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I would like to be able to prove that a certain set of files was available through IPFS at a certain date.

How can I achieve that without resorting to centralized solutions or third party authorities?

Thanks!

swiftBoy
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Marco Barulli
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  • ipfs is integrating git like system for caching into their system. Not sure if its already done, but if it is, then be rest assured, it will be time stamped. I can check up over the weekend. – Varun Agarwal Jul 08 '16 at 15:45
  • Thanks @varun-agarwal! Any practical inputs on how to achieve the above goal would be very much appreciated. Cheers. – Marco Barulli Jul 14 '16 at 20:32

3 Answers3

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You could use a solution like opentimestamps to create a timestamp of your document using the Bitcoin network.

simbro
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You can create an Ethereum smart contract which takes in an IPFS hash and ties it with the current block timestamp.

Anyone will then be able to look up an IPFS hash and see if it's in the smart contract and the timestamp, as well the public address who submitted the transaction.

If you don't want to use Ethereum you can use any reliable blockchain such as Bitcoin.

Miguel Mota
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You can use the current block timestamp block.timestamp store this value then compare it to the current time when adding a folder.

Note: The block time can be manipulated by the miners see the following links. If the stakes are very high and there is incentive for people to cheat the contract then i suggest exploring other methods otherwise it doesn't seem too risky.

Can a contract safely rely on block.timestamp? - https://ethereum.stackexchange.com/questions/413/can-a-contract-safely-rely-on-block-timestamp

Need help understanding block.timestamp and how time works in the blockchain - https://forum.ethereum.org/discussion/14634/need-help-understanding-block-timestamp-and-how-time-works-in-the-blockchain

0xCourtney
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