81–86 of 86 posts
"Your document will not be uploaded. The cryptographic digest is calculated client-side." That's great, but I have to trust you there. For a document that really matters, I don't think I would. How about a box that allows me to specify my own SHA256 instead?
http://www.proofofexistence.com/developers"Your document will not be uploaded. The cryptographic digest is calculated client-side." That's great, but I have to trust you there. For a document that really matters, I don't think I would. How about a box that allows me to specify my own SHA256 instead?
There is a developer API that allows you to do this: http://www.proofofexistence.com/developers
Earlier quoted context omitted.
Collisions are a problem if you want to corrupt data, not if you specifically want a human validate it in a single document. E.g.: I claim that I authored the string "foo bar" with hash "1f2ec52b7743687..". Now you find a collision and go to court arguing: >> Your honor, but "3HSSHog*8FF9 z!!!!ady94765&$^#" also has the same hash! I think the court will still assume that "foo bar" is the correct original, not the gar…
That's not why it would be a problem. The problem is that I can author "foo bar" and "moo bar" constructed to hash the same, and then assert retroactively which one I meant. While collisions are likely to have random binary garbage in them, it may not matter - I am on phone now, but IIRC I have two PDFs on my desktop that have the same MD5, one of which viewed is an airbus pamphlet, the other being a Boeing one. (cre…
Earlier quoted context omitted.
That's not why it would be a problem. The problem is that I can author "foo bar" and "moo bar" constructed to hash the same, and then assert retroactively which one I meant. While collisions are likely to have random binary garbage in them, it may not matter - I am on phone now, but IIRC I have two PDFs on my desktop that have the same MD5, one of which viewed is an airbus pamphlet, the other being a Boeing one. (cre…
Can we see them?
http://th.informatik.uni-mannheim.de/people/lucks/HashCollis...
http://www.win.tue.nl/hashclash/ChosenPrefixCollisions/ has a multicollision: 12 PDF files with different content and the same MD5 hash.
"Your document will not be uploaded. The cryptographic digest is calculated client-side." That's great, but I have to trust you there. For a document that really matters, I don't think I would. How about a box that allows me to specify my own SHA256 instead?
Couple questions. 1) AFAIK, bitcoin has "comments" within transactions. Why not embed the checksum as a comment in a transaction between wallets you control? 2) In the approach described here, no coins are being sent with the transaction (right?). Are blockchain participants really accepting NOP transactions involving 0 BTC transfers. Maybe I missed something. 3) As others pointed out, requiring the whole file to be…
1) Comments are enabled as a service by blockchain.info. For details on how the Genesis Block (and comment by Satoshi) was formed, look at the Bitcoin Wiki[1] 2) Coins are being sent. The Developer page says you must send at least 0.00000001 BTC. Edit: actually 500000 Satoshi. 3) Agree. So does the service. See the Developer Page[2] [1] https://en.bitcoin.it/wiki/Genesis_block [2] http://www.proofofexistence.com/deve…