25. On Timestamping Documents
25
On TimestampingDocuments
HERE, Hal mentions that some people suggested using the block chain to timestamp documents by way of an extra hash. (See the earlier explanation of cryptographic hash in the section entitled Cryptographic hash function—a digital “fingerprint” in Chapter 2.)
[bitcoin-list] Bitcoin v0.1.5 released
Satoshi Nakamoto 2009-03-04 16:29:12
Hal Finney wrote:
That sounds good. I’d also like to be able to run multiple coin/block generators on multiple machines, all behind a single NAT address. I haven’t tried this yet so I don’t know if it works on the current software.
The current version will work fine. They’ll each connect over the Internet, while incoming connections only come to the host that port 8333 is routed to.
As an optimisation, I’ll make a switch “-connect=1.2.3.4” to make it only connect to a specific address. You could make your extra nodes connect to your primary, and only the primary connects over the Internet. It doesn’t really matter for now, since the network would have to get huge before the bandwidth is anything more than trivial.
BTW I don’t remember if we talked about this, but the other day some people were mentioning secure timestamping. You want to be able to prove that a certain document existed ata certain time in the past. Seems to me that bitcoin’s stack of blocks would be perfect for this.
Indeed, Bitcoin is a distributed secure timestamp server for transactions. A few lines of code could create a transaction with an extra hash in it of anything that needs to be timestamped. I should add a command to timestamp a file that way.
Later I want to add interfaces to make it really easy to integrate into websites from any server side language.
Right, and I’d like to see more of a library interface that could be called from programming or scripting languages, on the client side as well.
Exactly.
Satoshi Nakamoto
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