DIY Blockchain Timestamping

Timestamping / notarization is a lot easier than you may think. The basic principle is to submit a file’s hash (checksum) on the bitcoin blockchain. This proves the file existed on the time it was submitted.

On you can get an html-file which does just that (note it is MD5, not the more secure SHA256).

There are two issues with this approach. 1) Manual timestamping is cumbersome. 2) Three cents in tx fees per timestamp; it quickly gets expensive.

To deal with the costs, you can gather multiple hashes in one file and finally timestamp this file. To prove the timestamp you need a copy of your original file, as well as the file with multiple hashes (because your hash is in this multi-hash-file),

A standard web server with MySql and PHP is all you need. Any programmer can set it up. Feel free to use the tools from Check out the github link for source code.