When is an encryption scheme secure?: Answers

Let us consider the answers to the previous article’s questions on encryption schemes and security.

1. If the adversary simply guessed which message it received it would have ½ chance of winning the game anyway!
2. If we gave the adversary more power in the game it would increase the strength of the definition. For example, we could allow the adversary to ask to see some examples of messages and their decryptions (not the one it was given though!).

This article was written by David Butler, one of the course creators and teachers at Oxbridge Inspire. David is studying for a PhD at the Alan Turing Institute in London.

If you enjoyed this article, you might consider coming to our course in Cambridge this summer on the Mathematics behind Cryptography.