Articles by Laurent Grémy

In the first part of the blogpost, we tackled the issue of 1v1 conversations, and it is now time to see how this applies to 1vMANY: group chats! We will give an overview of current solutions, and then have a look at the Messaging Layer Security working group.

Today's communications are, as frequently requested by users, more and more secure. In this first part of the blogpost, we will detail some key features of instant messaging applications, in the setting where (only) two parties want to communicate.

The Litecoin Foundation mandated Quarkslab to audit the implementation of the MimbleWimble protocol in the Litecoin blockchain. This protocol acts as a sidechain in which privacy of the transactions is improved compared to the privacy on the classical chain.

Post-quantum cryptography is an active field of research, especially since the NIST Call for Submissions in 2016 to design new standards for asymmetric key cryptography. The aim of post-quantum cryptography is to mitigate the risk of a large-scale quantum computer which may break all the asymmetric cryptography that is deployed today. This blogpost will present the activity state of the post-quantum cryptography field and sketch the challenges for the deployment of post-quantum safe standards for the industry, both in term of internal infrastructures and security products.

The Ethereum Foundation mandated Quarkslab to perform an audit of the herumi libraries. They provide an API to perform BLS signatures, one of the core components of the new iteration of the Ethereum blockchain, named Ethereum 2.0. While reviewing the architecture of these libraries, their back ends and the adherence with the ongoing RFCs to standardize BLS signature usage, we found some issues primarily regarding their design. Although these are not considered critical, they impact the overall reliability of the libraries. We provide recommendations to improve the design of the libraries, the readability of the code and the usability of both projects.

The Tari Labs mandated Quarkslab to perform a cryptographic and security assessment of the dalek libraries. One of the Tari Labs' projects is to implement the Tari protocol, a decentralised assets protocol. It relies on some of the dalek libraries, especially the cryptographic primitives, provided by subtle and curve25519-dalek. Moreover, the use of Bulletproofs [6], and its implementation by the authors of the dalek libraries, will allow them to enable efficient confidential transactions on the blockchain in a near future.

We only found some minor issues. We also provided recommendations on the usage of the libraries and third-party libraries.

Quarkslab's team performed a cryptographic and security assessment of the Monero Research Lab’s new Proof-of-Work algorithm, called RandomX [1]. RandomX is a proof-of-work algorithm that is optimized for general-purpose CPUs. RandomX uses random code execution together with several memory-hard techniques to minimize the efficiency advantage of specialized hardware. We only found minor inconsistencies and formulated a few recommendations. These recommendations are mainly relevant when using alternative configurations but they are of less importance with the current configuration and usage of RandomX. The full report of the assessment can be found at the following address: [2]