cashu-workshop/index.html at main · supertestnet/cashu-workshop · GitHub

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<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <script src="https://supertestnet.github.io/blind-sig-js/blindSigJS.js"></script>
    <script src="https://cdn.jsdelivr.net/gh/6502/sha256@main/sha256.js"></script>
    <script>var SHA256 = string_or_uint8array => bytesToHex( sha256( string_or_uint8array ) );</script>
   	<script src="https://bundle.run/noble-secp256k1@1.2.14"></script>
   	<script>
   	    var isValidHex = hex => {
   	        if ( !hex ) return;
   	        var length = hex.length;
   	        if ( length % 2 ) return;
   	        try {
   	            var bigint = BigInt( "0x" + hex, "hex" );
   	        } catch( e ) {
   	            return;
   	        }
   	        var prepad = bigint.toString( 16 );
   	        var i; for ( i=0; i<length; i++ ) prepad = "0" + prepad;
   	        var padding = prepad.slice( -Math.abs( length ) );
   	        return ( padding === hex );
   	    }
   	</script>
   	<script>
   	    var hexToBytes = hex => Uint8Array.from( hex.match( /.{1,2}/g ).map( byte => parseInt( byte, 16 ) ) );

   	    var bytesToHex = bytes => bytes.reduce( ( str, byte ) => str + byte.toString( 16 ).padStart( 2, "0" ), "" );

