Difference Between Monoalphabetic Cipher and Polyalphabetic Cipher
Monoalphabetic cipher is one where each character of a plain text is mapped to a fixed other character of cipher text. Examples of monoalphabetic ciphers would include the Caesar-shift cipher, where each letter is shifted based on a numeric key, and the atbash cipher, where each letter is mapped to the letter symmetric to it about the center of the alphabet. The relationship between a character in the plain text and the characters in the cipher text is one-to-one. Example : If a plain text has a character ‘a’ and any key then if it convert into other character say ‘t’ so wherever there is ‘a’ character in plain text it will be mapped to character ‘t’ ,Therefore it is called as monoalphabetic cipher. It is a simple type of substitution cipher. Monoalphabetic ciphers are not that stronger as compared to polyalphabetic cipher. Types of monoalphabetic cipher are
What You Need To Know About Monoalphabetic Cipher
What Is PolyAlphabetic Cipher?A polyalphabetic cipher is any cipher based on substitution, using multiple substitution alphabets. A polyalphabetic cipher uses a number of substitutions at different positions in the message, where a unit from the plaintext is mapped to one of several possibilities in the ciphertext and vice versa. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case. The Enigma machine is more complex but is still fundamentally a polyalphabetic substitution cipher. The Alberti cipher by Leon Battista Alberti around 1467 was an early polyalphabetic cipher. Alberti used a mixed alphabet to encrypt a message, but whenever he wanted to, he would switch to a different alphabet, indicating that he had done so by including an uppercase letter or a number in the cryptogram. For this encipherment Alberti used a decoder device, his cipher disk, which implemented a polyalphabetic substitution with mixed alphabets. For example, when the disc is set as shown, we see that the plaintext letter “e” (on the outside ring) is encrypted to “Z” (on the inside ring). What You Need To Know About Polyalphabetic Cipher
Also Read: Difference Between Substitution Cipher And Transposition Cipher The Difference Between Monoalphabetic Cipher and Polyalphabetic Cipher In Tabular Form
Also Read: Difference Between Block Cipher And Stream Cipher ExamplesPolyalphabetic Cipher Plain Alphabet: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Cipher Alphabet #1: B D F H J L N P R T V Z A C E G I K M O Q S U W Y. Cipher Alphabet #2: Z Y X W V U T S R Q P O N M L K J I H G F E D C B A. Monoalphabetic Cipher Example: An affine cipher E (x)= (ax+b)MOD26 is an example of a monoalphabetic substitution. SummaryA monoalphabetic cipher is one where each symbol in the input (known as the ‘’plaintext’’ is mapped to a fixed symbol in the output (referred to ciphertext). Polyalphabetic cipher is any cipher based on substitution, using multiple substitution alphabets. |