Concept

Sybil attack

Related publications (15)

Breaking Blockchain Rationality with Out-of-Band Collusion

Bryan Alexander Ford, Verónica del Carmen Estrada Galiñanes, Louis-Henri Manuel Jakob Merino, Haoqian Zhang, Mahsa Bastankhah

Blockchain systems often rely on rationality assumptions for their security, expecting that nodes are motivated to maximize their profits. These systems thus design their protocols to incentivize nodes to execute the honest protocol but fail to consider ou ...

Cham2024

CALYPSO: Private Data Management for Decentralized Ledgers

Bryan Alexander Ford, Linus Gasser, Eleftherios Kokoris Kogias, 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

CALYPSO: Private Data Management for Decentralized Ledgers

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

ASSOC COMPUTING MACHINERY2020

Identity and Personhood in Digital Democracy: Evaluating Inclusion, Equality, Security, and Privacy in Pseudonym Parties and Other Proofs of Personhood

Bryan Alexander Ford

Digital identity seems at first like a prerequisite for digital democracy: how can we ensure “one person, one vote” online without identifying voters? But the full gamut of digital identity solutions – e.g., online ID checking, biometrics, self-sovereign i ...

2020

Proof-of-Personhood: Redemocratizing Permissionless Cryptocurrencies

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

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

Trustworthy Cloud Storage

Maxime Augier

The Cloud trend is an attempt to leverage economics of scale in the domain of computing resources. Unfortunately, this often means losing control of the lower levels of a computer system, and exposing users to new threat vectors. These threats may be signi ...

EPFL2016

Bitcoin Meets Collective Signing

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

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 ...

2016

Enhancing Bitcoin Security and Performance with Strong Consistency via Collective Signing

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

Usenix Assoc2016

Security Analysis of Accountable Anonymity in Dissent

Bryan Alexander Ford, Henry Nathaniel Corrigan-Gibbs

Users often wish to communicate anonymously on the Internet, for example in group discussion or instant messaging forums. Existing solutions are vulnerable to misbehaving users, however, who may abuse their anonymity to disrupt communication. Dining Crypto ...

2014

Hang With Your Buddies to Resist Intersection Attacks

Bryan Alexander Ford

Some anonymity schemes, such as DC-nets and MIX cascades, can guarantee anonymity even against traffic analysis – provided messages are independent and unlinkable. Users in practice often desire pseudonymity – sending messages intentionally linkable to eac ...

2013

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