Basically to prove that something existed before a specific date. For instance, grab a random piece of paper on your desk with writings and then try and prove to me that the contents of that paper existed before last year, you can't really do it (easily). Before this, the only (easy) way to achieve this would be to send this document to a third party to store into a database that it did infact exist when sent to the database, but how can you prove that database wasn't manipulated? Another common way to prove something existed before a certain time would be to make a copy and send the copy through the mail to yourself. One you have received this copy from the mail, leave it unopened and now you have proof (through the mail service's date on the stamp) but this isn't too easy, some what of a hassle, and I think you could debate that you could fake it. (Faking the stamp, finding a way to get an opened document through the mail and than replacing the content later, etc.)
What this does is it stores a document's signature into the actual "history" of bitcoins which is public. ANYONE and EVERYONE can access this history of all transactions and by them storing the actual signature of the document into this public "log" you are now able to say that this document DID exist before the specific bitcoin transaction. This removes the hassle of all current methods of proving for existence and now no longer rely on a single third party (which could manipulate it themselves).
Your first paragraph isn't quite right. There have been cryptographic proof-of-timestamp systems for a long time, and they're described in standard crypto texts like Schneier's.
They work basically the same way, except that you have to set up your own network. When you want to timestamp something, you (just like this service) hash it together with the previous entry in the system, sign it, and publish that. The proof of the timestamp lies in how you had to look at the previous entry to make it, and the next, at yours. Compromising it would require a large number of participants to cooperate to re-write the history (and the participants' own records).
What this service does is avoid the need to integrate with an existing service or pay any of the record-keeping costs yourself, and it does so by piggy-backing off of bitcoin's distributed timestamp system, thereby making your timestamps at least as valid as bitcoin's, and increasing (significantly) the number of conspirators required to falsify it.
tl;dr: This is just like existing crypto timestamp systems except for the more extreme decentralization and using the bitcoin network's resources.
Comments
Basically to prove that something existed before a specific date. For instance, grab a random piece of paper on your desk with writings and then try and prove to me that the contents of that paper existed before last year, you can't really do it (easily). Before this, the only (easy) way to achieve this would be to send this document to a third party to store into a database that it did infact exist when sent to the database, but how can you prove that database wasn't manipulated? Another common way to prove something existed before a certain time would be to make a copy and send the copy through the mail to yourself. One you have received this copy from the mail, leave it unopened and now you have proof (through the mail service's date on the stamp) but this isn't too easy, some what of a hassle, and I think you could debate that you could fake it. (Faking the stamp, finding a way to get an opened document through the mail and than replacing the content later, etc.)
What this does is it stores a document's signature into the actual "history" of bitcoins which is public. ANYONE and EVERYONE can access this history of all transactions and by them storing the actual signature of the document into this public "log" you are now able to say that this document DID exist before the specific bitcoin transaction. This removes the hassle of all current methods of proving for existence and now no longer rely on a single third party (which could manipulate it themselves).
Your first paragraph isn't quite right. There have been cryptographic proof-of-timestamp systems for a long time, and they're described in standard crypto texts like Schneier's.
They work basically the same way, except that you have to set up your own network. When you want to timestamp something, you (just like this service) hash it together with the previous entry in the system, sign it, and publish that. The proof of the timestamp lies in how you had to look at the previous entry to make it, and the next, at yours. Compromising it would require a large number of participants to cooperate to re-write the history (and the participants' own records).
What this service does is avoid the need to integrate with an existing service or pay any of the record-keeping costs yourself, and it does so by piggy-backing off of bitcoin's distributed timestamp system, thereby making your timestamps at least as valid as bitcoin's, and increasing (significantly) the number of conspirators required to falsify it.
tl;dr: This is just like existing crypto timestamp systems except for the more extreme decentralization and using the bitcoin network's resources.