Hello Steemit friends!!

In my previous post,you knew a little about encryption and decryption technique.Today,I am going to tell you about Ciphers and their types.

CIPHER

A cipher is an algorithm for performing encryption and decryption.The operation of cipher depends upon the special information called key.Without knowledge of the key,it should be difficult,if not nearly impossible,to decrypt the resulting cipher into readable plaintext.There are many types of encryption techniques that have advanced from history,however the distinction of encryption technique can be broadly categorized in terms of number of key used and way of converting plaintext to the ciphertext.

TYPES OF CIPHERS

HISTORICAL CIPHERS

It is also called Classical Ciphers used processes like substitution and transposition or combination of both called product ciphers.These historic ciphers use the single key for both encryption and decryption(symmetric cipher).To reduce the cipher attacks,in substitution instead of monoalphabetic-a letter for letter,polyalphabetic-one or more letters for single letter substitution can be used.

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MODERN CIPHERS

Modern encryption methods can be divided by two criteria:by type of input data,and by type of key used.

Based upon Input data

STREAM CIPHERS: In this kind of ciphers the plaintext is converted into ciphertext stream by stream.So it encrypts continuous stream of data.Like,character by character conversion.
BLOCK CIPHERS: Here the plaintext is converted into ciphertext block by block.So it encrypts of data of fixed size.

Based upon type of key

Symmetric Key Algorithms(Private Key Cryptography): These techniques use single key for encryption as well as decryption.
Asymmetric Key Algorithms(Public key Cryptography): These techniques use two keys,namely private and public keys.One key is used for encryption and the other is used for decryption.

MY PREVIOUS POST

The Science Behind Cryptography