---
_id: '14609'
abstract:
- lang: eng
  text: "Distributed Key Generation (DKG) is a technique to bootstrap threshold cryptosystems
    without a trusted party. DKG is an essential building block to many decentralized
    protocols such as randomness beacons, threshold signatures, Byzantine consensus,
    and multiparty computation. While significant progress has been made recently,
    existing asynchronous DKG constructions are inefficient when the reconstruction
    threshold is larger than one-third of the total nodes. In this paper, we present
    a simple and concretely efficient asynchronous DKG (ADKG) protocol among n = 3t
    + 1 nodes that can tolerate up to t malicious nodes and support any reconstruction
    threshold ℓ ≥ t. Our protocol has an expected O(κn3) communication cost, where
    κ is the security parameter, and only assumes the hardness of the Discrete Logarithm.
    The\r\ncore ingredient of our ADKG protocol is an asynchronous protocol to secret
    share a random polynomial of degree ℓ ≥ t, which has other applications, such
    as asynchronous proactive secret sharing and asynchronous multiparty computation.
    We implement our high-threshold ADKG protocol and evaluate it using a network
    of up to 128 geographically distributed nodes. Our evaluation shows that our high-threshold
    ADKG protocol reduces the running time by 90% and bandwidth usage by 80% over
    the state-of-the-art."
acknowledgement: The authors would like to thank Amit Agarwal, Andrew Miller, and
  Tom Yurek for the helpful discussions related to the paper. This work is funded
  in part by a VMware early career faculty grant, a Chainlink Labs Ph.D. fellowship,
  the National Science Foundation, and the Austrian Science Fund (FWF) F8512-N.
article_processing_charge: No
author:
- first_name: Sourav
  full_name: Das, Sourav
  last_name: Das
- first_name: Zhuolun
  full_name: Xiang, Zhuolun
  last_name: Xiang
- first_name: Eleftherios
  full_name: Kokoris Kogias, Eleftherios
  id: f5983044-d7ef-11ea-ac6d-fd1430a26d30
  last_name: Kokoris Kogias
- first_name: Ling
  full_name: Ren, Ling
  last_name: Ren
citation:
  ama: 'Das S, Xiang Z, Kokoris Kogias E, Ren L. Practical asynchronous high-threshold
    distributed key generation and distributed polynomial sampling. In: <i>32nd USENIX
    Security Symposium</i>. Vol 8. Usenix; 2023:5359-5376.'
  apa: 'Das, S., Xiang, Z., Kokoris Kogias, E., &#38; Ren, L. (2023). Practical asynchronous
    high-threshold distributed key generation and distributed polynomial sampling.
    In <i>32nd USENIX Security Symposium</i> (Vol. 8, pp. 5359–5376). Anaheim, CA,
    United States: Usenix.'
  chicago: Das, Sourav, Zhuolun Xiang, Eleftherios Kokoris Kogias, and Ling Ren. “Practical
    Asynchronous High-Threshold Distributed Key Generation and Distributed Polynomial
    Sampling.” In <i>32nd USENIX Security Symposium</i>, 8:5359–76. Usenix, 2023.
  ieee: S. Das, Z. Xiang, E. Kokoris Kogias, and L. Ren, “Practical asynchronous high-threshold
    distributed key generation and distributed polynomial sampling,” in <i>32nd USENIX
    Security Symposium</i>, Anaheim, CA, United States, 2023, vol. 8, pp. 5359–5376.
  ista: Das S, Xiang Z, Kokoris Kogias E, Ren L. 2023. Practical asynchronous high-threshold
    distributed key generation and distributed polynomial sampling. 32nd USENIX Security
    Symposium. USENIX Security Symposium vol. 8, 5359–5376.
  mla: Das, Sourav, et al. “Practical Asynchronous High-Threshold Distributed Key
    Generation and Distributed Polynomial Sampling.” <i>32nd USENIX Security Symposium</i>,
    vol. 8, Usenix, 2023, pp. 5359–76.
  short: S. Das, Z. Xiang, E. Kokoris Kogias, L. Ren, in:, 32nd USENIX Security Symposium,
    Usenix, 2023, pp. 5359–5376.
