Joop Van De Pol

This blog post describes how electronic passports work, the threats within their threat model, and how they protect against those threats using cryptography. It also discusses the implications of using electronic passports for novel applications, such as zero-knowledge identity proofs.

In October 2023, we audited Silence Laboratories’ DKLs23 threshold signature scheme (TSS) library—one of the first production implementations of this then-novel protocol that uses oblivious transfer (OT) instead of traditional Paillier cryptography. Our review uncovered serious flaws that could enable key destruction attacks, which Silence Laboratories promptly fixed.

This post will examine the cryptography behind passkeys, the guarantees they do or do not give, and interesting cryptographic things you can do with them, such as generating cryptographic keys and storing certificates.

In October 2023, Ockam hired Trail of Bits to review the design of its product, a set of protocols that aims to enable secure communication (i.e., end-to-end encrypted and mutually authenticated channels) across various heterogeneous networks. A secure system starts at the design […]

Trusted execution environments (TEE) such as secure enclaves are becoming more popular to secure assets in the cloud. Their promise is enticing because when enclaves are properly used, even the operator of the enclave or the cloud service should not be able to access those assets. However, this leads to […]

We found a vulnerability in a threshold signature scheme that allows an attacker to recover the signing key of threshold ECDSA implementations that are based on Oblivious Transfer (OT). A malicious participant of the threshold signing protocols could perform selective abort attacks during the OT extension subprotocol, recover the secret […]