Quote from: kkurtmann on November 18, 2014, 07:02:36 AM

Quote from: cor on November 17, 2014, 10:22:34 PM

If you happen to be a fellow Slush Pool miner, there's a unique discount waiting for you. Kiss

http://satoshilabs.com/wp-content/uploads/2014/11/SlushPool_Trezor.png

Now you tell me! After I already bought 3 for full price. Been on Slush pool over 3 years

you and me, we both ...

Quote from: molecular on November 17, 2014, 08:01:31 PM

Quote from: binford on November 16, 2014, 08:26:50 PM

Quote from: blossbloss on November 16, 2014, 03:39:17 PM

Quote from: molecular on November 16, 2014, 08:15:30 AM

To prove your pdf existed, I would go a similar route as you took: I would hash the doc, convert the private key to an address and verify that the address has received money in the past. ...
Please note: you should move the money from that address. Anyone with the document can access it.

Excellent! Thanks.

you should not move all money from that address as the bitcoin paper describes pruning of transactions from blockchain for empty addresses. if you need your proof to be preserved longterm this is a risk to be aware of

This is a valid concern and I've thought about that: I think it's save to remove the money. There will most likely always be a complete transaction history available and it's good practice to keep the unspent transaction output set as clean (small) as possible because it has to be accessed quickly by servers/wallets.

Also: you'll have to keep the document itself anyways. So why not keep the block with the relevant tx in it along with it?

EDIT: another minor point: If you're concerned of losing the ability to prove existence due to the money being removed from the address, you would also have to keep your document secret to avoid someone else removing the money.

EDIT2: sorry for all the offtopic babble.

+1 apology for being off (trezor) topic here
I appreciate your thoughts and nod, nod and agree. you solved the pruning risk elegantly (keeping a copy of the block which contains my proof of existence tx), argument about keeping the document so why not bundle it with support data, it all makes perfect sense and I will adopt it in my argumentation as viable options of doing things.

as for keeping the document secret, that is ok 'cause my use case is about testaments and using rather higher fee but satoshi tokens for the stamping. now it can be reversed, using old coins, zero fees and spending them afterwards as usual.

how trezor fits here nicely is to sign message that describes the signing/timestamping with an address that would be used to actually timestamp a document. so that it all can be verfied in one eintopf of documents and signatures that are loosely related but can reveal much more info if the right off-blockchain data is added to it and is examined.

sorry for my rambling. i'm just very excited atm, been working on and off on probative value of electronic documents for a couple of years now and you just stimulated an are of my brain in an unexpected way