# Derived private identifiers

Simple deterministic unique ID generation based on a private key without leaking information and authorizing a public key based on a private nonce and the original private key. Making 'sure' that you can only authorize yourself.

pragma circom 2.0.2;
include "../node_modules/circomlib/circuits/poseidon.circom";

template PrivateAccountDerivation() {
    signal input website;
    signal input nonce;
    signal input privateKey;

    //Output that is always unique, but doesn't leak identity information.
    signal output uniqueID;
    //Public key used for further communication
    signal output authorizedPublicKey;
    
    component hashed = Poseidon(2);
    hashed.inputs[0] <== website;
    hashed.inputs[1] <== privateKey;
   
    component newKey = Poseidon(2);
    newKey.inputs[0] <== nonce;
    newKey.inputs[1] <== privateKey;

    authorizedPublicKey <== newKey.out * newKey.out; //Implement proper private key => pub key generation
    
    //TODO identity credential verification etc.

    uniqueID <== hashed.out;
   
}
component main{public [website]} = PrivateAccountDerivation();

Related article: https://ovanwijk.medium.com/derived-private-identifiers-42837192c036