What is CRYPTOGRAPHY

Cryptography is the science or study of the techniques of secret writing, especially code and cipher systems.cryptography is now a core part of modern commerce, it is often regarded as a "black art".Today, most cryptography is digital, and the original text ("plaintext") is turned into a coded equivalent called "ciphertext" via an encryption algorithm. The ciphertext is decrypted at the receiving end and turned back into plaintext.Cryptography ensures message security over internet.

Types of Cryptography :-

1. Cryptographic checksums - Checksums help prevent undetected modification of information by encrypting the checksum in a way that makes the checksum unique.

2. Steganography - Steganography is actually the science of hiding information from people who would snoop on you. The difference between this and encryption is that the would-be snoopers may not be able to tell there's any hidden information in the first place.

3. Secret key cryptography - In secret key cryptography a single key is used for both encryption and decryption.A sender uses the key to encrypt the plain text and sends cipher key to the reciever.The reciever applies the same key

to recover the plain text.

4. Hash functions - Hash functions are also called message digests , they are algorithms without any key.A fixed length hash value is computed based upon the plain text to be recovered.Hash functions are used to provide a digital fingerprint of a file's contents to ensure that if the file has been altered by virus