conference:
  end_date: 2023-08-11
  location: Anaheim, CA, United States
  name: USENIX Security Symposium
  start_date: 2023-08-09
date_created: 2023-11-26T23:00:55Z
date_published: 2023-08-15T00:00:00Z
date_updated: 2023-11-28T09:17:38Z
day: '15'
ddc:
- '000'
department:
- _id: ElKo
file:
- access_level: open_access
  checksum: 1a730765930138e23c6efd2575872641
  content_type: application/pdf
  creator: dernst
  date_created: 2023-11-28T09:14:34Z
  date_updated: 2023-11-28T09:14:34Z
  file_id: '14621'
  file_name: 2023_USENIX_Das.pdf
  file_size: 704331
  relation: main_file
  success: 1
file_date_updated: 2023-11-28T09:14:34Z
has_accepted_license: '1'
intvolume: '         8'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2022/1389
month: '08'
oa: 1
oa_version: Published Version
page: 5359-5376
project:
- _id: 34a4ce89-11ca-11ed-8bc3-8cc37fb6e11f
  grant_number: F8512
  name: Secure Network and Hardware for Efficient Blockchains
publication: 32nd USENIX Security Symposium
publication_identifier:
  isbn:
  - '9781713879497'
publication_status: published
publisher: Usenix
quality_controlled: '1'
scopus_import: '1'
status: public
title: Practical asynchronous high-threshold distributed key generation and distributed
  polynomial sampling
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 8
year: '2023'
...
---
_id: '14735'
abstract:
- lang: eng
  text: "Scaling blockchain protocols to perform on par with the expected needs of
    Web3.0 has been proven to be a challenging task with almost a decade of research.
    In the forefront of the current solution is the idea of separating the execution
    of the updates encoded in a block from the ordering of blocks. In order to achieve
    this, a new class of protocols called rollups has emerged. Rollups have as input
    a total ordering of valid and invalid transactions and as output a new valid state-transition.\r\nIf
    we study rollups from a distributed computing perspective, we uncover that rollups
    take as input the output of a Byzantine Atomic Broadcast (BAB) protocol and convert
    it to a State Machine Replication (SMR) protocol. BAB and SMR, however, are considered
    equivalent as far as distributed computing is concerned and a solution to one
    can easily be retrofitted to solve the other simply by adding/removing an execution
    step before the validation of the input.\r\nThis “easy” step of retrofitting an
    atomic broadcast solution to implement an SMR has, however, been overlooked in
    practice. In this paper, we formalize the problem and show that after BAB is solved,
    traditional impossibility results for consensus no longer apply towards an SMR.
    Leveraging this we propose a distributed execution protocol that allows reduced
    execution and storage cost per executor (O(log2n/n)) without relaxing the network
    assumptions of the underlying BAB protocol and providing censorship-resistance.
    Finally, we propose efficient non-interactive light client constructions that
    leverage our efficient execution protocols and do not require any synchrony assumptions
    or expensive ZK-proofs."
acknowledgement: 'Eleftherios Kokoris-Kogias is partially supported by Austrian Science
  Fund (FWF) grant No: F8512-N.'
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Christos
  full_name: Stefo, Christos
  id: a20e8902-32b0-11ee-9fa8-b23fa638b793
  last_name: Stefo
- first_name: Zhuolun
  full_name: Xiang, Zhuolun
  last_name: Xiang
- first_name: Eleftherios
  full_name: Kokoris Kogias, Eleftherios
  id: f5983044-d7ef-11ea-ac6d-fd1430a26d30
  last_name: Kokoris Kogias
citation:
  ama: 'Stefo C, Xiang Z, Kokoris Kogias E. Executing and proving over dirty ledgers.
    In: <i>27th International Conference on Financial Cryptography and Data Security</i>.
    Vol 13950. Springer Nature; 2023:3-20. doi:<a href="https://doi.org/10.1007/978-3-031-47754-6_1">10.1007/978-3-031-47754-6_1</a>'
  apa: 'Stefo, C., Xiang, Z., &#38; Kokoris Kogias, E. (2023). Executing and proving
    over dirty ledgers. In <i>27th International Conference on Financial Cryptography
    and Data Security</i> (Vol. 13950, pp. 3–20). Bol, Brac, Croatia: Springer Nature.
