Sebastian Ramacher

I am a researcher in cryptography and PhD student at IAIK, Graz University of Technology. My main research interests are in the field of public key cryptography with a focus on post-quantum signature schemes and modern public key cryptography.

Publications and Talks

Conferences and Journals

2019 Daniel Kales, Olamide Omolola, Sebastian Ramacher. Revisting User Privacy for Certificate Transparency EuroS&P 2019 (accepted)
2019 Itai Dinur, Daniel Kales, Angela Promitzer, Sebastian Ramacher, Christian Rechberger. Linear Equivalence of Block Ciphers with Partial Non-Linear Layers: Application to LowMC Eurocrypt 2019 (to appear)
2018 David Derler, Sebastian Ramacher, Daniel Slamanig. Generic Double-Authentication Preventing Signatures and a Post-Quantum Instantiation ProvSec 2018
2018 David Derler, Sebastian Ramacher, Daniel Slamanig. Post-Quantum Zero-Knowledge Proofs for Accumulators with Applications to Ring Signatures from Symmetric-Key Primitives. PQCrypto 2018
2018 David Derler, Stephan Krenn, Thomas Lorünser, Sebastian Ramacher, Daniel Slamanig, Christoph Striecks: Revisiting Proxy Re-Encryption: Forward Secrecy, Improved Security and Applications. PKC 2018
2018 David Derler, Sebastian Ramacher, Daniel Slamanig. Short Double- and N-Times-Authentication-Preventing Signatures from ECDSA and More. EuroS&P 2018
2017 Melissa Chase, David Derler, Steven Goldfeder Claudio Orlandi, Sebastian Ramacher, Christian Rechberger, Daniel Slamanig, Greg Zaverucha. Post-Quantum Zero-Knowledge and Signatures from Symmetric-Key Primitives. CCS 2017
2017 David Derler, Sebastian Ramacher, Daniel Slamanig. Homomorphic Proxy Re-Authenticators and Applications to Verifiable Multi-User Data Aggregation. FC 2017.
2015 Alfred Geroldinger, Sebastian Ramacher, Andreas Reinhart. On v-Marot Mori rings and C-rings. Journal of the Korean Mathematical Society Vol. 52 No. 1/2015

Preprints

2017 Daniel Kales, Léo Perrin, Angela Promitzer, Sebastian Ramacher, Christian Rechberger. Improvements to the Linear Layer of LowMC: A Faster Picnic
2016 David Derler, Claudio Orlandi, Sebastian Ramacher, Christian Rechberger, Daniel Slamanig. Digital Signatures from Symmetric-Key Primitives

Talks

2018 Generic Double-Authentication Preventing Signatures and a Post-Quantum Instantiation at ProvSec 2018.
2018 Post-Quantum Zero-Knowledge Proofs for Accumulators with Applications to Ring Signatures from Symmetric-Key Primitives at PQCrypto 2018.
2018 Short Double- and N-Times-Authentication-Preventing Signatures from ECDSA and More at EuroS&P 2018.
2017 Post-Quantum Zero-Knowledge and Signatures from Symmetric-Key Primitives at CCS 2017 on November 2, 2017 (together with Steven Goldfeder).
2017 Post-Quantum Zero-Knowledge and Signatures from Symmetric-Key Primitives at Microsoft Research on October 26, 2017.
2017 Post-Quantum Zero-Knowledge and Signatures from Symmetric-Key Primitives at CryptoSymposium 2017 on March 28, 2017.

NIST PQC Competition: Picnic

The Picnic family of digital signature algorithms is designed to provide security against attacks by quantum computers, in addition to attacks by classical computers. The building blocks are a zero-knowledge proof system (with post-quantum security), and symmetric key primitives like hash functions and block ciphers, with well-understood post-quantum security. An implementation optimized for speed is available on GitHub. Packages for Ubuntu bionic and cosmic are available as PPA.

Picnic is a round 2 candidate in the ongoing NIST PQC effort.

Projects

Other Activities

Reviewer for International Conferences

Eurocrypt 2019, ACNS 2018, APKC 2018, CT-RSA 2018, ICDCS 2018, Asiacrypt 2017, SECPID 2017, Eurocrypt 2017, Africacrypt 2016, ICISC 2016

Teaching

I am currently involved with the following courses:

Potential topics for student projects, bachelor’s and master’s thesis can be found here:

Contact information