Since 2020 Tor Project had announced that the V2 version of the Onion addresses would be discontinued due to vulnerabilities present in the cryptography they used . Recently, the Tor development team recalled that in July 2021 the discontinuation of the previous version would begin, forcing all users to migrate to Onion V3.
The event reminder was made from the official Tor Project Twitter, where it was announced that, specifically, on July 15, 2021 Tor will release a new version that will disable support for Onion V2 addresses. Being the conclusive ending on October 15 of this year , at which time the stable version of Tor explorer will completely disable this version.
The difference between the 2 phases is that, in the one corresponding to July 15, 2021, it is proposed to discontinue the default compatibility with Onion V2, although users will still be able to use it by making some internal configurations in their browser. On the other hand, as of October 15, Tor will no longer be compatible, at all, with this old version .
The change is made After 3 years of being operational, the Onion V3 addresses launched on January 9, 2018, which, according to the development team itself, has better cryptography and more security than its predecessors . In the same way, the modification is made after the successful implementation of version V3 in all nodes of the Tor network, since V3 is currently the standard version.
The version change comes hand in hand with an improvement in the security and privacy of the users who use the services. Although, it should be noted that the discontinuation of version 2 does not directly affect users, but rather websites that do not update their addresses to the new version.
The reason for the change from Onion V2 to V3
The web addresses within the Tor browser have the name of the .onion domain, its counterparts being, for example, the . com . io . org or any other on the traditional web. These offer a type of encryption from the web to the user, creating untraceable encrypted connections.
Versions 2 of the .onion were developed shortly after Tor’s release in 2004 along with version 1 of the addresses.
The purpose it was to encrypt the connections using an algorithm for this purpose, which, in the case of the Onion V2, used the SHA-1. This encryption algorithm is one of the predecessors of the one used by Bitcoin (SHA256), which, at the time, offered a modest level of secure encryption for users.
With the exponential growth of computing in recent years, this algorithm became vulnerable, even, in practice, it was broken. This led to its discontinuation by various programs. The Chrome browser itself, showed a warning about those sites that used SSL certificates with SHA-1 encryption.
By 2015 the Tor development team set about creating a new level of security, given the vulnerability that was being created. By 2018 the product was ready, presenting version 3 of the Onion addresses , which improved its cryptographic signature algorithm using ed25519 that offers much better encryption than its predecessor.
Tor and Bitcoin
Tor is a secure network architecture, which is based on the distributed network paradigm, used by Bitcoin, where communication between nodes is carried out in a decentralized way. It encrypts and protects users’ connections from third-party traces.
Due to all this, Tor and Bitcoin are usually quite linked. Not only in dark themes, since T or is the browser used to enter the Deep Web , but in matters that provide benefit to the community.
One of these examples has been the winning project of the Hackthon of the MIT Expo Bitcoin 2021, reported by CriptoNoticias at the time, which was called Onion’78. Its objective was to improve privacy in Bitcoin transactions using the PayJoin system together with the Tor network architecture , thus allowing the use of more private connections. This being, just one of the many examples of Bitcoin projects that make use of Tor to increase privacy.