--- _id: '8311' abstract: - lang: eng text: 'One of the core promises of blockchain technology is that of enabling trustworthy data dissemination in a trustless environment. What current blockchain systems deliver, however, is slow dissemination of public data, rendering blockchain technology unusable in settings where latency, transaction capacity, or data confidentiality are important. In this thesis we focus on providing solutions on two of the most pressing problems blockchain technology currently faces: scalability and data confidentiality. To address the scalability issue, we present OMNILEDGER, a novel scale-out distributed ledger that preserves long-term security under permissionless operation. It ensures security and correctness by using a bias-resistant public-randomness protocol for choosing large, statistically representative shards that process transactions, and by introducing an efficient cross-shard commit protocol that atomically handles transactions affecting multiple shards. To enable secure sharing of confidential data we present CALYPSO, the first fully decentralized, auditable access-control framework for secure blockchain-based data sharing which builds upon two abstractions. First, on-chain secrets enable collective management of (verifiably shared) secrets under a Byzantine adversary where an access-control blockchain enforces user-specific access rules and a secret-management cothority administers encrypted data. Second, skipchain-based identity and access management enables efficient administration of dynamic, sovereign identities and access policies and, in particular, permits clients to maintain long-term relationships with respect to evolving user identities thanks to the trust-delegating forward links of skipchains. In order to build OMNILEDGER and CALYPSO, we first build a set of tools for efficient decentralization, which are presented in Part II of this dissertation. These tools can be used in decentralized and distributed systems to achieve (1) scalable consensus (BYZCOIN), (2) bias- resistant distributed randomness creations (RANDHOUND), and (3) relationship-keeping between independently updating communication endpoints (SKIPCHAINIAC). Although we use this tools in the scope off this thesis, they can be (and already have been) used in a far wider scope.' article_processing_charge: No author: - first_name: Eleftherios full_name: Kokoris Kogias, Eleftherios id: f5983044-d7ef-11ea-ac6d-fd1430a26d30 last_name: Kokoris Kogias citation: ama: Kokoris Kogias E. Secure, confidential blockchains providing high throughput and low latency. 2019. doi:10.5075/epfl-thesis-7101 apa: Kokoris Kogias, E. (2019). Secure, confidential blockchains providing high throughput and low latency. École Polytechnique Fédérale de Lausanne. https://doi.org/10.5075/epfl-thesis-7101 chicago: Kokoris Kogias, Eleftherios. “Secure, Confidential Blockchains Providing High Throughput and Low Latency.” École Polytechnique Fédérale de Lausanne, 2019. https://doi.org/10.5075/epfl-thesis-7101. ieee: E. Kokoris Kogias, “Secure, confidential blockchains providing high throughput and low latency,” École Polytechnique Fédérale de Lausanne, 2019. ista: Kokoris Kogias E. 2019. Secure, confidential blockchains providing high throughput and low latency. École Polytechnique Fédérale de Lausanne. mla: Kokoris Kogias, Eleftherios. Secure, Confidential Blockchains Providing High Throughput and Low Latency. École Polytechnique Fédérale de Lausanne, 2019, doi:10.5075/epfl-thesis-7101. short: E. Kokoris Kogias, Secure, Confidential Blockchains Providing High Throughput and Low Latency, École Polytechnique Fédérale de Lausanne, 2019. date_created: 2020-08-27T11:22:24Z date_published: 2019-09-27T00:00:00Z date_updated: 2021-12-20T15:30:47Z day: '27' degree_awarded: PhD doi: 10.5075/epfl-thesis-7101 extern: '1' language: - iso: eng main_file_link: - open_access: '1' url: https://www.doi.org/10.5075/epfl-thesis-7101 month: '09' oa: 1 oa_version: Published Version page: '244' publication_status: published publisher: École Polytechnique Fédérale de Lausanne status: public supervisor: - first_name: Bryan Alexander full_name: Ford, Bryan Alexander last_name: Ford title: Secure, confidential blockchains providing high throughput and low latency type: dissertation user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2019' ... --- _id: '8314' abstract: - lang: eng text: "Off-chain protocols (channels) are a promising solution to the scalability and privacy challenges of