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 ...
Cham2024CALYPSO: 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 ...
2021CALYPSO: 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 ...
ASSOC COMPUTING MACHINERY2020Identity and Personhood in Digital Democracy: Evaluating Inclusion, Equality, Security, and Privacy in Pseudonym Parties and Other Proofs of Personhood
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 ...
2020Proof-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 ...
IEEE2017Trustworthy Cloud Storage
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 ...
EPFL2016Bitcoin 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 ...
2016Enhancing Bitcoin Security and Performance with Strong Consistency via Collective Signing
Bryan Alexander Ford, Linus Gasser, 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 ...
Usenix Assoc2016Security 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 ...
2014Hang With Your Buddies to Resist Intersection Attacks
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