Saving peace in Europe Using MPC Carsten Baum Aarhus University.
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Transcript of Saving peace in Europe Using MPC Carsten Baum Aarhus University.
![Page 1: Saving peace in Europe Using MPC Carsten Baum Aarhus University.](https://reader034.fdocuments.net/reader034/viewer/2022051619/56649e7c5503460f94b7e43e/html5/thumbnails/1.jpg)
Saving peace in Europe
Using MPC
Carsten Baum Aarhus University
![Page 2: Saving peace in Europe Using MPC Carsten Baum Aarhus University.](https://reader034.fdocuments.net/reader034/viewer/2022051619/56649e7c5503460f94b7e43e/html5/thumbnails/2.jpg)
After the first half of the 20th century, we Europeans had enough…
Enough of these wars! Let‘s all be peaceful and happy.
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Approach #1
Футбол, fútbol, Fußball, fodbold, ποδόσφαιρο, calcio, …
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Well, that did not work…
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Approach #2: Let‘s all sing!
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What is Eurovision?
• Big TV event (this Saturday!!)
• How it works:1. Every country is allowed to
send someone to present a song
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What is Eurovision?
• Big TV event (this Saturday!!)
• How it works:1. Every country is allowed to
send someone to present a song
2. Big Europe-wide vote afterwards to determine who won
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Vote you say??
• 21st century approach: Online voting!
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Vote you say??
• 21st century approach: Online voting!
• Using MPC for voting gives advantages in some scenarios (see paper)
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Vote you say??
• 21st century approach: Online voting!
• Using MPC for voting gives advantages in some scenarios (see paper)
• For example, use a fast online protocol (SPDZ) to obtain the answer very quickly
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MPC needs Audit
Because…do you really trust any of the participating countries???
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Publicly Auditable MPC – the model
• Clients: Provide input and will obtain output
• Workers: Do the actual computation
• The Auditor: Checks whether the computation was correct
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Publicly Auditable MPC – the model
Downside:• If every party is corrupted, privacy is lost
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Publicly Auditable MPC – the model
Downside:• If every party is corrupted, privacy is lost
BUT:• The Auditor (anyone!) can establish correctness (by
looking at the π-transcript) even if every Worker is corrupted
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Publicly Auditable MPC – the model
Downside:• If every party is corrupted, privacy is lost
BUT:• The Auditor (anyone!) can establish correctness (by
looking at the π-transcript) even if every Worker is corrupted
• If at least one Worker is honest, then we obtain both privacy and correctness
![Page 16: Saving peace in Europe Using MPC Carsten Baum Aarhus University.](https://reader034.fdocuments.net/reader034/viewer/2022051619/56649e7c5503460f94b7e43e/html5/thumbnails/16.jpg)
Publicly Auditable MPC – the model
• We model this by assuming the existence of an uncorruptible party
• This party does not participate during the π-execution
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Publicly Auditable MPC – the model
• We model this by assuming the existence of an uncorruptible party
• This party does not participate during the π-execution
• In fact, it must not even exist until π was executed
![Page 18: Saving peace in Europe Using MPC Carsten Baum Aarhus University.](https://reader034.fdocuments.net/reader034/viewer/2022051619/56649e7c5503460f94b7e43e/html5/thumbnails/18.jpg)
Publicly Auditable MPC – the model
• We model this by assuming the existence of an uncorruptible party
• This party does not participate during the π-execution
• In fact, it must not even exist until π was executed
• This is a generalization of „public verifiability“ for online voting, but here for general MPC
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Publicly Auditable MPC as a SPDZ extension
• Extension of the SPDZ online phase – but (almost) no heavy crypto required
• Extend the SPDZ preprocessing as well (must also be auditable, and indeed is)
• (optional) Audit phase if you doubt that the result is correct
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eprint 2014/075More details:
„Publicly Auditable Secure Multi-Party Computation“
(joint work with Ivan Damgård and Claudio Orlandi)