J2ME Encryption Algorithm

Question

I'm trying to develop my own encryption algorithm for J2ME mobile application with MIDP2.0.
But I don't have any experience in encryption algorithm, Guys please give ideas for me.

I would like to encrypt document and I need to maintain that document in resource directory, Thats why I need encryption from hacking others.

Answer 1

Don't. Crypto is highly specialised, and the smallest mistake can result in a weak cypher. There are plenty of good crypto algorithms out there, such as AES, Salsa20 and others. Use one of them. That also saves you the trouble of writing your own code since there are libraries available.

Read Bruce Schneier on amateur cryptography: Memo to the Amateur Cipher Designer and when you have read it, drop any thoughts of designing your own cypher and use one of the standard cyphers. AES-CTR + HMAC or AES-GCM are my personal preferences, YMMV.

Answer 2

a) I completely agree with rossum. Don't write your own encryption. It's really bad idea (one wrong step and it won't be secure at all).

b) I believe there is Bouncy castle encryption library (http://www.bouncycastle.org/latest_releases.html) which supports J2ME.

c) I recommend to read following article which gives information and examples for encryption/decryption of data on j2me (http://www.ibm.com/developerworks/java/tutorials/wi-encrypt/index.html)