What Is a Cipher
Cipher when used in the technical terms means the encryption or the decryption of the standard series which formulate the procedure or the process. But when the term cipher is used in the non technical terms the same word is represented with the meaning code, even though the concepts and ideas behind these terms are different in cryptography. In the classical and conventional cryptography the term ciphers was different from the term codes. Codes were used and operated by substituting or replacing the words in the place of the codes which should be done as per the large book of codes that is linked and associated with the random characters and the numbers to form a complete word or a phrase.
The time when the original cipher is used this information and the details are known as the plaintext, and further the encrypted cipher is known as the cipher text. The cipher text format includes all the different kind of information similar to the plaintext format, but the only thing different is that the format will not be readable by the human beings or the computer machine without any proper mechanism which is able to decrypt the actual message and it should also resemble at the random approach for those people who not intend to read the message. The function of a cipher generally depends upon the piece of any auxiliary information or the data which is known as the key. The process of encrypting is different which depends upon the key, which generally changes the descriptive function of the algorithm. The key should be selected before the use of cipher which is helpful to encrypt the message. Without the accurate knowledge about the key, it will be a difficult task to decrypt the cipher text the readable plaintext.
Cipher and their categorization
The ciphers can be categorized on the basis of if they are working on the blocks and symbols of generally fixed or set size or if they are working on the regular stream of the symbols. The categorization also depends upon if the key is used basically for both the encrypting and decryption of the algorithms or whether the key is basically used for every single algorithm. Basically there are two kinds of ciphers which can be historical cipher and it can be also modern cipher. The Historical ciphers are the most classical and the conventional ciphers which uses the pen and paper kinds to transfer the phrase or the word with the help of code. Like BEST DAD can be written as APLK EME where the alphabet B represents A, alphabet E represent P, alphabet S represent L and so on. These are the most simple and easy for of ciphers which were used long time back and so they are known as the Historical Ciphers whereas the modern ciphers are the latest methods of encrypting the text by the use of key.