An authentication method using Libra's Public Key and Secret Key. Use a signature by EdDSA. In the figure below, User “ALICE” pays the ticket fee to Ticket Center “BOB” with Libra and is authenticated with the signature ticket.

It is authentication based on the Libra client-key. But the communication between Bob and Alice doesn't put a load on the Libra blockchain. And the processing speed is fast.

Make this. Client and server authentication work sample for ticket application using the libra-auth method.

const EdDSA = require('elliptic').eddsa; const ec = new EdDSA('ed25519'); const { SHA3 } = require('sha3');

test()

function test(){

    //==============================================
    // Prepare Keys
    // Corresponds to 3 and 4 after 1 and 2
    // Communication with testnet is omitted this sourse
    // 
    
            //----------------------------------------------
            // ALICE

            // Alice's Private Key
            const AlicePriKeyHex='fa127e73935678a647daf3d3af2a934dc0e9c9c39dc4ac2e69c9c3648447ff53';
            // Create key pair from secret
            const AlicePriKey = ec.keyFromSecret(AlicePriKeyHex, 'hex');// hex string, array or Buffer

            // Import public key
            const AlicePubKeyHex = '78cd96278f49a78664faf50e9b238f3f5642360d80b3b0ce82782a4a8af3a8e9';
            const AlicePubKey = ec.keyFromPublic(AlicePubKeyHex, 'hex');

            //----------------------------------------------
            // BOB

            const BobPriKeyHex='16253458330e54b08e3d492d200776d8af2d0367bbca4ca59df88985175a6069';
            // Create key pair from secret
            const BobPriKey = ec.keyFromSecret(BobPriKeyHex, 'hex');// hex string, array or Buffer

            // Import public key
            const BobPubKeyHex = '6e6579f1f368f9a4ac6d20a11a7741ed44d1409a923fa9b213e0160d90aa0ecc';
            const BobPubKey = ec.keyFromPublic(BobPubKeyHex, 'hex');
    



    // Start testing from the 5th

    //==============================================
    // 5. BOB: Make the "sigB" by the msg hash and  Bob's Private Key.
    //        
    //         msg = sha3Hash('hello') // mk massage hash 
    //         sigB = BobPriKey.sign(msg) // Sign with BOB's private key.
    //         // on this test, without this wss send. 
    //         // wss.send(sigB, msg) 

            //----------------------------------------------
            // Massage
            const msg = (new SHA3(512)).update('msg hello').digest('hex');

            //----------------------------------------------
            // Sign
            const sigB = BobPriKey.sign(msg).toHex();

            //----------------------------------------------
            // Send "sigB" and msg to Alice by WebSocket
            // Omitted

    //==============================================
    // 6. ALICE: Verify by Bob's Public Key the signB and the msg that were received.
    //      
            const res6 = BobPubKey.verify(msg, sigB);
    
    //==============================================
    // 7. ALICE: if 6th is true then Make the "sigA" by the Alice's Private Key and the "sigB".
    //
    
            //----------------------------------------------
            // test for res6

            if(res6===true){
                    console.info('8. ALICE: OK. verify(msg, sigB) is true.');
            } else {
                    console.error('8. ALICE: Error. verify(msg, sigB) is false.');
            }
            
            //----------------------------------------------
            // if res6 is true then  Make the "sigA"
            
            let sigA; 
            if(res6){
                    sigA = AlicePriKey.sign(sigB)
            } else {
                    //goto 1
            }

    //==============================================
    // 8. BOB: Verify the "sigB" and "sigA" by Alice's Public Key.

            const res8 = AlicePubKey.verify(sigB, sigA);

    //==============================================
    // 9. BOB: if 8th is true then Alice login is OK.

            //----------------------------------------------
            // test for res8

            if(res8===true){
                    console.info('9. BOB: OK. verify(sigB, sigA) is true.');
            } else {
                    console.error('9.BOB: Error. verify(sigB, sigA) is false.');
            }
    

}

/* response */ 7. ALICE: OK. verify(msg, sigB) is true. 9. BOB: OK. verify(sigB, sigA) is true.