Cryptography FM

On April 19th 2022, Neil Madden disclosed a vulnerability in many popular Java runtimes and development kits. The vulnerability, dubbed "Psychic Signatures", lies in the cryptography for ECDSA signatures and allows an attacker to bypass signature checks entirely for these signatures. How are popular cryptographic protocol implementations in Java affected? What's the state of Java cryptography as a whole? Join Neil, Nadim and Lucas as they discuss. Music composed by Yasunori Mitsuda. Special Guest: Neil Madden.

Threema is a Swiss encrypted messaging application. It has more than 10 million users and more than 7000 on-premise customers. Prominent users of Threema include the Swiss Government and the Swiss Army, as well as the current Chancellor of Germany, Olaf Scholz. Threema has been widely advertised as a secure alternative to other messengers. Kenny, Kien and Matteo from the ETH Zurich Applied Cryptography Group present seven attacks against the cryptographic protocols used by Threema, in three distinct threat models. All the attacks are accompanied by proof-of-concept implementations that demonstrate their feasibility in practice. Links and papers discussed in the show: * Three Lessons from Threema (https://breakingthe3ma.app/) Special Guests: Kenny Paterson, Kien Tuong Truong, and Matteo Scarlata.

Benjamin Wesolowski talks about his latest paper in which he mathematically proved that the two fundamental problems underlying isogeny-based cryptography are equivalent. Links and papers discussed in the show: * The supersingular isogeny path and endomorphism ring problems are equivalent (https://eprint.iacr.org/2021/919) * Episode 5: Isogeny-based Cryptography for Dummies! (https://www.cryptography.fm/5) Music composed by Toby Fox and performed by Sean Schafianski (https://seanschafianski.bandcamp.com/). Special Guest: Benjamin Wesolowski.

A team of cryptanalysits presents the first publicly available cryptanalytic attacks on the GEA-1 and GEA-2 algorithms. Instead of providing full 64-bit security, they show that the initial state of GEA-1 can be recovered from as little as 65 bits of known keystream (with at least 24 bits coming from one frame) in time 240 GEA-1 evaluations and using 44.5 GiB of memory. The attack on GEA-1 is based on an exceptional interaction of the deployed LFSRs and the key initialization, which is highly unlikely to occur by chance. This unusual pattern indicates that the weakness is intentionally hidden to limit the security level to 40 bit by design. Cryptanalysis of the GPRS Encryption Algorithms GEA-1 and GEA-2 (https://eprint.iacr.org/2021/819) Music composed by Toby Fox and performed by Sean Schafianski (https://seanschafianski.bandcamp.com/). Special Guests: Gaëtan Leurent and Håvard Raddum.