I want simple encryption and decryption of password in C#. how to save the password in encrypted format in database and retrieve as original format by decryption, kindly anyone help with sample code

The question already has an intrinsic mistake — an idea to decrypt password. If you think about it, you will see that decryption of a password is never needed in authentication.

Nobody should know the password, even a person who can full access the site and the location where authentication data is stored. In fact, a password should never be stored anywhere. Is it possible? It is possible, but it is not simple — is is very simple.

There can be different ways to do it, I'll explain the simplest one: you use calculate a cryptographic hash function of a password and store it. This function cannot be inverted, so there is no decryption in principle. During authentication, the user (why is the only person who knows the original password which is never stored anywhere) types the password, it is immediately passed through a cryptographic hash function, and obtained hash is compared with the stored hash. As simple as that.

Please see http://en.wikipedia.org/wiki/Cryptographic_hash_function[^].

This article also explains the properties of such functions which make them suitable for security.

Now, it is very important not to use MD5. This function is found to be "broken" and hence unsafe. Please see http://en.wikipedia.org/wiki/MD5[^].

Instead, you can use one of the functions from the "SHA-2" family (stands for Secure Hash Algorithm). A set of these function is available in .NET. Please see:
http://en.wikipedia.org/wiki/SHA2[^],
http://msdn.microsoft.com/en-us/library/system.security.cryptography.hashalgorithm.aspx[^].

—SA

Refer This

Simple encrypting and decrypting data in C#[^]

Or u can use MD5

http://msdn.microsoft.com/en-us/library/system.security.cryptography.md5.aspx[^]

http://blog.brezovsky.net/en-text-2.html[^]