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A Distributed Public Key Infrastructure for the Web Backed by a Blockchain
KTH, School of Computer Science and Communication (CSC).
2017 (English)Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesisAlternative title
En distribuerad publik nyckel-infrastruktur för webben uppbackad av en blockkedja (Swedish)
Abstract [en]

The thesis investigates how a blockchain can be used to build a decentralised public key infrastructure for the web, by proposing a custom federation blockchain relying on honest majority. Our main contribution is the design of a Proof of Stake protocol based on a stake tree, which builds upon an idea called follow-the-satoshi used in previous papers.

Digital identities are stored in an authenticated self-balancing tree maintained by blockchain nodes. Our back-of-the-envelope calculations, based on the size of the domain name system, show that the block size must be set to at least 5.2 MB, while each blockchain node with a one-month transaction history would need to store about 243 GB. Thin clients would have to synchronise about 13.6 MB of block headers per year, and download an additional 3.7 KB of proof data for every leaf certificate which is to be checked.

Abstract [sv]

Uppsatsen undersöker hur en blockkedja kan användas för att bygga en decentraliserad publik nyckel-infrastruktur för webben. Vi ger ett designförslag på en blockkedja som drivs av en pålitlig grupp av noder, där en majoritet antas vara ärliga. Vårt huvudsakliga bidrag är utformningen av ett Proof of Stake-protokoll baserat på ett staketräd, vilket bygger på en idé som kallas follow-the-satoshi omnämnd i tidigare publikationer.

Digitala identiteter sparas i ett autentiserat, självbalanserande träd som underhålls av noder anslutna till blockkedjenätverket. Våra preliminära beräkningar baserade på storleken av DNS-systemet visar att blockstorleken måste sättas till åtminstone 5.2 MB, medan varje nod med en månads transaktionshistorik måste spara ungefär 243 GB. Webbläsare och andra resurssnåla klienter måste synkronisera 13.6 MB data per år, och ladda ner ytterligare 3.7 KB för varje användarcertifikat som skall valideras.

Place, publisher, year, edition, pages
2017.
Keywords [en]
Public key infrastructure, Blockchain, Merkle tree, Proof of Stake, Certificate authority
National Category
Computer Sciences
Identifiers
URN: urn:nbn:se:kth:diva-210912OAI: oai:DiVA.org:kth-210912DiVA, id: diva2:1121040
External cooperation
PrimeKey Solutions AB
Educational program
Master of Science in Engineering - Computer Science and Technology
Presentation
2017-06-15, 4618, Lindstedtsvägen 5, Stockholm, 13:37 (English)
Supervisors
Examiners
Available from: 2017-09-19 Created: 2017-07-08 Last updated: 2018-01-13Bibliographically approved

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CiteExportLink to record
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