I am trying to implement POE model based on Ethereum blockchain. Basically, I get sha-256 hash from a document, then I send a 0 ether transaction to myself and add document's hash to the "Data" field. Transaction gets validated and I can see it: https://ropsten.etherscan.io/tx/0x1f4d3136b16de5ca56e04edfbb5139e902d624a200846374f7cba8b598f6dd82 (currently I am doing it on testnet)
However, my input data was 15e2b0d3c3..... and in receipt data is 0x53369b7315e2b0...... Everything is okay, except that I don't understand why these 8 digits were inserted, what they stand for? And what's the purpose of this 0x in front of everything?
If someone could explain this in simple terms, I would be really grateful.