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Add support for sending to Lightning Addresses (LUD-16)
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@hsjoberg
hsjoberg committed Aug 20, 2021
1 parent 7a04403 commit 5b9f752
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Showing 5 changed files with 192 additions and 126 deletions.
93 changes: 55 additions & 38 deletions src/state/LNURL.ts
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Original file line number Diff line number Diff line change
@@ -1,3 +1,7 @@
//
// Sorry for the condition in this file.
// Reach out to me on Telegram @hsjoberg or lnurl mafia group https://t.me/lnurl if you have any questions.
//
import { Action, action, Thunk, thunk } from "easy-peasy";
import * as Bech32 from "bech32";
import { Hash as sha256Hash, HMAC as sha256HMAC } from "fast-sha256";
Expand All @@ -7,7 +11,6 @@ import { IStoreModel } from "./index";
import { IStoreInjections } from "./store";
import { timeout, bytesToString, getDomainFromURL, stringToUint8Array, hexToUint8Array, bytesToHexString } from "../utils/index";

import Long from "long";
import { lnrpc } from "../../proto/proto";
import { LndMobileEventEmitter } from "../utils/event-listener";

Expand All @@ -16,6 +19,8 @@ const log = logger("LNURL");

export type LNURLType = "channelRequest" | "login" | "withdrawRequest" | "payRequest" | "unknown" | "error" | "unsupported";

export type LightningAddress = string;

export interface ILNUrlChannelRequest {
uri: string;
callback: string;
Expand Down Expand Up @@ -129,6 +134,8 @@ export interface ILNUrlModel {
lnUrlObject: LNUrlRequest | undefined;

clear: Action<ILNUrlModel>;

resolveLightningAddress: Thunk<ILNUrlModel, LightningAddress>;
};

export const lnUrl: ILNUrlModel = {
Expand Down Expand Up @@ -260,42 +267,6 @@ export const lnUrl: ILNUrlModel = {
const signedMessage = secp256k1.ecdsaSign(hexToUint8Array(lnUrlObject.k1), linkingKeyPriv);
const signedMessageDER = secp256k1.signatureExport(signedMessage.signature)

/*
// FOLLOWS THE LNURL-AUTH SPECIFICATION
// https://github.com/btcontract/lnurl-rfc/blob/master/lnurl-auth.md
// Key derivation for Bitcoin wallets:
// 1. There exists a private hashingKey which is derived by user LN WALLET using m/138'/0 path.
const hashingKey = await injections.lndMobile.wallet.derivePrivateKey(138, 0);
// const hashingKeyPub = await injections.lndMobile.wallet.deriveKey(138, 0);
// 2. LN SERVICE domain name is extracted from login LNURL and then hashed using hmacSha256(hashingKey, service domain name).
const domain = getDomainFromURL(lnUrlStr);
const hmac = new sha256HMAC(hashingKey.rawKeyBytes);
const derivationMaterial = hmac.update(stringToUint8Array(domain)).digest();
// 3. First 16 bytes are taken from resulting hash and then turned into a sequence of 4 Long values which are in turn used
// to derive a service-specific linkingKey using m/138'/<long1>/<long2>/<long3>/<long4> path
// ?? walletrpc.DerviceKey does not allow deriving from such specific path
// LN WALLET may choose to use a different derivation scheme but doing so will make it unportable.
// That is, users won't be able to switch to a different wallet and keep using a service bound to existing linkingKey.
// We cannot derive the correct key in lnd so we are taking the 4 first bytes from the derivationMaterial
// and using that instead
const first4 = derivationMaterial.slice(0, 4);
const keyIndex = Long.fromBytesBE(first4 as unknown as number[], true).toNumber();
const linkingKey = await injections.lndMobile.wallet.derivePrivateKey(138, keyIndex);
log.d("key derived from family and index", [linkingKey.rawKeyBytes, 138, keyIndex]);
// Wallet to service interaction flow:
// 1, 2 omitted
// 3. Once accepted, user LN WALLET signs k1 on secp256k1 using linkingPrivKey and DER-encodes the signature.
const signedMessage = secp256k1.ecdsaSign(hexToUint8Array(lnUrlObject.k1), linkingKey.rawKeyBytes);
const signedMessageDER = secp256k1.signatureExport(signedMessage.signature);
const linkingKeyPub = secp256k1.publicKeyCreate(linkingKey.rawKeyBytes, true);
// const signedMessageDER = (await signMessage(138, keyIndex, hexToUint8Array(lnUrlObject.k1))).signature;
// const linkingKeyPub = (await deriveKey(138, keyIndex)).rawKeyBytes;
// log.d("signedMessageDER", [signedMessageDER]);
// log.d("linkingKeyPub", [linkingKeyPub]);
*/

