It is the art or science to design ciphers, i.e. a message written in secret code. It is the key enabling technology that is used to protect distributed systems. The Process of breaking these secret codes is called cryptanalysis. Input text that is provided for encryption is called plaintext and the encrypted text so obtained as output is called cipher text.
There are three main techniques that are used to generate strong cipher:
1) Block Cipher: This cipher converts block of plaintext to cipher text in spite of single or individual character. DES (Data Encryption Standard) and AES (Advance Encryption Standard), Playfair are some examples which are based on block ciphers.
2) Stream Cipher: Stream Cipher generates a random long stream of keys that are combined with plaintext bit by bit or character by character. In a stream cipher, cipher text is created based on a hidden internal state which changes as the cipher operates. That internal state is initially set up using the secret key material. Example: The Vigenère Cipher.
3) Cryptographic Hash Functions: In this Cryptography technique message of any length is taken as input and output is generated as short fixed length hash that are than used in digital signatures. MD4 and MD5 are two examples that are based on hash functions
There are three main techniques that are used to generate strong cipher:
1) Block Cipher: This cipher converts block of plaintext to cipher text in spite of single or individual character. DES (Data Encryption Standard) and AES (Advance Encryption Standard), Playfair are some examples which are based on block ciphers.
2) Stream Cipher: Stream Cipher generates a random long stream of keys that are combined with plaintext bit by bit or character by character. In a stream cipher, cipher text is created based on a hidden internal state which changes as the cipher operates. That internal state is initially set up using the secret key material. Example: The Vigenère Cipher.
3) Cryptographic Hash Functions: In this Cryptography technique message of any length is taken as input and output is generated as short fixed length hash that are than used in digital signatures. MD4 and MD5 are two examples that are based on hash functions
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