    <a href="https://doi.org/10.1007/978-3-031-47754-6_1">https://doi.org/10.1007/978-3-031-47754-6_1</a>'
  chicago: Stefo, Christos, Zhuolun Xiang, and Eleftherios Kokoris Kogias. “Executing
    and Proving over Dirty Ledgers.” In <i>27th International Conference on Financial
    Cryptography and Data Security</i>, 13950:3–20. Springer Nature, 2023. <a href="https://doi.org/10.1007/978-3-031-47754-6_1">https://doi.org/10.1007/978-3-031-47754-6_1</a>.
  ieee: C. Stefo, Z. Xiang, and E. Kokoris Kogias, “Executing and proving over dirty
    ledgers,” in <i>27th International Conference on Financial Cryptography and Data
    Security</i>, Bol, Brac, Croatia, 2023, vol. 13950, pp. 3–20.
  ista: 'Stefo C, Xiang Z, Kokoris Kogias E. 2023. Executing and proving over dirty
    ledgers. 27th International Conference on Financial Cryptography and Data Security.
    FC: Financial Cryptography and Data Security, LNCS, vol. 13950, 3–20.'
  mla: Stefo, Christos, et al. “Executing and Proving over Dirty Ledgers.” <i>27th
    International Conference on Financial Cryptography and Data Security</i>, vol.
    13950, Springer Nature, 2023, pp. 3–20, doi:<a href="https://doi.org/10.1007/978-3-031-47754-6_1">10.1007/978-3-031-47754-6_1</a>.
  short: C. Stefo, Z. Xiang, E. Kokoris Kogias, in:, 27th International Conference
    on Financial Cryptography and Data Security, Springer Nature, 2023, pp. 3–20.
conference:
  end_date: 2023-05-05
  location: Bol, Brac, Croatia
  name: 'FC: Financial Cryptography and Data Security'
  start_date: 2023-05-01
date_created: 2024-01-08T09:17:38Z
date_published: 2023-12-01T00:00:00Z
date_updated: 2024-01-08T09:28:14Z
day: '01'
department:
- _id: ElKo
- _id: GradSch
doi: 10.1007/978-3-031-47754-6_1
intvolume: '     13950'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://eprint.iacr.org/2022/1554
month: '12'
oa: 1
oa_version: Preprint
page: 3-20
project:
- _id: 34a4ce89-11ca-11ed-8bc3-8cc37fb6e11f
  grant_number: F8512
  name: Secure Network and Hardware for Efficient Blockchains
publication: 27th International Conference on Financial Cryptography and Data Security
publication_identifier:
  eisbn:
  - '9783031477546'
  eissn:
  - 0302-9743
  isbn:
  - '9783031477539'
  issn:
  - 1611-3349
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Executing and proving over dirty ledgers
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 13950
year: '2023'
...
---
_id: '14829'
abstract:
- lang: eng
  text: 'This paper explores a modular design architecture aimed at helping blockchains
    (and other SMR implementation) to scale to a very large number of processes. This
    comes in contrast to existing monolithic architectures that interleave transaction
    dissemination, ordering, and execution in a single functionality. To achieve this
    we first split the monolith to multiple layers which can use existing distributed
    computing primitives. The exact specifications of the data dissemination part
    are formally defined by the Proof of Availability & Retrieval (PoA &R) abstraction.
    Solutions to the PoA &R problem contain two related sub-protocols: one that “pushes”
    information into the network and another that “pulls” this information. Regarding
    the latter, there is a dearth of research literature which is rectified in this
    paper. We present a family of pulling sub-protocols and rigorously analyze them.
    Extensive simulations support the theoretical claims of efficiency and robustness
    in case of a very large number of players. Finally, actual implementation and
    deployment on a small number of machines (roughly the size of several industrial
    systems) demonstrates the viability of the architecture’s paradigm.'
acknowledgement: 'This work is partially supported by Meta. Eleftherios Kokoris-Kogias
  is partially supported by Austrian Science Fund (FWF) grant No: F8512-N. Shir Cohen
  is supported by the Adams Fellowship Program of the Israel Academy of Sciences and
  Humanities.'
