Final41-50

# Final41-50 - 41. What is the Caesar Shift? How many...

This preview shows pages 1–2. Sign up to view the full content.

41. What is the Caesar Shift? How many different possibilities are there when encoding clear text with the Caesar Shift? What does this mean for the security of this encryption type? a. In cryptography, a Caesar cipher, also known as a Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. Alphabet shift +3. For example, with a shift of 3, A would be replaced by D, B would become E, and so on. The method is named after Julius Caesar, who used it to communicate with his generals. As with all single alphabet substitution ciphers, the Caesar cipher is easily broken and in practice offers essentially no communication security. 42. Decipher Julius Caesar’s message to Brutus (supposedly, he liked to use ROT 3): “Glg brx gr brxu krphzrun, rk Euxwxv?” a. Did you do your homework, oh Brutus? 43. What is Simple Substitution? Explain how known frequency distributions of letters in a language are used to break this cipher. a. Relies on permutation; each letter is substituted for another letter and needed a code book to know substitutions, now a 26-letter factorial alphabet b. In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system; the "units" may be

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 09/29/2009 for the course GEOL 108Lg taught by Professor Anderson during the Spring '07 term at USC.

### Page1 / 2

Final41-50 - 41. What is the Caesar Shift? How many...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online