I would like to upload a file to my UI and then produce a hash of it so I could later store it on Ethereum. Here is the code I am using to upload the file:

   <label for="file input">Submit your file here</label>
   <input type="file"">

How can I create a hash of any file on the UI side so I can later submit this hash onto Ethereum?

closed as off-topic by Nicolas Massart, Achala Dissanayake, Ismael, shane, flygoing Jun 27 at 14:33

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question does not appear to be about Ethereum, the decentralized application platform and smart contract enabled blockchain, within the scope defined in the help center." – Nicolas Massart, Ismael, shane, flygoing
If this question can be reworded to fit the rules in the help center, please edit the question.

  • Please take your time to get acquainted with some implementation of web3 (web3.js probably most suitable in this case). – goodvibration Jun 21 at 13:53

First you need to write and deploy a simple storage smart-contract (with solidity and truffle), then you need to use the web3js library to connect to the blockchain and later to call your function in the smart-contract --> send a transaction to upload the hash of the file in your deployed smart contract

The web3 library provide a function to calcuate the hash of a given string so you should read your file as string or convert it somehow to string and call web3.utils.keccak256(string) to get the hash

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