Security

 Cryptography  Basic Terminology  Encryption: cipher plain text and make it into unreadable message. cf) cipher is done by using encryption algorithm and key (which is unique for every cipher)  Decryption: reverse of encryption. Symmetric cryptography  Same key is used for encryption and decryption. Encryption algorithms for Symmetric cryptography : DES, RC4, AES  Asymmetric cryptography  Different keys are used for encryption and decryption.  Utilizes computational difficulty of large numbers.  But how do we know who sent the message ?? Anyone can peek at public key and anyone can argue that the message was from him. This is where digital signature comes into play.  Algorithms used in asymmetric cryptography  RSA(Rivest-Shamir-Adleman)  One of first practical asymmetric cryptography system. RSA system specifies mechanis