program? Nothing to simple, just one that would encrypt, decrypt, and shred files and emails. Any info?

[Ejaz]

Have a look at CryptoAPI & Visual C++ Encryption Examples.

[Apollyon]

Thanks, but, could you give me like some source code, an algorithm, stuff like that, 'cause I'm really trying to write a brand new algorithm.

[Bob Davis]

Then what is your question? If you're making up the algorithm, why would you need source code for other algorithms?

Try not to ask such general questions like "How do I write an xxxxxxxxxx program?". Investigate for yourself; Google can work wonders.

[Apollyon]

Sorry, didn't phrase that question correctly. I was really trying to say, can you give me some source code for Alogorithms like AES, 3DES,Rijndael.

[vcstarter]

If you want to understand incription basic, it is very simple. You simnply xor our byte with some value. For instance if you have have a text file, you can convert the characters to ascii format then xor them with a value.

[kasracer]

Start with something basic and work from there. Why don't you try a simple xor encryption and decryption method (as vcstarter mentioned)?

You shouldn't need the actual source code for any actual encryption methods as long as it's well enough documented in how it works so you can easily translate it into code. I had a link to a site that explained how several different algorithms worked but I no longer have the link. I'll try to find it or maybe someone can post a good site like that.

[Apollyon]

Actually, I'd like to combine AES and 3DES to create something like 3AES or something

[Thingol]

There are three famous C and C++ encryption libraries freely available:

OpenSSL - http://www.openssl.org - used in every web server (except Microsoft IIS and Netscape Web Server) you know.

CryptLib - http://www.cryptlib.orion.co.nz - it's easy to use and fool-proof.

Crypto++ - http://www.eskimo.com/~weidai/cryptlib.html - It's a C++ library, but it's not easy to use because uses a lot of templated code