Long-story short, I'm building a social network, where each of my users has an onion address, and can sign their status updates with their private keys (so their friends can share them when they're offline). Hidden service V2 is very convenient for this:

The key hashes are short. The keys are in PEM format.

Is there a way to specify SHA512 hashing, with a 16-character URL length? 56 character URLs are inconvenient, and with all the focus TOR has placed on ease of use lately (ditching Vidalia so users had shorter wait times, and assured connection), one would think short URLs would be a consideration.

At the moment, I'm running on HiddenServiceVersion 2, but the software says support for that will soon be dropped. I need options.

1 Answer 1


As v2 services will be removed from the network later this year, v3 onion services are your only option. You cannot change the length of v3 addresses. They need to fit the entire ed25519 public key of the service and a checksum, and the Tor protocol does not allow you to deviate from this. Unlike v2 addresses, v3 addresses do not include a hash. See Chapter 6 "Encoding onion addresses [ONIONADDRESS]" of the v3 spec to see the only address format that Tor allows.

The onion address naming issue is difficult to solve, but Tor people are always looking for new ways to improve usability: https://blog.torproject.org/cooking-onions-names-your-onions

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