"It's using part of the bitcoin address for a use which hasn't been thought of," he said.
The substitution in the bitcoin address means that whatever fraction of bitcoin is sent will be lost forever. That's because substitution removes the hash of the private key, which is needed to unlock and access the bitcoin, he said.
The service costs .005 BTC, which was about US$0.62 at Friday's market price. Most of the cost is consumed in transmitting the bitcoin and paying a small fee to the Bitcoin miners who contribute computing power to create the blockchain. Araoz said he takes about .002 BTC to fund running his servers.
Gavin Andresen, the lead developer for the Bitcoin Project, questioned in January whether using the Bitcoin blockchain and paying a fee would be any better than using free timestamp services.
"Blockchain timestamping seems to me like one of those gee-whiz ideas that appeals to us techies but isn't 'enough better' than existing solutions to be interesting to non-techies," he wrote on the Bitcoin forum.
Araoz acknowledges his system isn't perfect. Bitcoin transactions can take from a few minutes up to an hour, which doesn't provide a precise time when the document was necessarily created, just when a transaction was executed. And it doesn't prove ownership, either.
Still, it's an innovative application of Bitcoin's blockchain, and one that prompted dozens of positive and critical comments on the Bitcoin subreddit.
"I know this app doesn't solve this [problem] entirely, but it is a small step," Araoz said.
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