How do you encrypt a file such that it can be decrypted after a date, but not before? Use serial computations for proof-of-work using successive squaring, chained hashes, or witness encryption on blockchains. In cryptography, it is easy to adjust encryption of data so that one, some, or all people can decrypt it, or some combination thereof. Gpu bitcoin mining cluster survey techniques for time-lock crypto.
Proposals often resort to trusted-third-parties, which are vulnerabilities. Wikileaks made some headlines in 2010 when they released an insurance file, an 1. Of course, this is an all-or-nothing strategy. Wikileaks has no guarantees that the file will not be released prematurely, nor guarantees that it will eventually be released. Any one of those Wikileaks supporters could become disaffected and leak the key at any time – or if there’s only 1 supporter, they might lose the key to a glitch or become disaffected in the opposite direction and refuse to transmit the key to anyone.
Hope Wikileaks kept backups of the key! Now, it’s hard to imagine how some abstract math could observe an assassination and decrypt embarrassing files. Perhaps a different question could be answered – can you design an encryption scheme which requires no trusted parties but can only be broken after a certain date? In addition to the basic use of sending messages to the future, there are many other potential uses of timed-release crypto.
Our main contribution is an offline submission protocol which enables an author being currently offline to commit to his document before the deadline by continuously solving an RSA puzzle based on that document. When regaining Internet connectivity, he submits his document along with the puzzle solution which is a proof for the timely completion of the document. Dread Pirate Roberts of Silk Road 1 was arrested in October 2013 and his computer with his Bitcoin hoard seized, I thought of another use: conditional transfers of wealth. Ulbricht could create a time-locked copy of his bitcoins and give it to a friend. Here is one possible use case: imagine an offline digital cash system, so i. Otherwise the seller solves the puzzle and makes the deposit.
This use generalizes beyond darknet markets to all services or entities holding Bitcoins: the service can provide users with a time-locked version of the private keys, and regularly move its funds – if the service ever goes down, the users can retrieve their funds. One not-so-cute use is in defeating antivirus software. No trusted third-parties Note that this bars a lot of the usual suggestions for cryptography schemes. One approach is to focus on creating problems which can be solved with a large but precise amount of work, reasoning that if the problem can’t be solved in less than a month, then you can use that as a way to guarantee the file can’t be decrypted within a month’s time. This would be a proof-of-work system.