Reading the <a href="https://proofofexistence.com/about" rel="nofollow">https://proofofexistence.com/about</a> is really helpful, because I really didn't understand this at all.<p>While this is interesting, is there any concern about over use of the bitcoin blockchain? It's currently 65GB in size[0], which means it's fairly usable, and with a big enough system you could still store the entire thing in memory. What happens when it's 65TB? 65PB? Won't using it for lots and lots of things cause issues long term? Or am I missing something here?<p>[0] <a href="https://blockchain.info/charts/blocks-size?timespan=all" rel="nofollow">https://blockchain.info/charts/blocks-size?timespan=all</a>
It is good to compare with the legibility of a proof of existence Ethereum contract: <a href="https://github.com/maran/notareth/blob/master/contract.sol" rel="nofollow">https://github.com/maran/notareth/blob/master/contract.sol</a>
Similar is OriginStamp <a href="http://www.originstamp.org/" rel="nofollow">http://www.originstamp.org/</a> which is free; it does this by batching up a day of hashes into a single master hash which is then timestamped by Bitcoin.<p>I've written up some shell and Git scripts you can use to very easily timestamp stuff: <a href="http://www.gwern.net/Timestamping" rel="nofollow">http://www.gwern.net/Timestamping</a> Timestamping has come in handy for me in the past; you rarely need a cryptographically strong timestamp but when you do, it's important.
ryan-c beat me to it. Trusted time-stamping is probably better given there's reputable businesses that have existed for a long time and probably court precedents for their models. Their model is also <i>way</i> more efficient than Bitcoin as alternatives often are. Link here:<p><a href="https://en.wikipedia.org/wiki/Trusted_timestamping" rel="nofollow">https://en.wikipedia.org/wiki/Trusted_timestamping</a><p>Here's a few companies specializing in it with various tradeoffs:<p><a href="http://www.surety.com/digital-copyright-protection/prove-ownership.aspx" rel="nofollow">http://www.surety.com/digital-copyright-protection/prove-own...</a><p><a href="http://www.proofspace.com/timestamping/" rel="nofollow">http://www.proofspace.com/timestamping/</a><p><a href="https://www.digistamp.com/" rel="nofollow">https://www.digistamp.com/</a><p>Here's a paper on fast, decentralized security via witnesses that has timestamping at 120,000 requests a second with 4,000 witnesses:<p><a href="http://arxiv.org/pdf/1503.08768.pdf" rel="nofollow">http://arxiv.org/pdf/1503.08768.pdf</a>
I feel like I used this years ago...<p>Oh, I did. <a href="https://news.ycombinator.com/item?id=6809929" rel="nofollow">https://news.ycombinator.com/item?id=6809929</a>
I like this. Would have been amazing if this existed before the social explosion of the web. Where everyone is constantly stealing everyone elses work.
Let me see if I'm thinking on the right track about potential applications here.<p>First thing I thought of was proactive defense against someone patenting an idea by proving your prior art without necessarily divulging the information (or divulging it, while proving its chronologically prior existence).<p>After that, my mind jumped to media, such as the ability to be provably certain a given piece of media hasn't been altered after the fact (docs, images, contracts, video, audio, etc.), and that it provably existed when a party claims it did.<p>A bit on the nefarious side, I thought of being able to prove the existence of certain media a party wishes to use for blackmail or some other purpose.<p>Maybe applicable to the HN/YC crowd—especially given a certain case that recently made news here about a YC alum—a means of proving the existence of, say, founder agreements when establishing a company, so that protracted legal disputes over ownership could be aided and possibly shortened by irrefutable proof those agreements existed at a particular point in time.<p>Disclaimer: not a Bitcoin user, and know practically nothing substantial about it.
Was I really the first to upload a TXT file that only had the words "hello world"?<p><a href="https://proofofexistence.com/detail/b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9" rel="nofollow">https://proofofexistence.com/detail/b94d27b9934d3e08a52e52d7...</a><p>I was expecting to see someone else's document that had that text.
I've seen people post SHA-1s on Twitter for things (like proof of an iOS jailbreak) that they aren't ready to release yet. I suppose this is a more reliable method for that.
Bitcoin was originally described as a "peer-to-peer distributed timestamp server"[1] so this is an ideal use case.<p>1. <a href="https://bitcoin.org/bitcoin.pdf" rel="nofollow">https://bitcoin.org/bitcoin.pdf</a>