Security plays a significant role in our day to day life. So far software applications are concerned, security of data is required for authentication and for several validations. Normally while developing the applications, we use the concept of cryptography for password encryption and decryption. Some applications require more security, so they go for high end security system like trusted security certificates. The security mainly focuses on the integrity of the data at the several ends.

Technicalities For data security Java Cryptography provides a suitable framework to implement several kinds of cryptography. However there are basically two types of cryptography. Once is Symmetric Cryptography and Asymmetric Cryptography. When both the ends communicate the secured data with a common key for encryption and decryption, it is called the Symmetric Cryptography. In this case a shared key is used by both the parties to encrypt and decrypt the data. However there is a problem relating to exchange of key for symmetric cryptography. To overcome this problem java provides another approach for the cryptography called Asymmetric Cryptography. In case of Asymmetric cryptography, there will be two keys unlike one key in case of symmetric cryptography. One key is called Private key and other is called Public key. These two keys are generated together and can be used for encryption and decryption. In this case the Public key is used by anyone who wishes to communicate securely with the owner of the Private key. The Private key is used by the main owner and the owner gives the Public key so that they can decrypt the data. In this article I will give you the example on Asymmetric cryptography. You can find more tutorials and concept on Sunâ€™s JCE(Java Cryptography Extension). In my next article, I will provide you the example on Symmetric cryptography.

### Complete Example

This example is only meant for learning and not for any specific use. You can take the piece of code to test in your system to learn the above concept.

The following class is used to create the Public key and Private key. This class contains generic methods to generate the Public and Private key. If you run the testharness class, you will find the two files called â€œPublic.keyâ€ and â€œPrivate.keyâ€. Please go through the java docs mentioned in the methods.