Filters








799 Hits in 7.6 sec

The Leverage Ratchet Effect

Anat R. Admati, Peter M. DeMarzo, Martin F. Hellwig, Paul C. Pfleiderer
2013 Social Science Research Network  
Firms' inability to commit to future funding choices has profound consequences for capital structure dynamics.  ...  These asymmetric forces in leverage adjustments, which we call the leverage ratchet effect, cause equilibrium leverage outcomes to be history-dependent.  ...  Concluding Remarks Our paper's most important message is that the observed funding mixes of corporations are unlikely to be explained by an optimal initial contracting decision followed by a sequence of  ... 
doi:10.2139/ssrn.2311197 fatcat:yjpnwdclcrcgrjkdmmcuauhr7i

The Leverage Ratchet Effect

Anat R. Admati, Peter M. DeMarzo, Martin F. Hellwig, Paul C. Pfleiderer
2013 Social Science Research Network  
Firms' inability to commit to future funding choices has profound consequences for capital structure dynamics.  ...  These asymmetric forces in leverage adjustments, which we call the leverage ratchet effect, cause equilibrium leverage outcomes to be history-dependent.  ...  Concluding Remarks Our paper's most important message is that the observed funding mixes of corporations are unlikely to be explained by an optimal initial contracting decision followed by a sequence of  ... 
doi:10.2139/ssrn.2304969 fatcat:i2z75ipwbfajlluqcrfyxyucpy

A More Complete Analysis of the Signal Double Ratchet Algorithm [article]

Alexander Bienstock, Jaiden Fairoze, Sanjam Garg, Pratyay Mukherjee, Srinivasan Raghuraman
2022 IACR Cryptology ePrint Archive  
[CRYPTO 2020] for Secure Group Messaging.  ...  Signal Double Ratchet (DR for short) algorithm.  ...  Acknowledgements We would like to thank Yevgeniy Dodis and Daniel Jost for helping us realize that the trick used in the CKA + construction can also be used to make UPKE more efficient (Section 7).  ... 
dblp:journals/iacr/BienstockFGMR22 fatcat:3zmlphylzbh2pcz45fixacbjc4

Systemic Risk and the Refinancing Ratchet Effect

Amir E. Khandani, Andrew W. Lo, Robert C. Merton
2009 Social Science Research Network  
The refinancing ratchet effect is a new type of systemic risk in the financial system and does not rely on any dysfunctional behaviors.  ...  The combination of rising home prices, declining interest rates, and near-frictionless refinancing opportunities can create unintentional synchronization of homeowner leverage, leading to a "ratchet" effect  ...  By the last quarter of 2008, this sensitivity almost doubled to $38.13 billion for each 1% drop in home values.  ... 
doi:10.2139/ssrn.1472892 fatcat:jymddl2gtnaqtlazkfb4ci7yvm

Keep the Dirt: Tainted TreeKEM, an Efficient and Provably Secure Continuous Group Key Agreement Protocol [article]

Joël Alwen, Margarita Capretto, Miguel Cueto, Chethan Kamath, Karen Klein, Guillermo Pascual-Perez, Krzysztof Pietrzak, Michael Walter
2019 IACR Cryptology ePrint Archive  
While messaging systems with strong security guarantees are widely used in practice, designing a protocol that scales efficiently to large groups and enjoys similar security guarantees remains largely  ...  The two existing proposals to date are ART CCS18) and TreeKEM (IETF, The Messaging Layer Security Protocol, draft).  ...  "Message Layer Security" working group.  ... 
dblp:journals/iacr/AlwenCCKKPPW19 fatcat:lsnjr27ovbdwnn43jcmn6bxv7e

A Concrete Treatment of Efficient Continuous Group Key Agreement via Multi-Recipient PKEs

Keitaro Hashimoto, Shuichi Katsumata, Eamonn Postlethwaite, Thomas Prest, Bas Westerbaan
2021 Proceedings of the 2021 ACM SIGSAC Conference on Computer and Communications Security  
Continuous group key agreements (CGKAs) are a class of protocols that can provide strong security guarantees to secure group messaging protocols such as Signal and MLS.  ...  Our experiments show that even for groups with a size as large as N = 2 10 , commit messages can be computed and processed in less than 100 ms.  ...  This motivates the need for CGKA protocols and post-quantum primitives that remain efficient and secure for large groups.  ... 
doi:10.1145/3460120.3484817 fatcat:cs2vbx7ounf4bodxhifag3wzta

Server-Aided Continuous Group Key Agreement [article]

Joël Alwen, Dominik Hartmann, Eike Kiltz, Marta Mularczyk
2021 IACR Cryptology ePrint Archive  
Continuous Group Key Agreement (CGKA) -or Group Ratcheting -lies at the heart of a new generation of End-to-End (E2E) secure group messaging (SGM) and VoIP protocols supporting very large groups.  ...  Next, we provide a simple and intuitive security model for saCGKA.  ...  While in most applications q = 2 is optimal, choosing q > 2 is more efficient if SAIK is instantiated with (an mmPKE built from) a post-quantum secure mKEM [46] . Ratchet tree evolution.  ... 
dblp:journals/iacr/AlwenHKM21 fatcat:lfqupvsmejawfkzxj2qge6opxi

On The Insider Security of MLS [article]

