Cryptography

Encryption is process of encoding information in a way that only authorized people can read it by decrypting. Encryption generates ciphertext that can be only be read if decrypted. 

Symmetric key

encryption and decryption keys are the same. Therefore the key needs to be shared between all parties.

Asymmetric (public) key cryptography

The encryption key is published for anyone to use and encrypt message. However only the receiving party has access to decryption key that enables message to be read. Therefore one key is public and  the other is private. 

Cryptography in .NET Framework

Following is how .NET has organized its classes

• Algorithm type class : SymmetricAlgorithm, AsymmetricAlgorithm or HashAlgorithm. This level is abstract
• Algorithm class which inherits from type class : Aes, RC2 etc. This level is also abstract
• Implementation level : AesManaged, RC2CryptoServiceProvider. This level is fully implemented

For more information see .NET framework Cryptography model.

What is X.509 Digital Certification

http://msdn.microsoft.com/en-us/library/windows/desktop/aa388452%28v=vs.85%29.aspx

What is SSL (Security Socket Layer)

SSL is a standard security technology for establishing an encrypted link between server and client.

key vs cipher vs hash

Resources

http://stackoverflow.com/questions/tagged/cryptography

http://stackoverflow.com/questions/tagged/encryption
http://security.stackexchange.com/questions/7219/asymmetric-vs-symmetric-encryption
http://www.codeproject.com/Articles/448719/Cryptography-Asymmetric-Encryption-by-using-Asymme
https://www.digicert.com/ssl.htm
http://msdn.microsoft.com/en-us/library/windows/desktop/aa380255%28v=vs.85%29.aspx
http://www.devx.com/dbzone/Article/29232/0/page/3 (Image credits)
https://msdn.microsoft.com/en-us/library/ff647097.aspx