[crypto] Fwd: [risc-list] RISC at CWI (Thu Oct 5): Esteban Landerreche

[R. Hirschfeld]

-------- Original Message --------
Subject: [risc-list] RISC at CWI (Thu Oct 5): Esteban Landerreche
Date: 2017-09-28 12:00
 From: "Marc Stevens" <Marc.Stevens at cwi.nl>
To: <risc-list at cwi.nl>

Dear Colleagues,



we cordially invite you to to a RISC Seminar taking place at CWI



          * Thursday October 5th, 2017, from 15:00 to 16:00 *

                 * in CWI, Amsterdam, Room L017 *



Talk:

Esteban Landerreche, Institute for Logic, Language and Computation,
Universiteit van Amsterdam

*Leaning on Impossible-to-Parallelise Work for Immutability Guarantees 
in
the Blockchain*



Abstract:

Blockchains are structures that allow to establish trust by relying on
cryptographic primitives to ensure that the information encoded in them
cannot be changed. Bitcoin is the first example of a blockchain and an
important amount of the research is concerned with replicating its
advantages in other settings. Another avenue of research focuses on
improving on the flaws of Bitcoin, like how it incentivises 
parallelisation
and is vulnerable to quantum attacks. An important limitation of Bitcoin 
is
that its immutability guarantees can only be maintained in a large 
network
at a large cost, making it unusable for many applications. In this work, 
we
present a blockchain protocol that avoids these issues by ensuring
immutability through proofs of work based on \emph{sequential 
computation}.
By separating the proofs of work from the consensus mechanism, we avoid 
the
incentives for parallelisation found in Bitcoin while maintaining 
similar
guarantees that the information contained within cannot be changed. 
First,
we present the security guarantees that serial proofs of work contribute 
to
the blockchain structure. We then construct a protocol in a modular way
through the universal composability framework in an idealised setting 
and
prove that it is secure. Next, we get rid of many of the idealising
assumptions and show that our model is still secure. Finally, we 
introduce a
new setting for the use of blockchains, with peers maintaining personal
blockchains that form a web of trust. We believe that the models 
presented
in this work will be able to replicate the immutability guarantees of
Bitcoin in a permissioned setting while avoiding some of the setbacks of
that model.



For more information, see our RISC webpage:

https://projects.cwi.nl/crypto/risc.php



See you then and there!



Best regards,

Marc Stevens


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