Since mid-2022, the privacy-preserving Tor network has been plagued by denial-of-service attacks, making the network sluggish and sometimes downright impossible to use.
In its latest software release, Tor aims to “defend” against these attacks with proof of work, the same cryptographic mechanism that underpins and secures bitcoin. Using proof of work in some way to prevent attacks has been an idea in the Tor community for many years. Now it is finally in its place.
This roll out is aimed at preventing attackers from needing to use more computational resources to carry out their attacks.
Tor is a network that privatizes the IP addresses of the people who use it. It is also used by bitcoin and other cryptocurrency advocates to improve their privacy, for example by hiding the IP addresses of bitcoin nodes or where transactions are taking place.
Although both bitcoin and Tor now use the same proof-of-work technology, the implementation of the privacy network is quite different as its developers specifically designed it to protect against attacks on Tor.
“There are algorithmic similarities, but some important differences. Tor’s proof-of-work system is dynamic: instead of forcing clients to go behind a static target, we ask clients to use their proof-of-work effort. bid’,” explained Pawel Joneff, director of strategic communications for the Tor Project. decrypt,
“Onion Services” are websites or services that run on Tor, protecting the IP address of the website. The network’s algorithms are able to detect that a website is receiving a lot of traffic at once – let’s say from an attacker. When this happens, proof of work is triggered, requiring users to use more computational effort to visit the website.
Normal users should not notice this change, but attackers should, as they would have to use more computational power to have the same effect.
“We believe that the introduction of a proof-of-work mechanism will discourage attackers by making large-scale attacks costly and impractical, while prioritizing legitimate traffic,” Jonoff explained in a post announcing the release.
