Publications by Philipp Svetolik Jovanovic

CALYPSO: Private Data Management for Decentralized Ledgers

Linus Gasser, Eleftherios Kokoris Kogias, Bryan Alexander Ford, Philipp Svetolik Jovanovic, Enis Ceyhun Alp

Distributed ledgers provide high availability and integrity, making them a key enabler for practical and secure computation of distributed workloads among mutually distrustful parties. Many practical applications also require strong confidentiality, howeve ...

2021

Beyond Conventional Security in Sponge-Based Authenticated Encryption Modes

Philipp Svetolik Jovanovic

The Sponge function is known to achieve 2c/2 security, where c is its capacity. This bound was carried over to its keyed variants, such as SpongeWrap, to achieve a min{2c/2,2 kappa} security bound, with kappa the key length. Similarly, many CAESAR competit ...

SPRINGER2019

Cryptographically verifiable data structure having multi-hop forward and backwards links and associated systems and methods

Linus Gasser, Eleftherios Kokoris Kogias, Bryan Alexander Ford, Philipp Svetolik Jovanovic

Data storage and retrieval systems, methods, and computer-readable media utilize a cryptographically verifiable data structure that facilitates verification of a transaction in a decentralized peer-to-peer environment using multi-hop backwards and forwards ...

2018

On Enforcing the Digital Immunity of a Large Humanitarian Organization

Jean-Pierre Hubaux, Bryan Alexander Ford, Philipp Svetolik Jovanovic, Juan Ramón Troncoso-Pastoriza

Humanitarian action, the process of aiding individuals in situations of crises, poses unique information-security challenges due to natural or manmade disasters, the adverse environments in which it takes place, and the scale and multidisciplinary nature o ...

2018

OmniLedger: A Secure, Scale-Out, Decentralized Ledger via Sharding

Linus Gasser, Nicolas Gailly, Eleftherios Kokoris Kogias, Bryan Alexander Ford, Philipp Svetolik Jovanovic

Designing a secure permissionless distributed ledger (blockchain) that performs on par with centralized payment processors, such as Visa, is a challenging task. Most existing distributed ledgers are unable to scale-out, i.e., to grow their total processing ...

IEEE2018

CHAINIAC: Proactive Software-Update Transparency via Collectively Signed Skipchains and Verified Builds

Linus Gasser, Nicolas Gailly, Kirill Nikitin, Eleftherios Kokoris Kogias, Bryan Alexander Ford, Ismail Khoffi, Philipp Svetolik Jovanovic

Software-update mechanisms are critical to the security of modern systems, but their typically centralized design presents a lucrative and frequently attacked target. In this work, we propose CHAINIAC, a decentralized software-update framework that elimina ...

USENIX Association2017

Proof-of-Personhood: Redemocratizing Permissionless Cryptocurrencies

Linus Gasser, Nicolas Gailly, Eleftherios Kokoris Kogias, Bryan Alexander Ford, Maria Fernanda Borge Chavez, Philipp Svetolik Jovanovic

Permissionless blockchain-based cryptocurrencies commonly use proof-of-work (PoW) or proof-of-stake (PoS) to ensure their security, e.g. to prevent double spending attacks. However, both approaches have disadvantages: PoW leads to massive amounts of wasted ...

IEEE2017

Scalable Bias-Resistant Distributed Randomness

Linus Gasser, Nicolas Gailly, Eleftherios Kokoris Kogias, Bryan Alexander Ford, Ismail Khoffi, Philipp Svetolik Jovanovic

Bias-resistant public randomness is a critical component in many (distributed) protocols. Existing solutions do not scale to hundreds or thousands of participants, as is needed in many decentralized systems. We propose two large-scale distributed protocols ...

IEEE2017

Enhancing Bitcoin Security and Performance with Strong Consistency via Collective Signing

Linus Gasser, Nicolas Gailly, Bryan Alexander Ford, Ismail Khoffi, Philipp Svetolik Jovanovic

While showing great promise, Bitcoin requires users to wait tens of minutes for transactions to commit, and even then, offering only probabilistic guarantees. This paper introduces ByzCoin, a novel Byzantine consensus protocol that leverages scalable colle ...

USENIX Association2016

Keeping Authorities “Honest or Bust” with Decentralized Witness Cosigning

Linus Gasser, Nicolas Gailly, Bryan Alexander Ford, Ismail Khoffi, Philipp Svetolik Jovanovic

The secret keys of critical network authorities – such as time, name, certificate, and software update services – represent high-value targets for hackers, criminals, and spy agencies wishing to use these keys secretly to compromise other hosts. To protect ...

IEEE2016

Improved Masking for Tweakable Blockciphers with Applications to Authenticated Encryption

Robert Granger, Philipp Svetolik Jovanovic

A popular approach to tweakable blockcipher design is via masking, where a certain primitive (a blockcipher or a permutation) is preceded and followed by an easy-to-compute tweak-dependent mask. In this work, we revisit the principle of masking. We do so a ...

Springer Int Publishing Ag2016