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

Abstract:

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).

Authors:

Ethan Heilman, Boston University
Neha Narula, MIT Media Lab, Digital Currency Initiative
Garrett Tanzer, Harvard University
James Lovejoy, MIT Media Lab, Digital Currency Initiative
Michael Colavita, Harvard University
Madars Virza, MIT Media Lab, Digital Currency Initiative
Thaddeus “Tadge” Dryja, MIT Media Lab, Digital Currency Initiative