...
bitproof.io will hash just about any document and place it on the blockchain. They also store the original at their website. Here is an experiment that I recently did, making a document with a photo, some links and a small table of data from MS Excel. Total size of the document is +/- 530 KB. The doc can be found here:
https://docs.google.com/document/d/1M-vO0h0W_nLy-Z1Sz8xiYAhaCbmTMThL8FnW7hcoCkw/I hashed that with bitproof, they placed it (the hash) on the blockchain, and my document is also at their website, it can be opened by the account owner at bitproof (in this case me).
You also need to have the document stored on your (local) computer to hash it, at least for now.
Here is the transaction no. on the blockchain to see what bitproof.io did:
f33e63974710ea830cb8d5126afbac14b1f5dd3ee3a4dc33cb9e4fba59697aaa
If you view this with
blockchain.info, you can see the interesting looking coding (near the bottom of the page) for the "OP_RETURN" output mentioned above.
So, by hashing your document (can be large, makes no difference), and placing the
HASH on the blockchain (a similar service is offered by proofofexistence.com), and putting in one or more links to whatever it is you want preserved (at Google Docs, Dropbox, etc.).
* * *
Someone (IMO) is going to make a lot of money doing this...factom.org looks like the big player in this space as of now.
* * *
Re paying something, bitproof may (or may not) ask for a small fee, they are a new service. You could also pay (donation) to the Bitcoin Foundation (working on enhancing Bitcoin) or even a small donation to one or more miners (I am going to try and do all of this the next time I put up a doc on the blockchain), probably the key players most affected by
"blockchain bloat" feared by the purists...