Firmware Update for Trezor Model T (version 2.3.4) for Monero Hard Fork

by Anthony Allen

Today we released a new firmware update for the Trezor Model T, firmware version 2.3.4. This is a small functional upgrade adding the necessary firmware support to ensure a seamless transition when Monero undergoes a hard fork (HF13) later this month, on October 17th 2020.

This firmware update is not compulsory and is recommended only if you use Monero (XMR) with your Trezor. Visit your Trezor wallet to download the firmware now.

What is the Monero Hard Fork?

A hard fork is a way to upgrade blockchain software, according to shared consensus. On some networks, this sometimes results in coins being duplicated as the older blockchains continue to be maintained, known as a ‘contentious’ fork. Monero hard forks are non-contentious, meaning that their hard forks do not produce a ‘chain split’ event, and that no new coins will be produced as a result.

To prepare for the upgrade, Monero users will need to update to the newest Monero wallet version v0.17.0.1 (named Oxygen Orion), which is already available, and update their firmware. The network will then be upgraded on October 17th and you should be able to take advantage of the benefits below.

What will the update do?

This fork brings a change in the transaction signature algorithm being used. In technical terms, it replaces the current MLSAG (a multilayered linkable signature) with a similar algorithm known as CLSAG (concise linkable signature), a recently audited, simplified way to process and confirm transactions, promising greater efficiency and security when using the network.

We asked Dušan Klinec, who was pivotal to this firmware upgrade, to expand on the benefits:

1. Monero users could see up to 25% less data transferred per transaction, typically from 2.5kB to 1.9 kB, with an expectation that performance will be significantly improved as the blockchain will grow slower, synchronization will take less time/bandwidth and transaction fees will be a bit lower.
2. The signature verification algorithm is roughly 20% faster for CLSAG transactions and 10% for MLSAG transactions. Full Monero nodes synchronizing the whole blockchain will benefit from this.
3. The CLSAG scheme was formally proven under a stronger model than MLSAG was, where the modeled attacker is given stronger capabilities, so the security assurances are also stronger and more rigorous. The source code and the scheme was audited by an independent party. CLSAG is essentially a drop-in replacement for MLSAG, it has the same functional features, so the change is transparent to users.

Strength in Numbers

We are outspoken on the benefits of open collaboration, and once again we would like to acknowledge the continued efforts of Dušan Klinec, for all his Monero code contributions to Trezor. A hard fork reflects the work of many people, working together on a huge scale. We would also like to recognize the Monero team for their ongoing work to improve the privacy and security of their network. It takes significant time and effort to organize these upgrades and a privacy-focused project like Monero benefits immensely from the greater decentralization achieved by community-sourced contributions.