3DES (or AES or DES) on a micro for secure communications?

[blapcb]

I need to implement some type of embedded security over a serial link, like 3DES (or DES or AES), and really don't know where to start to look, so some pointers would be really helpful.

- Can this be implemented only in software? (code space?)
- Does anyone sell a library that can be used?
- Do the two units (which can be any two units) have to know the keys in advance?

Thanks!

 

[wek]

You can find a couple of block ciphers implemented in asm for AVR and '51 on http://www.efton.sk/crypt . Although these are considered weaker than AES/3DES (mainly due to shorter key, which is still longer than on plain DES), for many microcontroller-based application they are more than sufficient. That might give you at least a rough picture, perhaps.

Nevertheless, security is a much broader topic than just implementing a block cipher...

JW