Tokenless

Cryptography

Designing safe digital systems for the humanitarian sector

Designing safe digital systems for the humanitarian sector

Carmela Troncoso from EPFL discusses her collaboration with the International Committee of the Red Cross (ICRC) to digitalize humanitarian aid distribution. She advocates for a paradigm shift from data minimization to "purpose limitation," designing systems that are structurally incapable of being misused, even if the data is accessed. The talk details a practical, low-cost, and connectivity-resilient system built on this principle, using smart cards and cryptographic techniques to protect vulnerable aid recipients while meeting the operational needs of the ICRC.

Lattice-Based Accumulator and Application to Anonymous Credential Revocation

Lattice-Based Accumulator and Application to Anonymous Credential Revocation

Victor Youdom Kemmoe from Brown University presents a novel, communication-efficient cryptographic accumulator based on the Module-SIS assumption. This construction is designed for applications like anonymous credential revocation, where elements can be added without needing to update existing membership witnesses, a significant improvement over previous post-quantum schemes.

Efficient Secure Aggregation for Federated Learning

Efficient Secure Aggregation for Federated Learning

Varun Madathil from Yale University presents Tacita, a novel, single-server protocol for secure aggregation in Federated Learning (FL). Tacita is designed to address the unique constraints of the FL environment, such as client dropouts and the absence of client-to-client communication. The protocol achieves one-shot execution with constant-size communication and robustness against dropouts by introducing two new cryptographic primitives: succinct multi-key linearly homomorphic threshold signatures (MKLHTS) and a homomorphic variant of Silent Threshold Encryption.

zk-promises: Anonymous Moderation, Reputation, & Blocking from Anonymous Credentials with Callbacks

zk-promises: Anonymous Moderation, Reputation, & Blocking from Anonymous Credentials with Callbacks

A novel framework called zk-promises is introduced, enabling stateful anonymous credentials with Turing-complete state machines and asynchronous callbacks. This allows for robust moderation, such as banning or reputation updates, for anonymous users without compromising their privacy, using zk-objects and zero-knowledge proofs to ensure state integrity.

Encrypted Computation: What if Decryption Wasn’t Needed? • Katharine Jarmul • GOTO 2024

Encrypted Computation: What if Decryption Wasn’t Needed? • Katharine Jarmul • GOTO 2024

An exploration of encrypted computation, detailing how techniques like homomorphic encryption and multi-party computation can enable machine learning on encrypted data. The summary covers the core mathematical principles, real-world use cases, and open-source libraries to build more private and trustworthy AI systems.

The Unofficial Guide to Apple’s Private Cloud Compute - Jonathan Mortensen, CONFSEC

The Unofficial Guide to Apple’s Private Cloud Compute - Jonathan Mortensen, CONFSEC

A technical deep dive into Apple's Private Cloud Compute (PCC), exploring its novel architecture for running sensitive AI workloads with cryptographic privacy guarantees. The talk covers the core requirements, key components like remote attestation and transparency logs, and how these concepts can be applied by developers today.