FREE Encryption Sample: Caesar & Vernam | AQA A Level Computer Science 7517 | 2 Worksheets + Answers

Two free sample worksheets on encryption for AQA A Level Computer Science
(7517), with full answer keys, so you can see exactly what the full pack
contains before buying anything.

Each sheet fills in a shifted alphabet, encrypts one word with a Caesar cipher
and decrypts another, then encrypts five characters with a Vernam cipher -
ASCII in eight bits, exclusive OR with the one-time pad - and decrypts an
intercepted message the same way. Then a Caesar cipher of unknown shift to
break, given the first word of the plaintext, and a written question.

The convention this topic argues about is printed on the page: the Vernam
cipher here works on BITS, combined with exclusive OR, and not by adding
letter positions modulo 26 as a good number of books do. Those are two
different answers to the same question.

These two sheets are not in the paid pack - they are extra, so nothing is
wasted if you buy it afterwards.

The full pack contains 20 worksheets and 20 answer keys, on twenty different
shifts, words and one-time pads. Search Tes for “AQA A Level Computer Science
Caesar and Vernam” to find it.

If these are useful, a review is genuinely appreciated - it is the only way
other teachers find resources like this.