Hi Tomáš, if you loose the ots file you cannot prove the timestamp of the document.
There are multiple reason why the ots file is necessary: - What you find in the blockchain is not the hash of your file, it's an hash of multiple files timestamped together (with a merkle tree) - The public calendar cannot save the hash for every request, otherwise it would be too costly to mantain - You may want someone with the file cannot prove it's existance without the ots, thus the document is salted with random data 2018-04-05 9:48 GMT+02:00 Tomáš Karella <kare...@stemmark.cz>: > Dear Ots team, > > First of all, I impressed by your service and I really appreciate job you’ve > done. > > > > I would like to ask you, if it is possible to generate ots from a file. > Imagine the following situation, We have lost the ots file and found the > stamped file. Is there any option to generate hash from the file to verify > that it was stamped(that the hash is in the blockchain). > > > > Yours sincerely, > Tomáš Karella > -- Riccardo Casatta - @RCasatta <https://twitter.com/RCasatta>