   	    var hexToText = hex => {
   	        var bytes = new Uint8Array(Math.ceil(hex.length / 2));
   	        for (var i = 0; i < hex.length; i++) bytes[i] = parseInt(hex.substr(i * 2, 2), 16);
   	        var text = new TextDecoder().decode( bytes );
   	        return text;
   	    }
   	</script>
   	<script>
   	    var waitASec=num=>new Promise(res=>setTimeout(res,num*1000));
   	</script>
   	<script>
   	    var decomposeAmount = amount_to_decompose => {
   	        var decomposed = [];
   	        var getBaseLog = ( x, y ) => Math.log(y) / Math.log(x);
   	        var inner_fn = amt => {
   	            var exponent = Math.floor( getBaseLog( 2, amt ) );
   	            decomposed.push( 2 ** exponent );
   	            amount_to_decompose = amt - 2 ** exponent;
   	            if ( amount_to_decompose ) inner_fn(amount_to_decompose);
   	        }
   	        inner_fn( amount_to_decompose );
   	        return decomposed;
   	    }
   	</script>
</head>
<body>
	<center><h2 class="balance">0</h2></center></h1>
	<center>
        <button class="send">Send</button>
        <button class="receive">Receive</button>
    </center>
	<script>
		var utxos = [];
		var $ = document.querySelector.bind( document );
		var $$ = document.querySelectorAll.bind( document );
	    (async () => {
	        // Step 1 Create a 32 byte secret
	        var secret_for_msg = bytesToHex(blindSigJS.getRand(32));
	        console.log( "secret_for_msg:", secret_for_msg );
	        // Step 2 Pick one of the mint's keysets
	        var endpoint = `https://testnut.cashu.space`;
	        sessionStorage[ "endpoint" ] = endpoint;
	        var keysets = await fetch( `${endpoint}/v1/keysets` );
	        keysets = await keysets.json();
	        keysets = keysets[ "keysets" ];
	        console.log( "keysets:", keysets );
	        var keyset;
	        keysets.every( item => {if ( isValidHex( item.id ) && item.active ) {keyset = item.id;return;} return true;});
	        console.log( "keyset:", keyset );
	        // Step 3 Pick an amount and get its pubkey
	        var pubkeys = await fetch(`${endpoint}/v1/keys/${keyset}`);
	        pubkeys = await pubkeys.json();
	        pubkeys = pubkeys[ "keysets" ][ 0 ][ "keys" ];
	        console.log( "pubkeys:", pubkeys );
	        var amount_i_want = 256;
	        var amt_pubkey = pubkeys[ amount_i_want ];
	        console.log( "amt_pubkey:", amt_pubkey );
	        // Step 4 Get an LN invoice for that amount
	        var post_data = {
	            method: "POST",
	            headers: {"Content-Type": "application/json"},
	            body: JSON.stringify({"amount": amount_i_want, "unit": "sat"}),
	        }
	        var invoice_data = await fetch( `${endpoint}/v1/mint/quote/bolt11`, post_data );
	        invoice_data = await invoice_data.json();
	        console.log( "invoice_data:", invoice_data );
	        // Step 5 Pay that invoice (but not on testnut)
	        console.log( `pay this: ${invoice_data[ "request" ]}` );
	        var isPaid = async invoice => {
	            await waitASec( 5 );
	            var is_paid_info = await fetch( `${endpoint}/v1/mint/quote/bolt11/${invoice_data[ "quote" ]}` );
	            is_paid_info = await is_paid_info.json();
	            var is_paid = is_paid_info[ "paid" ];
	            console.log( "it is paid, right?", is_paid );
	            return is_paid || isPaid( invoice );
	        }
	        await isPaid( invoice_data[ "request" ] );
	        // Step 6 Prepare a sig request
	        var message = new blindSigJS.bsjMsg();
	        var B_ = await message.createBlindedMessageFromString( secret_for_msg );
	        var B_hex = blindSigJS.ecPointToHex( B_ );
	        var sig_request = {"quote": invoice_data[ "quote" ], "outputs": [{
	            "amount": amount_i_want,
	            "id": keyset,
	            "B_": B_hex,
	        }]}
	        console.log( "sig_request:", sig_request );
	        // Step 7 Get a blinded sig
	        var post_data = {
	            method: "POST",
	            headers: {"Content-Type": "application/json"},
	            body: JSON.stringify(sig_request),
	        }
	        var blinded_sigs = await fetch( `${endpoint}/v1/mint/bolt11`, post_data );
	        blinded_sigs = await blinded_sigs.json();
	        var blinded_sig = blinded_sigs[ "signatures" ][ 0 ][ "C_" ];
	        console.log( "blinded_sig:", blinded_sig );
	        // Step 8 Unblind the sig and create a "utxo"
	        var C_ = nobleSecp256k1.Point.fromCompressedHex( hexToBytes( blinded_sig ) );
	        amt_pubkey = nobleSecp256k1.Point.fromCompressedHex( hexToBytes( amt_pubkey ) );
	        var {C} = message.unblindSignature(C_, amt_pubkey);
	        var compressed_C = nobleSecp256k1.Point.fromHex( blindSigJS.ecPointToHex( C ) ).toHex( true );
	        var utxo = {
	            id: keyset,
	            amount: amount_i_want,
	            secret: secret_for_msg,
	            C: compressed_C,
	        }
	        console.log( "utxo:", utxo );
	        utxos.push( utxo );
	        var bal = 0;
	        utxos.forEach( item => bal = bal + item[ "amount" ] );
	        $( '.balance' ).innerText = bal;
	    })();
	    $( '.send' ).onclick = async () => {
	        var nut = {
	            mint: `https://testnut.cashu.space`,
	            proofs: [],
	        }
	        utxos.forEach( item => nut[ "proofs" ].push( item ) );
	        nut = "cashuA" + btoa( JSON.stringify( {token: [nut]} ) );
	        console.log( nut );
	        utxos = [];
	        $( '.balance' ).innerText = 0;
	    }
	    $( '.receive' ).onclick = async () => {
	        var token = prompt( `Enter a cashu token` );
	        token = token.substring( token.indexOf( "cashuA" ) + 6 );
	        token = JSON.parse( atob( token ) );
	        token.token[0]["proofs"].forEach(item => utxos.push(item));
	        var bal = 0;
	        utxos.forEach( item => bal = bal + item[ "amount" ] );
	        var secret_for_msg = bytesToHex( blindSigJS.getRand( 32 ) );
	        var message = new blindSigJS.bsjMsg();
	        var B_ = await message.createBlindedMessageFromString( secret_for_msg );
	        var B_hex = blindSigJS.ecPointToHex( B_ );
	        var new_utxo = {
	            "amount": utxos[ utxos.length - 1 ][ "amount" ],
	            "id": utxos[ utxos.length - 1 ][ "id" ],
	            "B_": B_hex,
	        }
	        var swap_data = {
	            "inputs": [ utxos[ utxos.length - 1 ] ],
	            "outputs": [ new_utxo ],
	        }
	        var post_data = {
	            method: "POST",
	            headers: {"Content-Type": "application/json"},
	            body: JSON.stringify( swap_data ),
	        }
	        var endpoint = sessionStorage[ "endpoint" ];
	        var blinded_sigs = await fetch( `${endpoint}/v1/swap`, post_data );
	        blinded_sigs = await blinded_sigs.json();
	        var blinded_sig = blinded_sigs[ "signatures" ][ 0 ][ "C_" ];
	        console.log( "blinded_sig:", blinded_sig );
		    var keyset = utxos[ utxos.length - 1 ][ "id" ];
		    var pubkeys = await fetch(`${endpoint}/v1/keys/${keyset}`);
		    pubkeys = await pubkeys.json();
		    pubkeys = pubkeys[ "keysets" ][ 0 ][ "keys" ];
		    var amount_i_want = utxos[ utxos.length - 1 ][ "amount" ];
		    var amt_pubkey = pubkeys[ amount_i_want ];
		    console.log( "amt_pubkey:", amt_pubkey );
		    amt_pubkey = nobleSecp256k1.Point.fromCompressedHex( hexToBytes( amt_pubkey ) );
            var new_C_ = nobleSecp256k1.Point.fromCompressedHex( hexToBytes( blinded_sig ) );
            var {C} = message.unblindSignature( new_C_, amt_pubkey );
            var compressed_C = nobleSecp256k1.Point.fromHex( blindSigJS.ecPointToHex( C ) ).toHex( true );
            var new_utxo = {
                id: utxos[ utxos.length - 1 ][ "id" ],
                amount: utxos[ utxos.length - 1 ][ "amount" ],
                secret: secret_for_msg,
                C: compressed_C,
            }
            utxos.splice( utxos[ utxos.length - 1 ][ "id" ], 1 );
            utxos.push( new_utxo );
            $( '.balance' ).innerText = bal;
        }
	</script>
</body>
</html>