Pseudo Random Function for J2ME

[Koot Jart]

Hi!

I think this is really tough question, but lets try.

I'm implementing small software in J2ME environment. Part of that software is to encrypt a small txt-file using a password based encryption. I'm using SATSA (Security And Trusted Services API, JSR177) for actual encryption. However, I need to generate a key for that encryption process. Key generation must be done using so called "slow funcktion". I have decided to use PBKDF2 algorithm for that purpose (see: http://www.ietf.org/rfc/rfc2898.txt)

At the moment I have started to implement PBKDF2 for J2ME. I can do everything else, but I have a problem creating PRF (Pseudo Random Function), that is used in key generation process. I can' use Mac and SecretKeySpec classes, that are part of JavaSE:

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

Those classes are not in J2ME unfortunately.

Could somebody give me any hint, how I could create my own PRF for J2ME? Which algorithm to use? Are there anything ready for J2ME.

Br
Koot

[Tim Holloway]

Donald Knuth defines a PRF algorithm in his seminal work "The Art of Computer Programming". Basically, it chops the preceeding number in the series into 2 parts, then merges the parts using simple arithmetic.

You should be able to google for Random Number Generator Algorithm and find lots of code.