Posts tagged Tadge Dryja
Utreexo: A dynamic hash-based accumulator optimized for the Bitcoin UTXO set

by Thaddeus Dryja (MIT’s Digital Currency Initiative)

AbstractIn the Bitcoin consensus network, all nodes come to agreement on the set of Unspent Transaction Outputs (The “UTXO” set). The size of this shared state is a scalability constraint for the network, as the size of the set expands as more users join the system, increasing resource requirements of all nodes. Decoupling the network’s state size from the storage requirements of individual machines would reduce hardware requirements of validating nodes. We introduce a hash based accumulator to locally represent the UTXO set, which is logarithmic in the size of the full set. Nodes attach and propagate inclusion proofs to the inputs of transactions, which along with the accumulator state, give all the information needed to validate a transaction. While the size of the inclusion proofs results in an increase in network traffic, these proofs can be discarded after verification, and aggregation methods can reduce their size to a manageable level of overhead. In our simulations of downloading Bitcoin’s blockchain up to early 2019 with 500MB of RAM allocated for caching, the proofs only add approximately 25% to the amount otherwise downloaded.

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Cryptanalysis of Curl-P and Other Attacks on the IOTA Cryptocurrency

By Ethan Heilman (Boston Uni), Neha Narula (MIT Media Lab), Garrett Tanzer (Harvard), James Lovejoy (MIT Media Lab), Michael Colavita (Harvard), Madars Virza (MIT Media Lab), and Tadge Dryja (MIT Media Lab)

We present attacks on the cryptography formerly used in the IOTA blockchain, including under certain conditions the ability to forge signatures. We developed practical attacks on IOTA’s cryptographic hash function Curl-P-27, allowing us to quickly generate short colliding messages. These collisions work even for messages of the same length. Exploiting these weaknesses in Curl-P-27, we broke the EU-CMA security of the former IOTA Signature Scheme (ISS). Finally, we show that in a chosen-message setting we could forge signatures and multi-signatures of valid spending transactions (called bundles in IOTA).

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Coindesk's 'This Scaling Tech Could Let You Sync Bitcoin Straight From Your Phone' using UTreeXO created by Tadge Dryja

“Maybe we don’t have to store everything ourselves.”

That’s Tadge Dryja, cryptocurrency research scientist at the MIT Digital Currency Initiative, explaining the concept behind his bitcoin scaling solution, “utreexo.”

Based on an idea that has been pursued by developers for many years, utreexo seeks to streamline an aspect of bitcoin’s code that leads to heavy storage requirements over time.

Read the original article here

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Coindesk's 'Bitcoin at 10[years old]': From Fearing Bitcoin To Fixing Its Worst Problem: Tadge Dryja

A celebration of 10 years of Bitcoin features DCI's Tadge Dryja story:

““I thought I would go to jail.”

That’s why Tadge Dryja, one of two principal researchers who would go on to envision lightning – what has become arguably the most important innovation in the quest to bring bitcoin to the masses – kept his passion for the technology to himself when he first heard about it in 2011.”

Read the article on Coindesk here

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