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 mad

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 for a company as large as Facebook and does not suggest a weakness in the .onion scheme. [1] https://github.com/lachesis/scallion https://github.com/lachesis/scallion [2] https://github.com/lachesis/scallion#speed--performance https://github.com/lachesis/scallion#speed--performance [3] https://www.amazon.com/dp/B0032F63TW https://www.amazon.com/dp/B0032F63TW [4] http://www.wolframalpha.com/input/?i=%282^%285*11-1%29+%2F+520*10^6%29+seconds http://www.wolframalpha.com/input/?i=%282^%285*11-1%29+%2F+5... [5] http://www.wolframalpha.com/input/?i=%24190+*+%282^%285*11-1%29+%2F+520*10^6%29+seconds+%2F+1+week http://www.wolframalpha.com/input/?i=%24190+*+%282^%285*11-1... [edit] Dustcore is very correct, correcting for my initial mistake, it would take 1.1 million years on a single GPU using scallion. Finding that sort of result in a month would require $2.6 billion worth of GPUs. Now I know facebook is known for spending billions on questionable purchases, but this would be a bit extreme even for them. How the hell have they managed this?