scallion

Nitpick about the website, but please don't use PGP short fingerprints like 0x46EBCD72F08E6717. They can be brute forced [0] very fast to get a different private key with the same fingerprint. You can also use them to generate keys with vanity fingerprints, which is pretty funny [1]. [0] https://github.com/lachesis/scallion [1] I have 0xDE4444AAAAAAAAAA, took me 5 minutes of bruteforcing on a laptop.

There are tools to do that automatically. A prefix of "xxx" or "xxxxxx" can be found almost instantaneously; "xxxxxxxxx" should be doable given an hour or two. https://github.com/lachesis/scallion

Facebook's hidden service address is particularly impressive: https://facebookcorewwwi.onion/ It seems like everything except the 'i' is a prefix, a lot of computing must have went in to generating it. One tool to do it is called 'Shallot' https://github.com/katmagic/Shallot The readme includes a table of estimated computing time required. A 15 char prefix like Facebook's is not even on the table, and a 14 char prefix is estimated to take 2.6 million years. There is also a GPU version which should be an order of magnitude faster: https://github.com/lachesis/scallion/blob/gpg/README.md Also, technically. the onion addresses not public keys, but derived from a public key. It's actually a hash of the public key. It appears that the hashing algorithm used is SHA1. Source: The last few lines of the easygen function https://github.com/katmagic/

For those wondering how to generate vanity Tor onion addresses in a more efficient manner (taking advantage of your GPU): https://github.com/lachesis/scallion

Scallion (https://github.com/lachesis/scallion) works really good for this. It uses OpenCL to leverage your GPU's to make cracking really fast.

There is a program called scallion [1] which can generate Vanity addresses like these. I am assuming that they searched for facebookwww?.onion and then just made up the acronym for the last character. They are therefore trying to brute force the first 11 characters of the address. The author of scallion estimates one can achieve 520 MH/s with a AMD Radeon HD5770 GPU [2] which retails for $190 [3], they then give the formula for calculating the time (in seconds) to have a 50% chance of finding a matching URL: 2^(5length-1) / hashspeed Which with a length of 11 and a hashspeed of 520M, would take about a year with the one GPU [4]. The total cost of the hardware to have a 50% chance of finding the vanity address "facebookwww?.onion" within a week would therefore be around $11 000 [5]. Imho, this is well within the realms of possibility f

I'm guessing they used something like scallion [0] or Shallot [1]. Bench marking Shallot on an Intel 3350P@3.10GHz: time ./shallot ^a -> 0.09 sec user time ./shallot ^aa -> 0.12 sec user time ./shallot ^aaa -> 0.12 sec user time ./shallot ^aaaa -> 0.47 sec user time ./shallot ^aaaaa -> 5.92 sec user time ./shallot ^aaaaaa -> 118 sec user Unfortunately OpenCL doesn't work with the nouveau drivers so I can't test scallion. Who knows how much they spent trying to brute force that onion address. EDIT: Ok looks like they went the backronym route [0] https://github.com/lachesis/scallion [1] https://github.com/katmagic/Shallot

There are a few different programs that will do it, but it comes down to brute force, so the difficulty depends on the length. https://github.com/katmagic/Shallot https://github.com/lachesis/scallion