Glossary 2011
From Derek
- Block Cipher – a key cipher operating on fixed-length groups of letters (blocks)
- Cipher – Any general system for hiding the meaning of a message by replacing each letter in the original message with another letter.
- Cipher Cross-off List – a page on the project’s wiki page that contains all details of the project’s cipher investigations. Available at: Cipher Cross-off List
- CipherGUI – The name given to the interactive GUI, developed by the project this year, that implements multiple ciphers.
- Ciphertext – The message (or plaintext) after encryption.
- crawler4j – The OTS Java-based web crawler used by the project this year.
- Digraph cipher – A cipher that encrypts by enciphering the plaintext letters in pairs.
- Frequency Analysis - the study of the frequency of letters or groups of letters in a ciphertext usually performed in order to solve a substitution cipher.
- Index of Coincidence – the probability that any two randomly chosen characters within a text (plaintext or ciphertext) are the same letter.
- Key – the element that turns the general encryption algorithm into a specific method for encryption.
- Mono-alphabetic cipher – a cipher in which the cipher alphabet is fixed throughout the encryption process.
- Pattern Matcher – the module of the Web Crawler search application developed for the project responsible for detecting patterns in web-page content.
- Plaintext – the original message before encryption.
- Poly-alphabetic cipher – a cipher in which the cipher alphabet changes during encryption.
- Polybius square - simple form of fractionating an alphabet into a smaller set of symbols. Most common form is a 5x5 square filled in with alphabet. Letters can be replaced by [row][column] numbers between 1 and 5 each.
- Polygraphic cipher – a cipher which substitutes plaintext letters in groups larger than one.
- Regular Expression or Regex - a concise and flexible means for matching strings of text, such as particular characters, words, or patterns of characters.
- Rubaiyat of Omar Khayyam – the book of Persian Poems linked to the Somerton Man case.
- Seed page – the web page a user enters specifying the starting point from which a web crawler will operate.
- Stenography – the science of hiding the existence of a message, as opposed to cryptography which is the science of hiding the meaning of the message.
- Substitution Cipher – a system of encryption in which each letter of a message is replaced with another character, but retains its position within the message.
- Transposition Cipher – a system of encryption in which each letter of a message changes its position within the message, but retains its identity.
- Web Crawler - a program that browses the internet in a methodical and automated manner.