// LN WALLET Then issues a GET to LN SERVICE using
// <LNURL_hostname_and_path>?<LNURL_existing_query_parameters>&sig=<hex(sign(k1.toByteArray, linkingPrivKey))>&key=<hex(linkingKey)>
const url = (
Expand All @@ -319,7 +290,7 @@ export const lnUrl: ILNUrlModel = {
if (response.status === "OK") {
return true;
}
throw new Error(response.reason!);
throw new Error(response.reason! ?? "Invalid response: " + JSON.stringify(response));
}
else {
throw new Error("Requirements not satisfied, type must be login and lnUrlObject must be set");
Expand Down Expand Up @@ -476,6 +447,52 @@ export const lnUrl: ILNUrlModel = {
state.lnUrlObject = undefined;
}),

resolveLightningAddress: thunk(async (actions, lightningAddress) => {
actions.clear();
// https://github.com/fiatjaf/lnurl-rfc/blob/luds/16.md
// The idea here is that a SERVICE can offer human-readable addresses for users or specific internal endpoints
// that use the format <username>@<domainname>, e.g. [email protected]. A user can then type these on a WALLET.
//
// Upon seeing such an address, WALLET makes a GET request to
// https://<domain>/.well-known/lnurlp/<username> endpoint if domain is clearnet or http://<domain>/.well-known/lnurlp/<name> if domain is onion.
// For example, if the address is [email protected], the request is to be made to https://bitcoin.org/.well-known/lnurlp/satoshi.
const [username, domain] = lightningAddress.toLowerCase().split("@");
if (domain == undefined) {
throw new Error("Invalid Lightning Address");
}

// Normal LNURL fetch request follows:
const lnurlPayUrl = `http://${domain}/.well-known/lnurlp/${username}`;
actions.setLNUrlStr(lnurlPayUrl);
const result = await fetch(lnurlPayUrl);

if (!result.ok) {
let error;
try {
error = await result.json();
} catch {
log.i("error", [result]);
throw new Error("Could not pay");
}
throw new Error(error.reason ?? "Could not pay");
}

const lnurlObject: LNUrlRequest | ILNUrlPayResponseError = await result.json();

if (isLNUrlPayResponseError(lnurlObject)) {
log.e("Got error")
throw new Error(lnurlObject.reason);
}

log.v(JSON.stringify(lnurlObject));
if (lnurlObject.tag === "payRequest") {
actions.setType("payRequest");
actions.setLNUrlObject(lnurlObject);
return true;
}
return false;
}),

lnUrlStr: undefined,
type: undefined,
lnUrlObject: undefined,
Expand Down
174 changes: 89 additions & 85 deletions src/windows/LNURL/PayRequest.tsx
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
import React, { useEffect, useState } from "react";
import { Vibration, StyleSheet, Linking, Alert } from "react-native";
import { Vibration, StyleSheet, Linking, Alert, KeyboardAvoidingView } from "react-native";
import Clipboard from "@react-native-community/clipboard"
import { Body, Card, Text, CardItem, H1, View, Button, Input, Spinner } from "native-base";
import { StackNavigationProp } from "@react-navigation/stack";
Expand Down Expand Up @@ -92,7 +92,7 @@ export default function LNURLPayRequest({ navigation, route }: IPayRequestProps)
}

const onChangeBitcoinInput = (newText: string) => {
const msat = unitToSatoshi(Number.parseFloat(newText), bitcoinUnit) * 1000;
const msat = unitToSatoshi(Number.parseFloat(newText.replace(/,/g, ".")), bitcoinUnit) * 1000;
setSendAmountMSat(msat);
};

Expand Down Expand Up @@ -276,93 +276,97 @@ export default function LNURLPayRequest({ navigation, route }: IPayRequestProps)
);
}


