Implimenting blowfish and RC5 in java

Question

Hi,
I wanted to develop code in java for a cryptographic algorithms like Blowfish,RC5. I searched on the internet too but I got to know that Blowfish has ready made methods available. So writing own methods is like 'reinventing wheel' so is the same case with 'RC5' too?
If this is the case, can you please suggest me some algorithms of cryptography for which code can be developed within the duration of 2 months using 2 people having average knowledge about 'Java'?

Answer 1

Starting out any cryptography project without knowing a lot about the idiosyncrasies of the language you are working with and the cryptographic algorithms involved is a really, really bad idea. If you are just doing it to learn, then why not just go ahead and reinvent the wheel? If you actually expect it to be secure, you really should use a pre-existing, well-tested implementation, or you should carefully investigate the algorithmic approaches involved and the language-based security issues involved.

There is nothing inherently labor-intensive about the implementation of any of these algorithms - they tend to have clear descriptions published. It would be entirely possible for you to do a not-necessarily-cryptographically-secure implementation of RC5, Blowfish, AES, RSA or just about anything else commonly used within 2 months (although I'd put the real figure somewhere nearer 2 days if you're just messing around for learning/fun).

Answer 2

Visit BouncyCastle.org. They provide a full and open source JCE / JCA crypto API for Java and C#. There are also other APIs for PGP for example. Unpinning these APIs are implementations of virtually every common cipher and digest algorithm. Documentation is a bit light (especially the PGP implementation) but it is a very well known and used crypto package.

Answer 3

There have recently been several questions here relating to format preserving encryption. I tried to find an implementation of FFX (an attempt to standardize Feistel-network based FPE), but failed to find any.

So if you are looking for an example of a useful cryptographic algorithm for which there is no (easily findable) implementation on the net, that is one option.

You might want to restrict yourself to FFX-A2 and/or FFX-A10.