University of Virginia, Department of Computer Science CS588: Cryptography, Spring 2005

### Quiz

22 March 2005

Name: ___________________________________________

Work alone. No notes. No books. No other materials. Answer all questions (both sides).

RSA Paper
1. Here is the RSA algorithm, with some pieces missing. Fill in the blanks:

1. Pick 2 large secret primes, p and q.

2. Let n = _______________ [blank 1]

3. Choose e and d so: ed ≡ 1 mod _____________ [blank 2]
4. Encryption function (public): E(M) = Me mod n.

5. Decryption function (private): D(C) = ___________________ [blank 3]

2. What is the private key?

3. What is the range of M that can be reliably transmitted using RSA?

4. What is φ(185)? (Hint: divide by 5)

Continues on back side

Practical Techniques for Searches on Encrypted Data

5. Check all of the below statements that are true about the paper:
1. ___ It describes techniques for searching encrypted data that can search a document of length n in O(n2) stream cipher and block cipher operations.
2. ___ It describes techniques for searching encrypted data that can search a document of length n in O(n) stream cipher and block cipher operations.
3. ___ It mentions the birthday paradox.
4. ___ It presents techniques that are provably secure.
5. ___ For the final scheme, when Alice sends a search query to Bob, Bob can learn something about which documents contain Alice's query term.

Security of RSA