Proof of Existence Module
The Proof of Existence module in Mchain is a blockchain-based mechanism for registering and verifying the existence of any data or document. This module relies on SHA-256, a cryptographic hash function, to store unique hashes representing the data or documents. It's important to note that the module does not hold the actual file or data in the blockchain, but only the hash. This ensures privacy and efficiency, as the hash serves as a digital fingerprint of the data.
Generating SHA-256 Hash
To create a proof, you first need to generate a SHA-256 hash of your data or document. In Ubuntu, you can use the sha256sum command to do this. For example:
sha256sum filename.ext
This command will output the SHA-256 hash of the specified file.
CLI Commands
Create Proof
Allows users to create a new proof for a given hash.
mchaind tx proofofexistence create-proof [hash] --from [key-name] --chain-id [chain-id] --fees [fee]
Replace [hash] with the SHA-256 hash generated from your data or document.
Example:
$ mchaind tx proofofexistence create-proof a8e6b925fb040fb25b719516b5f5b1efa10850e7f61c1baf58964d8ee925e0d2 --from=mykey --chain-id=mchain-testnet-1 --fees=50umark
This command will:
- Create a proof.
- Execute the transaction from the account linked to
mykey.
Query Proof by Hash
Retrieves a specific proof using its hash.
mchaind q proofofexistence proof [hash]
Query Total Proofs
Returns the total number of proofs registered in the system.
mchaind q proofofexistence total-proofs
Query List of Proofs
Lists all proofs registered in the system.
mchaind q proofofexistence list-proofs
Query Module Parameters
Displays the current parameters of the Proof of Existence module.
mchaind q proofofexistence params
Parameters
The following table summarizes the configurable parameters for the Proof of Existence module:
| Parameter | Description | Type |
|---|---|---|
issue_fee | Fee charged for issuing a proof. | Coin |