Lecturer: Carlo Bertoluzza  

Course name: Crittografia e protezione dell'informazione
Course code: 064028
Degree course: Ingegneria Informatica
Disciplinary field of science: ING-INF/05
L'insegnamento è caratterizzante per: Ingegneria Informatica
University credits: CFU 5
Course website: n.d.

Specific course objectives

Aim of the course: give a sufficiently in-depht knowledge of the most used private and public key cipher sistems.

Course programme

After a short exposition of the history of the cryptography, the two principal classes of the cipher sistems (public and private keys) are presented. Moreover some applications are described which are used against the active cryptanalisis. In paricular data integrity, key management and digital signature.

Classical cryptosistems

• 1. A brief history of cryptography.
• 2. Monoalphabetic and polialphabetic substitutions.
• 3. Classical and column tranposition, Hill cipher.
• 4. Mechanical Cryptographic Devices (ENIGMA and M-209)
• 5. General definition of Cipher Sistems, closed and pure ciphers.
• 6. Cryptogram and message residue classes.
• 7. Shannon theory and perfect secrecy.
• 8. A perfect system: the One Time Pad

Private Key Cryptosistems

• 1. Flow Chiphers.
• - Shift register as key generators.
• - Characteristic polinomials and periodicity.
• - Golomb criteria and randomness.
• - Non-linear and composed shift registers, Multip;exars.
• 2. Block ciphers: gneral structure.
• - Data Encryption Standard.
• - Finite fields and AES cipher.
• - Modular arithmetic and IDEA cipher.

Public Key Cryptosystems

• 1. A survey on complexity and modular arithmetic.
• 2. Public key ciphers.
• - Subset sum problem and Merkle-Hellmann cipher.
• - Integer facoring and RSA.
• - Discrete square root and Rabin cipher.
• - Discrete logarithm and ElGamal cipher.
• 3. The Omura-Massey "without key" cipher.

Applications against active cryptanalisis

• 1. Hash function and data integrity.
• 2. Key generation, Key distribution and Key management.
• 3. Digital signature with appendix.
• - General structure and compression funtion.
• - Logarithm based ElGamal and DSA signature.
• - Square rooth based Fiat-Shamir signature
• 4. Digital signature with recovery.
• - General structure and redundancy funtion.
• - RSA based protocol
• - Square root based Rabin protocol
• 5. Arbitrated signature: the one-time Rabin scheme.
• 6. Blind signature: the Caum protocol.

Course entry requirements

Elementary notions of probability theory in finite spaces. In particular Bayes theorem, random variables and laws of large nombers.

Course structure and teaching

Lectures (hours/year in lecture theatre): 40
Practical class (hours/year in lecture theatre): 0
Practicals / Workshops (hours/year in lecture theatre): 0
Project work (hours/year in lecture theatre): 0

Suggested reading materials

Becker & Piper. Cypher Syatems. Northwood Books, 1982.

D.R. Stinson. Cryptography. Chapman & Hall 2002.

Menezes, van Oorshot, Vanstone. Handbook of Applied Cryptography. CRC Press, 1996.

Testing and exams