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Bitcoin attests data existed as of Thu May 28 2015 UTC $ ./ots -v verify examples/ots Assuming target filename is 'examples/hello-world.txt' Hashing file, algorithm sha256 Got digest 03ba204e50d126e4674c005e04d82e84c21366780af1f43bd54a37816b6ab340 Attestation block hash: 000000000000000003e892881a8cdcdc117c06d444057c98b6f04a9ee75a2319 Attested time: 1432827678 Success!

Bitcoin attests data existed as of Thu May 28 2015 UTC .

Timestamps can’t help you here: Byte Coin’s creators wouldn’t have timestamped anything.

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To verify the proof, all that needs to be done is to replay the operations, and check that the final result is a message that you already know existed at a certain time.

Since every commitment operation is guaranteed to have a different result for a different input, there’s no way to change the message we’re timestamping without changing the result and invalidating the timestamp.

We can see the actual operations in our timestamp with: $ ./ots info examples/ots File sha256 hash: 03ba204e50d126e4674c005e04d82e84c21366780af1f43bd54a37816b6ab340 Timestamp: ripemd160 prepend 0100000001e482f9d32ecc3ba657b69d898010857b54457a90497982ff56f97c4ec58e6f98010000006b483045022100b253add1d1cf90844338a475a04ff13fc9e7bd242b07762dea07f5608b2de367022000b268ca9c3342b3769cdd062891317cdcef87aac310b6855e9d93898ebbe8ec0121020d8e4d107d2b339b0050efdd4b4a09245aa056048f125396374ea6a2ab0709c6ffffffff026533e605000000001976a9140bf057d40fbba6744862515f5b55a2310de5772f88aca0860100000000001976a914 append 88ac00000000 sha256 sha256 prepend a987f716c533913c314c78e35d35884cac943fa42cac49d2b2c69f4003f85f88 sha256 sha256 prepend dec55b3487e1e3f722a49b55a7783215862785f4a3acb392846019f71dc64a9d sha256 sha256 prepend b2ca18f485e080478e025dab3d464b416c0e1ecb6629c9aefce8c8214d042432 sha256 sha256 append 11b0e90661196ff4b0813c3eda141bab5e91604837bdf7a0c9df37db0e3a1198 sha256 sha256 append c34bc1a4a1093ffd148c016b1e664742914e939efabe4d3d356515914b26d9e2 sha256 sha256 append c3e6e7c38c69f6af24c2be34ebac48257ede61ec0a21b9535e4443277be30646 sha256 sha256 prepend 0798bf8606e00024e5d5d54bf0c960f629dfb9dad69157455b6f2652c0e8de81 sha256 sha256 append 3f9ada6d60baa244006bb0aad51448ad2fafb9d4b6487a0999cff26b91f0f536 sha256 sha256 prepend c703019e959a8dd3faef7489bb328ba485574758e7091f01464eb65872c975c8 sha256 sha256 append cbfefff513ff84b915e3fed6f9d799676630f8364ea2a6c7557fad94a5b5d788 sha256 sha256 prepend 0be23709859913babd4460bbddf8ed213e7c8773a4b1face30f8acfdf093b705 sha256 sha256 verify Bitcoin Block Header Attestation(358391) you create the timestamp: so long as you can extract a valid list of commitment operations that the Open Timestamps protocol supports, you can create a timestamp that any Open Timestamps-compatible verifier can verify.

Additionally, rather than being limited to a linear list of operations, timestamps are actually of operations, with the root of the tree being the message, the edges the commitment operations, and the leaves the attestations.

Thus we can say Bitcoin is a Of course, our message “Hello World! With another field, called the is calculated by taking all the transactions in a block and creating a merkle tree, shown here in this diagram from the book Mastering Bitcoin: Each arrow represents a cryptographic hash function, which takes an variable-length message, and transforms it to a fixed-length digest.

Importantly, a secure hash function has the property that it’s not possible to find two messages that hash to the same digest.Finally, Riccardo Casatta contributed to development and testing, and implemented an earlier version of Open Timestamps on his Eternity Wall service.A timestamp proves that a message existed prior to some point in time; timestamps are occasionally referred to as “proofs-of-existence”.Pairs of messages that “collide” to produce the same digest These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow.And they strongly imply that brute-force attacks against 256-bit keys will be infeasible until computers are built from something other than matter and occupy something other than space.You’ll need a local Bitcoin Core node (a pruned node is fine) with the $ cat examples/Hello World!

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