alternative_title:
- LNCS
article_processing_charge: No
author:
- first_name: Shir
  full_name: Cohen, Shir
  last_name: Cohen
- first_name: Guy
  full_name: Goren, Guy
  last_name: Goren
- first_name: Eleftherios
  full_name: Kokoris Kogias, Eleftherios
  id: f5983044-d7ef-11ea-ac6d-fd1430a26d30
  last_name: Kokoris Kogias
- first_name: Alberto
  full_name: Sonnino, Alberto
  last_name: Sonnino
- first_name: Alexander
  full_name: Spiegelman, Alexander
  last_name: Spiegelman
citation:
  ama: 'Cohen S, Goren G, Kokoris Kogias E, Sonnino A, Spiegelman A. Proof of availability
    and retrieval in a modular blockchain architecture. In: <i>27th International
    Conference on Financial Cryptography and Data Security</i>. Vol 13951. Springer
    Nature; 2023:36-53. doi:<a href="https://doi.org/10.1007/978-3-031-47751-5_3">10.1007/978-3-031-47751-5_3</a>'
  apa: 'Cohen, S., Goren, G., Kokoris Kogias, E., Sonnino, A., &#38; Spiegelman, A.
    (2023). Proof of availability and retrieval in a modular blockchain architecture.
    In <i>27th International Conference on Financial Cryptography and Data Security</i>
    (Vol. 13951, pp. 36–53). Bol, Brac, Croatia: Springer Nature. <a href="https://doi.org/10.1007/978-3-031-47751-5_3">https://doi.org/10.1007/978-3-031-47751-5_3</a>'
  chicago: Cohen, Shir, Guy Goren, Eleftherios Kokoris Kogias, Alberto Sonnino, and
    Alexander Spiegelman. “Proof of Availability and Retrieval in a Modular Blockchain
    Architecture.” In <i>27th International Conference on Financial Cryptography and
    Data Security</i>, 13951:36–53. Springer Nature, 2023. <a href="https://doi.org/10.1007/978-3-031-47751-5_3">https://doi.org/10.1007/978-3-031-47751-5_3</a>.
  ieee: S. Cohen, G. Goren, E. Kokoris Kogias, A. Sonnino, and A. Spiegelman, “Proof
    of availability and retrieval in a modular blockchain architecture,” in <i>27th
    International Conference on Financial Cryptography and Data Security</i>, Bol,
    Brac, Croatia, 2023, vol. 13951, pp. 36–53.
  ista: 'Cohen S, Goren G, Kokoris Kogias E, Sonnino A, Spiegelman A. 2023. Proof
    of availability and retrieval in a modular blockchain architecture. 27th International
    Conference on Financial Cryptography and Data Security. FC: Financial Cryptography
    and Data Security, LNCS, vol. 13951, 36–53.'
  mla: Cohen, Shir, et al. “Proof of Availability and Retrieval in a Modular Blockchain
    Architecture.” <i>27th International Conference on Financial Cryptography and
    Data Security</i>, vol. 13951, Springer Nature, 2023, pp. 36–53, doi:<a href="https://doi.org/10.1007/978-3-031-47751-5_3">10.1007/978-3-031-47751-5_3</a>.
  short: S. Cohen, G. Goren, E. Kokoris Kogias, A. Sonnino, A. Spiegelman, in:, 27th
    International Conference on Financial Cryptography and Data Security, Springer
    Nature, 2023, pp. 36–53.
conference:
  end_date: 2023-05-05
  location: Bol, Brac, Croatia
  name: 'FC: Financial Cryptography and Data Security'
  start_date: 2023-05-01
date_created: 2024-01-18T07:41:12Z
date_published: 2023-12-01T00:00:00Z
date_updated: 2024-01-22T13:58:07Z
day: '01'
department:
- _id: ElKo
doi: 10.1007/978-3-031-47751-5_3
intvolume: '     13951'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://fc23.ifca.ai/preproceedings/150.pdf
month: '12'
oa: 1
oa_version: Submitted Version
page: 36-53
project:
- _id: 34a4ce89-11ca-11ed-8bc3-8cc37fb6e11f
  grant_number: F8512
  name: Secure Network and Hardware for Efficient Blockchains
publication: 27th International Conference on Financial Cryptography and Data Security
publication_identifier:
  eisbn:
  - '9783031477515'
  eissn:
  - 1611-3349
  isbn:
  - '9783031477508'
  issn:
  - 0302-9743
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Proof of availability and retrieval in a modular blockchain architecture
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 13951
year: '2023'
...