What is V2 Onion Address?

What is V2 Onion Address?

A V2 Onion Address is a specialized type of domain that is exclusively utilized within the Tor network. This unique domain is distinguishable by its distinctive structure and format. The V2 Onion Address consists of a string of 16 characters. These characters can be any letter from the alphabet or decimal digits that fall within the range of 2 to 7. These 16 characters represent an 80-bit hash in base32.

A practical example of a V2 Onion Address is the v2 address of the Tor Project. The Tor Project is an organization that promotes and develops the Tor network. The specific V2 Onion Address for the Tor Project is http://expyuzz4wqqyqhjn.onion/. This address provides an example of the combination of 16 characters, including both letters from the alphabet and decimal digits, that form the unique domain exclusive to the Tor network. This specific address leads users directly to the Tor Project when accessed within the Tor network.

The V2 Onion Address is derived from an RSA 1024-bit private key. The process for creating a V2 Onion Address is as follows:

1. Create an RSA 1024-bit private key
2. Convert the private key to a public key using DER format
3. Remove the first 22 bytes
4. Calculate the SHA-1 checksum of this value
5. Take the first half of the checksum
6. Convert the checksum into a base32 80-bit hash

The V2 onion addresses, which were initially designed to enhance privacy and security, unfortunately have been found to possess inherent security vulnerabilities. This is largely attributed to the way in which these V2 onion addresses are created, which makes them susceptible to security breaches. The crux of the problem lies in the generation process of the V2 onion addresses. The methodology employed in this process allows different individuals, each owning a unique private key, to produce an identical V2 onion address. This is a phenomenon known as a preimage attack. Despite the fact that the odds of such an occurrence are astronomically low, the mere possibility of such a scenario inherently compromises the security of these addresses. As a result of these security concerns, the V2 onion addresses have been phased out. They were officially deprecated after September 2021, and replaced by V3 Onion Address. The V3 Onion Address has been designed to provide a more secure and reliable alternative to the V2 addresses. It employs a more updated or more secure signature algorithms and hashing methods in its generation process. By using the V3 Onion Address, you can ensure that your V3 onion address has better security against impersonation.