| Alphabet |
A set of letters or symbols used to represent a language or system of writing, ordered in a fixed sequence. |
| Autokey Cipher |
"A polyalphabetic cipher similar to the Vigenere Cipher, but using the plaintext itself as part of the key sequence in order to overcome a weakness observed in the original Vigenere Cipher." |
| Brute Force Attack |
A cryptanalytic technique that involves trying every possible key until the correct one is found. This is usually only feasible for small key sizes. |
| Caesar Cipher |
A monoalphabetic substitution cipher in which each letter in the plaintext is shifted a certain number of places down the alphabet. |
| Ciphertext |
The encrypted message or data that is the result of the encryption process and that appears scrambled and unreadable until it is decoded. |
| Cryptanalysis |
The study and practice of breaking codes and ciphers, usually with the goal of deciphering encrypted messages without knowledge of the secret key. |
| Decryption |
The process of converting encoded text to its original form by employing a deciphering algorithm and the identical confidential key utilized during encryption. |
| Encryption |
The procedure of converting plain text into ciphered text by employing an algorithm for secure encoding and a confidential key. |
| Frequency Analysis |
A technique used to analyze and decipher encrypted messages by studying the frequency of occurrence of letters or symbols in the ciphertext. |
| Kasiski Examination |
A cryptanalytic technique used to try and discover the length of the keyword used in a Vigenere Cipher by detecting repeating patterns in the ciphertext. |
| Key |
A piece of information used in conjunction with an encryption algorithm to transform plaintext into ciphertext and vice versa. |
| Modulo Operator |
A mathematical operation that finds the remainder when one integer is divided by another. The Vigenere Cipher uses this operator to perform its encryption and decryption operations. |
| Plaintext |
The original message or data that is to be encrypted or decrypted in its unencrypted form. |
| Playfair Cipher |
A polygraphic substitution cipher that uses a 5x5 table containing a keyword or phrase to encrypt pairs of plaintext letters. |
| Polyalphabetic Cipher |
A cipher that uses multiple substitution alphabets to encrypt the plaintext. The Vigenere Cipher is an example of this type of cipher. |
| Rail Fence Cipher |
A transposition cipher that is created by writing the plaintext horizontally in a zigzag pattern, and then reading off the ciphertext vertically. |
| Substitution Cipher |
A cipher that replaces each plaintext letter or symbol with a different letter or symbol to create the ciphertext. |
| Transposition Cipher |
A cipher that rearranges the order of the plaintext letters or symbols, rather than replacing them with different ones as in a substitution cipher. |
| Vigenere Cipher |
A method of encrypting alphabetic text using a series of different Caesar ciphers based on the letters of a keyword. |