blockchain payments. Current proposals, however, require synchrony assumptions to preserve the safety of a channel, leaking to an adversary the exact amount of time needed to control the network for a successful attack. In this paper, we introduce Brick, the first payment channel that remains secure under network asynchrony and concurrently provides correct incentives. The core idea is to incorporate the conflict resolution process within the channel by introducing a rational committee of external parties, called Wardens. Hence, if a party wants to close a channel unilaterally, it can only get the committee's approval for the last valid state. Brick provides sub-second latency because it does not employ heavy-weight consensus. Instead,\r\nBrick uses consistent broadcast to announce updates and close the channel, a light-weight abstraction that is powerful enough to preserve safety and liveness to any rational parties. Furthermore, we consider permissioned blockchains, where the additional property of auditability might be desired for regulatory purposes. We introduce Brick+, an off-chain construction that provides auditability on top of Brick without conflicting with its privacy guarantees. We formally define the properties our payment channel construction should fulfill, and prove that both Brick and Brick+ satisfy them. We also design incentives for Brick such that honest and rational behavior aligns. Finally, we provide a reference implementation of the smart contracts in Solidity." article_number: '1905.11360' article_processing_charge: No author: - first_name: Georgia full_name: Avarikioti, Georgia last_name: Avarikioti - first_name: Eleftherios full_name: Kokoris Kogias, Eleftherios id: f5983044-d7ef-11ea-ac6d-fd1430a26d30 last_name: Kokoris Kogias - first_name: Roger full_name: Wattenhofer, Roger last_name: Wattenhofer - first_name: Dionysis full_name: Zindros, Dionysis last_name: Zindros citation: ama: 'Avarikioti G, Kokoris Kogias E, Wattenhofer R, Zindros D. Brick: Asynchronous payment channels. arXiv.' apa: 'Avarikioti, G., Kokoris Kogias, E., Wattenhofer, R., & Zindros, D. (n.d.). Brick: Asynchronous payment channels. arXiv.' chicago: 'Avarikioti, Georgia, Eleftherios Kokoris Kogias, Roger Wattenhofer, and Dionysis Zindros. “Brick: Asynchronous Payment Channels.” ArXiv, n.d.' ieee: 'G. Avarikioti, E. Kokoris Kogias, R. Wattenhofer, and D. Zindros, “Brick: Asynchronous payment channels,” arXiv. .' ista: 'Avarikioti G, Kokoris Kogias E, Wattenhofer R, Zindros D. Brick: Asynchronous payment channels. arXiv, 1905.11360.' mla: 'Avarikioti, Georgia, et al. “Brick: Asynchronous Payment Channels.” ArXiv, 1905.11360.' short: G. Avarikioti, E. Kokoris Kogias, R. Wattenhofer, D. Zindros, ArXiv (n.d.). date_created: 2020-08-27T11:36:54Z date_published: 2019-05-27T00:00:00Z date_updated: 2021-01-12T08:18:04Z day: '27' extern: '1' external_id: arxiv: - '1905.11360' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1905.11360 month: '05' oa: 1 oa_version: Preprint publication: arXiv publication_status: submitted status: public title: 'Brick: Asynchronous payment channels' type: preprint user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2019' ... --- _id: '8315' abstract: - lang: eng text: "Sharding distributed ledgers is the most promising on-chain solution for scaling blockchain technology. In this work, we define and analyze the properties a sharded distributed ledger should fulfill. More specifically, we show that a sharded blockchain cannot be scalable under a fully adaptive adversary, but it can scale up to $O(n/\\log n)$ under an epoch-adaptive adversary. This is possible only if the distributed ledger creates succinct proofs of the valid state updates at the end of each epoch. Our model builds upon and extends the Bitcoin backbone protocol by defining consistency and\r\nscalability. Consistency encompasses the need for atomic execution of cross-shard transactions to preserve safety, whereas scalability encapsulates the speedup a sharded system can gain in comparison to a non-sharded system. In\r\norder to show the power of our framework, we analyze the most prominent sharded blockchains and either prove their correctness (OmniLedger, RapidChain) under our model or pinpoint where they fail to balance the consistency and\r\nscalability requirements (Elastico, Monoxide). " article_number: '1910.10434' article_processing_charge: No author: - first_name: Georgia full_name: Avarikioti, Georgia last_name: Avarikioti - first_name: Eleftherios