Publications de Daniel Patrick Collins

Provably Secure Online Authenticated Encryption and Bidirectional Online Channels

In this work, we examine online authenticated encryption with variable expansion. We follow a notion where both encryption and decryption are online, and security is ensured in the RUP (Release of Unverified Plaintext) setting. Then we propose a generic wa ...

Springer Science and Business Media Deutschland GmbH2025

On the Theory and Practice of Modern Secure Messaging

Daniel Patrick Collins

Billions of people now have conversations daily over the Internet. A large portion of this communication takes place via secure messaging protocols that offer "end-to-end encryption'" guarantees and resilience to compromise like the widely-used Double Ratc ...

EPFL2024

Near Collision Attack Against Grain V1

Willi Meier, Subhadeep Banik, Daniel Patrick Collins

A near collision attack against the Grain v1 stream cipher was proposed by Zhang et al. in Eurocrypt 18. The attack uses the fact that two internal states of the stream cipher with very low hamming distance between them, produce similar keystream sequences ...

2023

Network-Agnostic Security Comes (Almost) for Free in DKG and MPC

Daniel Patrick Collins

Springer2023

On Active Attack Detection in Messaging with Immediate Decryption

Serge Vaudenay, Simone Maria Stefano Colombo, Loïs Evan Huguenin-Dumittan, Khashayar Barooti, Daniel Patrick Collins

Springer2023

Cryptographic Administration for Secure Group Messaging

Serge Vaudenay, Daniel Patrick Collins

Many real-world group messaging systems delegate group administration to the application level, failing to provide formal guarantees related to group membership. Taking a cryptographic approach to group administration can prevent both implementation and pr ...

Berkeley2023

WhatsUpp with Sender Keys? Analysis, Improvements and Security Proofs

Daniel Patrick Collins

Springer2023

Analysis and Improvements of the Sender Keys Protocol for Group Messaging

Daniel Patrick Collins

Messaging between two parties and in the group setting has enjoyed widespread attention both in practice, and, more recently, from the cryptographic community. One of the main challenges in the area is constructing secure (end-to- end encrypted) and effici ...

2022

Optimal Symmetric Ratcheting for Secure Communication

Serge Vaudenay, Andrea Felice Caforio, Daniel Patrick Collins, Hailun Yan

To mitigate state exposure threats to long-lived instant messaging sessions, ratcheting was introduced, which is used in practice in protocols like Signal. However, existing ratcheting protocols generally come with a high cost. Recently, Caforio et al. pro ...

OXFORD UNIV PRESS2022

A Small GIFT-COFB: Lightweight Bit-Serial Architectures

Andrea Felice Caforio, Daniel Patrick Collins

GIFT-COFB is a lightweight AEAD scheme and a submission to the ongoing NIST lightweight cryptography standardization process where it currently competes as a finalist. The construction processes 128-bit blocks with a key and nonce of the same size and has ...

Springer2022

Improving First-Order Threshold Implementations of SKINNY

Andrea Felice Caforio, Ognjen Glamocanin, Subhadeep Banik, Daniel Patrick Collins

Threshold Implementations have become a popular generic technique to construct circuits resilient against power analysis attacks.In this paper, we look to devise efficient threshold circuits for the lightweight block cipher family SKINNY. The only threshol ...

Springer2021

Online Payments by Merely Broadcasting Messages

Rachid Guerraoui, Matej Pavlovic, Dragos-Adrian Seredinschi, Matteo Monti, Athanasios Xygkis, Jovan Komatovic, Daniel Patrick Collins, Andrei Tonkikh

We address the problem of online payments, where users can transfer funds among themselves. We introduce Astro, a system solving this problem efficiently in a decentralized, deterministic, and completely asynchronous manner. Astro builds on the insight tha ...

IEEE2020