Joël Alwen, Daniel Jost, Marta Mularczyk
2020 IACR Cryptology ePrint Archive  
The Messaging Layer Security (MLS) protocol is a new complex open standard for end-to-end (E2E) secure group messaging being developed by the IETF.  ...  Its primary security goal is to provide E2E privacy and authenticity for messages in long lived sessions whenever possible.  ...  For instance, RTreeKEM [1] improves this with almost no efficiency loss. -One encryption key per key package.  ... 
dblp:journals/iacr/AlwenJM20 fatcat:5k5bwh3x2zh4rgbwaxewuae6c4

Consistent Synchronous Group Off-The-Record Messaging with SYM-GOTR

Michael Schliep, Eugene Vasserman, Nicholas Hopper
2018 Proceedings on Privacy Enhancing Technologies  
We describe SYM-GOTR, a protocol for secure Group Off-The-Record (GOTR) messaging.  ...  and the guarantee that all users see the same conversation, while providing efficient use of network and CPU resources.  ...  during secure channel set up; KDF 2 : (G, U, U ) → {0, 1} l for key ratcheting; and finally, KDF 3 : {0, 1} * → {0, 1} l for broadcast message keys.  ... 
doi:10.1515/popets-2018-0027 dblp:journals/popets/SchliepVH18 fatcat:cypqlbggxvdbtfuzlh45ouilu4

ASAP: Algorithm Substitution Attacks on Cryptographic Protocols [article]

Sebastian Berndt, Jan Wichelmann, Claudius Pott, Tim-Henrik Traving, Thomas Eisenbarth
2020 IACR Cryptology ePrint Archive  
In contrast, Signal's double-ratchet protocol shows higher immunity to ASAs, as the leakage requires much more messages.  ...  The security of digital communication relies on few cryptographic protocols that are used to protect internet traffic, from web sessions to instant messaging.  ...  This also matches the security guarantee of Theorem 2 which only guarantees security for sufficiently long randomness.  ... 
dblp:journals/iacr/BerndtWPTE20 fatcat:vjmaha7v65ftvfkdat5vndoujm

Xoodyak, a lightweight cryptographic scheme

Joan Daemen, Seth Hoffert, Michaël Peeters, Gilles Van Assche, Ronny Van Keer
2020 IACR Transactions on Symmetric Cryptology  
For those use cases, we translate the relatively detailed security claim that we make for Xoodyak into simple ones.  ...  Internally, it uses the Xoodoo[12] permutation that, with its width of 48 bytes, allows for very compact implementations.  ...  Acknowledgments We thank Frederik Armknecht and anonymous reviewers of ToSC editorial board for their suggestions improving the editorial quality of this paper.  ... 
doi:10.13154/tosc.v2020.is1.60-87 dblp:journals/tosc/DaemenHPAK20 fatcat:zpgfemwxf5cljcetkxbwlczsem

Secure Group Communication [chapter]

2008 Information Assurance  
However, many of the protocols do not provide provable security and do not provide other security guarantees about the conversation.  ...  I propose two private group messing protocols with provable privacy properties for two networking models; online instant messaging, and mobile messaging.  ...  The simulator is almost identical to the simulator for participant repudiation.  ... 
doi:10.1016/b978-012373566-9.50019-7 fatcat:2dj4z3pwa5foxmaw5chnwdmzxu

Practical (Post-Quantum) Key Combiners from One-Wayness and Applications to TLS [article]

Nimrod Aviram, Benjamin Dowling, Ilan Komargodski, Kenneth G. Paterson, Eyal Ronen, Eylon Yogev
2022 IACR Cryptology ePrint Archive  
We believe that our approach exemplifies a perfect middleground for practically efficient constructions that are supported by realistic hardness assumptions.  ...  From an analytical standpoint, current security proofs model such key combiners as dual-PRFs -a function which is a PRF when keyed by either of its two inputs -guaranteeing pseudo-randomness if one of  ...  : thus, HKDF.Extract and KeyCombine provide no guarantees on the security of the output ES (resp.  ... 
dblp:journals/iacr/AviramDKPRY22 fatcat:6vtfrp6aa5bhdfgbm55byaxoam

Algorithms for Lightweight Key Exchange †

Rafael Alvarez, Cándido Caballero-Gil, Juan Santonja, Antonio Zamora
2017 Sensors  
Some secure protocols, especially those that enable forward secrecy, make a much heavier use of public-key cryptography, increasing the demand for lightweight cryptosystems that can be implemented in low  ...  We benchmark several public-key key-exchange algorithms, determining those that are better for the requirements of critical infrastructure and emergency applications and propose a security framework based  ...  Caballero-Gil and Santonja focused on the cryptographic primitive analysis while Alvarez and Zamora focused on the security framework and overall research and experiment revision.  ... 
doi:10.3390/s17071517 pmid:28654006 pmcid:PMC5551094 fatcat:flpdvvq4bfcupn2ralx2hiptbq

Clarion: Anonymous Communication from Multiparty Shuffling Protocols [article]

Saba Eskandarian, Dan Boneh
2021 IACR Cryptology ePrint Archive  
We implement our shuffling protocol in a system called Clarion and find that it outperforms a mixnet made up of a sequence of verifiable (single-server) shuffles by 9.2× for broadcasting small messages  ...  This paper studies the role of multiparty shuffling protocols in enabling more efficient metadatahiding communication.  ...  ACKNOWLEDGMENTS We would like to thank our shepherd Pedro Moreno-Sanchez for helpful comments in preparing the final version of this paper.  ... 
dblp:journals/iacr/EskandarianB21 fatcat:lgwi6prkmfhvnlt435r4pkx7qu
« Previous Showing results 1 — 15 out of 799 results