What is cryptography ?
- Cryptography is an art of converting the plain text into unintelligible format (Cipher text ).
- On the receiver side that cipher text is converted into plain text.
- Cryptography mainly aims at privacy and integrity.
- Cryptography is not latest technique, it has formed thousand of years ago. But they uses some symbols to denote plain text message.
- Plain text : This is actual message sender wants to send to receiver.
- Cipher text : This is unintelligible text and normal person cannot understand this.
- Encryption : The process if converting cipher text into plain text is called encryption.
- Decryption : The process of converting cipher text into plain text is called decryption.
- Cryptanalysis : The study of understanding how crypto algorithm works and finding weaknesses is called cryptanalysis.
- Cryptanalyst : The person who does cryptanalysis is called is called cryptanalyst.
- Substitution cipher : These cipher simply replace plain text characters with some special characters.
- Block cipher : These ciphers operates on some block of bits.
- Symetric cipher: Same key used at the encryption and private key is used for decryption.
- Asymetric cipher : Pubic key is used for encryption and private key is used for decryption.
- Digital certificate : These certificates are used to establish a secure connection between sender and receiver. (e.g - SSL certificate )