Study Questions 1

Question 1

What are the adversary’s goal and capabilities in IND-CPA and IND-CCA?

Answer 1

IND-CPA: Adversary cannot reliably distinguish ciphertexts of different chosen plaintexts.

IND-CCA: Adversary, even with access to encryption and decryption oracles, cannot reliably distinguish the encryption of the target ciphertext from a random string.

Question 2

What is the difference between an IV (Initial Value) and a Nonce?

Answer 2

An IV in its broadest sense, is just the initial value used to start some iterated process. This IV ensures that each message encrypts differently, such that seeing multiple messages encrypted with the same key doesn’t give the attacker any more information than just seeing a single long message.

A Nonce in its broadest sense, is just a number used only once. Lägg till mer här…