Encryption/Decryption of Data

Hello Programmers,
I am working on a small project which includes Encryption and decryption.
In my project I need to Encrypt the data while sending it to Server from Client and then Decrypt it back on the Server side.!!
So, I need:
1) Server-client connection
2)Sending of encrypted data/file from Client and then to decrypt it on Server side.
3) If possible , I need to do retrieve the data while sending from Client as a third party.
So could I get any help?
Please help if possible and suggest me some ways to do it.!
I am looking forward to get your replies.

Durgesh Kumar wrote:
3) If possible , I need to do retrieve the data while sending from Client as a third party.

Do you mean you actually want to be the man-in-the-middle? It is normal to try to prevent this!

If you don't actually want to allow man-in-the-middle then JSSE will do what you want and there are many tutorials on the web; Google will find them. Otherwise then a good starting point is "Beginning Cryptography with Java" by David Hook published by Wrox.

Richard Tookey wrote:

Do you mean you actually want to be the man-in-the-middle? It is normal to try to prevent this!

Yes, this would be better if I can show this by trying to be the man-in-the-middle. And I need to do all the previously mentioned things too.!!

Durgesh Kumar wrote:

Richard Tookey wrote:

Do you mean you actually want to be the man-in-the-middle? It is normal to try to prevent this!

Yes, this would be better if I can show this by trying to be the man-in-the-middle. And I need to do all the previously mentioned things too.!!

It does sound like you need JSSE which does the other things and is designed to make a man-in-the-middle attack difficult. Google is your friend.

If you're only concerned about protecting the data in transit, why not send it over HTTPS, and save yourself all the hassle of applying crypto explicitly?

Ulf Dittmer wrote:If you're only concerned about protecting the data in transit, why not send it over HTTPS, and save yourself all the hassle of applying crypto explicitly?

I need to show the whole process(1.Encryption of the file on client side. 2. Sending the encrypted data to the server side. 3. Decrypting the encrypted data on Server side.) by using some algorithms(AES, DES) on two different computers.

Richard Tookey wrote:

It does sound like you need JSSE which does the other things and is designed to make a man-in-the-middle attack difficult. Google is your friend.

I have to use some encryption algorithms, like AES, DES, RSA.!!!

Durgesh Kumar wrote:

Richard Tookey wrote:

It does sound like you need JSSE which does the other things and is designed to make a man-in-the-middle attack difficult. Google is your friend.

I have to use some encryption algorithms, like AES, DES, RSA.!!!

Then you need to study the JCE. The 'Hook' book is a good starting point but there are many tutorials online. Again, Google is your friend.

Oh, so this isn't a practical problem, but more like an academic exercise?