Digital and Privacy-Preserving Signatures

Digital and Privacy-Preserving Signatures

Digital signatures are a basic cryptographic building block that ensures authenticity (who signed) and integrity (what is signed) of messages. 
In this seminar, we will learn about different types of digital signatures including not only standard RSA and ECDSA signature schemes but also recent schemes secure against quantum adversaries.

We will also take a look at signature schemes that relax the authenticity and integrity properties to increase the privacy of users and/or message like e.g.:
- ring signatures used in the Monero cryptocurrency, 
- pseudonymous signatures used in the German eID, and 
- blind signatures used in e-Cash.

Each week we will discuss papers which will be presented by assigned students. 
All students are required to read the papers carefully and prepare a list of questions for discussion.

The seminar will be held in English.

 

Venue

Zoom, Date: Wednesday 10:15-11:45 (main time), (14:15-15:45, 16:15-17:45 - possible, depending on speaker)

Kick-off meeting (Wed) 27.04.2022, 14:00-15:00

 

Papers

Digital Signatures Foundations

1) Security proofs for signature schemes. [11.05.2022]

2) A method for obtaining digital signatures and public-key cryptosystems (alternatively link1 and link2). [11.05.2022]

3) How to Prove Yourself: Practical Solutions to Identification and Signature Problems. [18.05.2022] Time change: 16:15-17:45

Advanced Signatures

4) Short Signatures Without Random Oracles. [18.05.2022] Time change: 16:15-17:45

5) Short Signatures from the Weil Pairing. [25.05.2022]

6) Compact Multi-Signatures for Smaller Blockchains. [25.05.2022]

PQ Signatures

7) Fiat-Shamir with Aborts: Applications to Lattice and Factoring-Based Signatures. [01.06.2022]

8) CRYSTALS-Dilithium: A Lattice-Based Digital Signature Scheme [01.06.2022]

9) Lattice Signatures Without Trapdoors. [08.06.2022]

Privacy-Preserving Signatures

10) How to Leak a Secret. [08.06.2022]

11) Foundations of Group Signatures: Formal Definitions, Simplified Requirements, and a Construction Based on General Assumptions. [22.06.2022]

12) Short Group Signatures [22.06.2022]

13) Direct Anonymous Attestation. [29.06.2022]

14) Domain-Specific Pseudonymous Signatures for the German Identity Card. [29.06.2022]

15) Sanitizable signatures. [06.07.2022]

16) Structure-Preserving Signatures on Equivalence Classes and Constant-Size Anonymous Credentials. [06.07.2022]

 

Instructors

Lucjan Hanzlik (lucjan.hanzlik@cispa.de)