full_name: Kokoris Kogias, Eleftherios id: f5983044-d7ef-11ea-ac6d-fd1430a26d30 last_name: Kokoris Kogias - first_name: Roger full_name: Wattenhofer, Roger last_name: Wattenhofer citation: ama: 'Avarikioti G, Kokoris Kogias E, Wattenhofer R. Divide and scale: Formalization of distributed ledger sharding protocols. arXiv.' apa: 'Avarikioti, G., Kokoris Kogias, E., & Wattenhofer, R. (n.d.). Divide and scale: Formalization of distributed ledger sharding protocols. arXiv.' chicago: 'Avarikioti, Georgia, Eleftherios Kokoris Kogias, and Roger Wattenhofer. “Divide and Scale: Formalization of Distributed Ledger Sharding Protocols.” ArXiv, n.d.' ieee: 'G. Avarikioti, E. Kokoris Kogias, and R. Wattenhofer, “Divide and scale: Formalization of distributed ledger sharding protocols,” arXiv. .' ista: 'Avarikioti G, Kokoris Kogias E, Wattenhofer R. Divide and scale: Formalization of distributed ledger sharding protocols. arXiv, 1910.10434.' mla: 'Avarikioti, Georgia, et al. “Divide and Scale: Formalization of Distributed Ledger Sharding Protocols.” ArXiv, 1910.10434.' short: G. Avarikioti, E. Kokoris Kogias, R. Wattenhofer, ArXiv (n.d.). date_created: 2020-08-27T11:37:43Z date_published: 2019-10-23T00:00:00Z date_updated: 2021-01-12T08:18:05Z day: '23' extern: '1' external_id: arxiv: - '1910.10434' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1910.10434 month: '10' oa: 1 oa_version: Preprint publication: arXiv publication_status: submitted status: public title: 'Divide and scale: Formalization of distributed ledger sharding protocols' type: preprint user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2019' ... --- _id: '8313' abstract: - lang: eng text: The present invention concerns a computer-implemented method for secure data exchange between a sender (A) and a recipient (B), wherein the method is performed by the sender (A) and comprises encrypting data using a symmetric key k, creating a write transaction T W , wherein the write transaction T W comprises information usable to derive the symmetric key k and an access policy identifying the recipient (B) as being allowed to decrypt the encrypted data, providing the recipient (B) access to the encrypted data, and sending the write transaction T W to a first group of servers (AC) for being stored in a blockchain data structure maintained by the first group of servers (AC). applicant: - 'École Polytechnique Fédérale De Lausanne ' article_processing_charge: No author: - first_name: Bryan full_name: Ford, Bryan last_name: Ford - first_name: Linus full_name: Gasser, Linus last_name: Gasser - first_name: Eleftherios full_name: Kokoris Kogias, Eleftherios id: f5983044-d7ef-11ea-ac6d-fd1430a26d30 last_name: Kokoris Kogias - first_name: Philipp full_name: Janovic, Philipp last_name: Janovic citation: ama: Ford B, Gasser L, Kokoris Kogias E, Janovic P. Methods and systems for secure data exchange. 2019. apa: Ford, B., Gasser, L., Kokoris Kogias, E., & Janovic, P. (2019). Methods and systems for secure data exchange. chicago: Ford, Bryan, Linus Gasser, Eleftherios Kokoris Kogias, and Philipp Janovic. “Methods and Systems for Secure Data Exchange,” 2019. ieee: B. Ford, L. Gasser, E. Kokoris Kogias, and P. Janovic, “Methods and systems for secure data exchange.” 2019. ista: Ford B, Gasser L, Kokoris Kogias E, Janovic P. 2019. Methods and systems for secure data exchange. mla: Ford, Bryan, et al. Methods and Systems for Secure Data Exchange. 2019. short: B. Ford, L. Gasser, E. Kokoris Kogias, P. Janovic, (2019). date_created: 2020-08-27T11:24:44Z date_published: 2019-08-22T00:00:00Z date_updated: 2022-01-05T14:00:32Z day: '22' extern: '1' ipc: G06F21/62 ; H04L9/08 ; H04L9/32 ipn: WO2019158209 (A1) main_file_link: - open_access: '1' url: https://patents.google.com/patent/WO2019158209A1 month: '08' oa: 1 oa_version: Published Version publication_date: 2019-08-22 status: public title: Methods and systems for secure data exchange type: patent user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2019' ... --- _id: '8405' abstract: - lang: eng text: Atomic-resolution structure determination is crucial for understanding protein function. Cryo-EM and NMR spectroscopy both provide structural information, but currently cryo-EM does not routinely give access to atomic-level structural data, and, generally, NMR structure determination is restricted to small (<30 kDa) proteins. We introduce an integrated structure determination approach that simultaneously uses NMR and EM data to overcome the limits of each of these methods. The approach enables structure determination of the 468 kDa large dodecameric aminopeptidase TET2 to a precision and accuracy below 1 Å by combining secondary-structure information obtained from near-complete magic-angle-spinning NMR assignments of the 39 kDa-large subunits, distance restraints from backbone amides and ILV methyl groups, and a 4.1 Å resolution EM map. The resulting structure exceeds current standards of NMR and EM structure determination in terms of molecular weight and precision. Importantly, the approach is successful even in cases where only medium-resolution cryo-EM data are available. article_number: '2697' article_processing_charge: No article_type: original author: - first_name: Diego F. full_name: Gauto, Diego F. last_name: Gauto - first_name: Leandro F. full_name: Estrozi, Leandro F. last_name: Estrozi - first_name: Charles D. full_name: Schwieters, Charles D. last_name: Schwieters - first_name: Gregory full_name: Effantin, Gregory last_name: Effantin - first_name: Pavel full_name: Macek, Pavel last_name: Macek - first_name: Remy full_name: Sounier, Remy last_name: Sounier - first_name: Astrid C. full_name: Sivertsen, Astrid C. last_name: Sivertsen - first_name: Elena full_name: Schmidt, Elena last_name: Schmidt - first_name: Rime full_name: Kerfah, Rime last_name: Kerfah - first_name: Guillaume full_name: Mas, Guillaume last_name: Mas - first_name: Jacques-Philippe full_name: Colletier, Jacques-Philippe last_name: Colletier - first_name: Peter full_name: Güntert, Peter last_name: Güntert - first_name: Adrien full_name: Favier, Adrien last_name: Favier - first_name: Guy full_name: Schoehn, Guy last_name: Schoehn - first_name: Paul full_name: Schanda, Paul id: 7B541462-FAF6-11E9-A490-E8DFE5697425 last_name: Schanda orcid: 0000-0002-9350-7606 - first_name: Jerome full_name: Boisbouvier, Jerome last_name: Boisbouvier citation: ama: Gauto DF, Estrozi LF, Schwieters CD, et al. Integrated NMR and cryo-EM atomic-resolution structure determination of a half-megadalton enzyme complex. Nature Communications. 2019;10. doi:10.1038/s41467-019-10490-9 apa: Gauto, D. F., Estrozi, L. F., Schwieters, C. D., Effantin, G., Macek, P., Sounier, R., … Boisbouvier, J. (2019). Integrated NMR and cryo-EM atomic-resolution structure determination of a half-megadalton enzyme complex. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-019-10490-9 chicago: Gauto, Diego F., Leandro F. Estrozi, Charles D. Schwieters, Gregory Effantin, Pavel Macek, Remy Sounier, Astrid C. Sivertsen, et al. “Integrated NMR and Cryo-EM Atomic-Resolution Structure Determination of a Half-Megadalton Enzyme Complex.” Nature Communications. Springer Nature, 2019. https://doi.org/10.1038/s41467-019-10490-9. ieee: D. F. Gauto et al., “Integrated NMR and cryo-EM atomic-resolution structure determination of a half-megadalton enzyme complex,” Nature Communications, vol. 10. Springer Nature, 2019. ista: Gauto DF, Estrozi LF, Schwieters CD, Effantin G, Macek P, Sounier R, Sivertsen AC, Schmidt E, Kerfah R, Mas G, Colletier J-P, Güntert P, Favier A, Schoehn G, Schanda P, Boisbouvier J. 2019. Integrated NMR and cryo-EM atomic-resolution structure determination of a half-megadalton enzyme complex. Nature Communications. 10, 2697. mla: Gauto, Diego F., et al. “Integrated NMR and Cryo-EM Atomic-Resolution Structure Determination of a Half-Megadalton Enzyme Complex.” Nature Communications, vol. 10, 2697, Springer Nature, 2019, doi:10.1038/s41467-019-10490-9. short: D.F. Gauto, L.F. Estrozi, C.D. Schwieters, G. Effantin, P. Macek, R. Sounier, A.C. Sivertsen, E. Schmidt, R. Kerfah, G. Mas, J.-P. Colletier, P. Güntert, A. Favier, G. Schoehn, P. Schanda, J. Boisbouvier, Nature Communications 10 (2019). date_created: 2020-09-17T10:28:25Z date_published: 2019-06-19T00:00:00Z date_updated: 2021-01-12T08:19:03Z day: '19' doi: 10.1038/s41467-019-10490-9 extern: '1' external_id: pmid: - '31217444' intvolume: ' 10' keyword: - General Biochemistry - Genetics and Molecular Biology - General Physics and Astronomy - General Chemistry language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.1038/s41467-019-10490-9 month: '06' oa: 1 oa_version: Published Version pmid: 1 publication: Nature Communications publication_identifier: issn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' status: public title: Integrated NMR and cryo-EM atomic-resolution structure determination of a half-megadalton enzyme complex type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 10 year: '2019' ...