return (
<Blurmodal useModalComponent={false} goBackByClickingOutside={false}>
<Card style={style.card}>
<CardItem style={{ flexGrow: 1 }}>
<Body>
<View style={{ display: "flex", flexDirection: "row", justifyContent: "space-between", width: "100%" }}>
<H1 style={style.header}>
Pay
</H1>
{__DEV__ &&
<Button small={true} onPress={viewMetadata}>
<Text style={{ fontSize: 7.5 }}>View technical metadata</Text>
</Button>
}
</View>
<Text style={style.text}>
{domain} asks you to pay for a product.
</Text>
<Text style={style.text}>
Description:{"\n"}
{text}
</Text>
<Text style={{ marginBottom: 28 }}>
Price:{"\n"}
{minSpendableFormatted} ({minSpendableFiatFormatted})
{(minSpendable !== maxSpendable) &&
<Text> to {maxSpendableFormatted} ({maxSpendableFiatFormatted})</Text>
<KeyboardAvoidingView style={{ flex: 1 }} behavior="height">
<Blurmodal useModalComponent={false} goBackByClickingOutside={false}>
<Card style={style.card}>
<CardItem style={{ flexGrow: 1 }}>
<Body>
<View style={{ display: "flex", flexDirection: "row", justifyContent: "space-between", width: "100%" }}>
<H1 style={style.header}>
Pay
</H1>
{__DEV__ &&
<Button small={true} onPress={viewMetadata}>
<Text style={{ fontSize: 7.5 }}>View technical metadata</Text>
</Button>
}
</View>
<Text style={style.text}>
{domain} asks you to pay.
</Text>
<Text style={style.text}>
Description:{"\n"}
{text}
</Text>
<Text style={{ marginBottom: 28 }}>
Price:{"\n"}
{minSpendableFormatted} ({minSpendableFiatFormatted})
{(minSpendable !== maxSpendable) &&
<Text> to {maxSpendableFormatted} ({maxSpendableFiatFormatted})</Text>
}
</Text>
{typeof commentAllowed === "number" && commentAllowed > 0 &&
<>
<Text>
Comment to {domain} (max {commentAllowed} letters):
</Text>
<View style={{ flexDirection:"row" }}>
<Input onChangeText={setComment} keyboardType="default" style={[style.input, { marginTop: 9, marginBottom: 16 }]} />
</View>
</>
}
</Text>
{typeof commentAllowed === "number" && commentAllowed > 0 &&
<>
<Text>
Comment to {domain} (max {commentAllowed} letters):
</Text>
<View style={{ flexDirection:"row" }}>
<Input onChangeText={setComment} keyboardType="default" style={[style.input, { marginTop: 9, marginBottom: 16 }]} />
</View>
</>
}
{image &&
<ScaledImage
uri={"data:image/png;base64," + image}
height={190}
style={{
alignSelf: "center",
marginBottom: 28,
}}
/>
}
<View style={style.actionBar}>
<Button
disabled={doRequestLoading}
success
onPress={onPressPay}
style={{
marginLeft: 10,
width: 58,
}}
small={true}
>
{!doRequestLoading && <Text>Pay</Text>}
{doRequestLoading && <Spinner style={{ flex:1 }} size={26} color={blixtTheme.light} />}
</Button>
{minSpendable !== maxSpendable &&
<Input
onChangeText={onChangeBitcoinInput}
keyboardType="numeric"
returnKeyType="done"
placeholder={`${minSpendableFormatted} to ${maxSpendableFormatted}`}
style={style.input}
{image &&
<ScaledImage
uri={"data:image/png;base64," + image}
height={190}
style={{
alignSelf: "center",
marginBottom: 28,
}}
/>
}
<Button
onPress={cancel}
style={{
marginRight: 10,
}}
danger
small={true}
>
<Text>Cancel</Text>
</Button>
</View>
</Body>
</CardItem>
</Card>
</Blurmodal>
<View style={style.actionBar}>
<Button
disabled={doRequestLoading}
success
onPress={onPressPay}
style={{
marginLeft: 10,
width: 52

}}
small={true}
>
{!doRequestLoading && <Text>Pay</Text>}
{doRequestLoading && <Spinner style={{ flex:1 }} size={26} color={blixtTheme.light} />}
</Button>
{minSpendable !== maxSpendable &&
<Input
onChangeText={onChangeBitcoinInput}
keyboardType="numeric"
returnKeyType="done"
placeholder={`${minSpendableFormatted} to ${maxSpendableFormatted}`}
style={style.input}
/>
}
<Button
onPress={cancel}
style={{
marginRight: 10,
}}
danger
small={true}
>
<Text>Cancel</Text>
</Button>
</View>
</Body>
</CardItem>
</Card>
</Blurmodal>
</KeyboardAvoidingView>
);
}

Expand Down
11 changes: 8 additions & 3 deletions src/windows/LNURL/index.tsx
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
import React from "react"
import { createStackNavigator } from "@react-navigation/stack";
import { createStackNavigator, StackNavigationOptions } from "@react-navigation/stack";

import useStackNavigationOptions from "../../hooks/useStackNavigationOptions";
import AuthRequest from "./AuthRequest";
import ChannelRequest from "./ChannelRequest";
import WithdrawRequest from "./WithdrawRequest";
Expand All @@ -17,13 +18,17 @@ export type ReceiveStackParamList = {
}

export default function LNUURLIndex() {
const screenOptions: StackNavigationOptions = {
...useStackNavigationOptions(),
};

return (
<Stack.Navigator initialRouteName="default" screenOptions={{ cardStyle: { backgroundColor:"transparent"}, headerShown: false, animationEnabled: false }}>
<Stack.Navigator initialRouteName="default" screenOptions={screenOptions}>
<Stack.Screen name="default">{() => (<></>)}</Stack.Screen>
<Stack.Screen name="AuthRequest" component={AuthRequest} />
<Stack.Screen name="ChannelRequest" component={ChannelRequest} />
<Stack.Screen name="WithdrawRequest" component={WithdrawRequest} />
<Stack.Screen name="PayRequest" component={PayRequest} />
</Stack.Navigator>
)
}
}
5 changes: 5 additions & 0 deletions src/windows/Send/SendCamera.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@ export default function SendCamera({ navigation, route }: ISendCameraProps) {
const [cameraType, setCameraType] = useState<"front" | "back">("back");
const [scanning, setScanning] = useState(true);
const setLNURL = useStoreActions((store) => store.lnUrl.setLNUrl)
const resolveLightningAddress = useStoreActions((store) => store.lnUrl.resolveLightningAddress)
const lnurlClear = useStoreActions((store) => store.lnUrl.clear);
const [cameraActive, setCameraActive] = useState(route.params?.viaSwipe ?? true);

Expand Down Expand Up @@ -124,6 +125,10 @@ export default function SendCamera({ navigation, route }: ISendCameraProps) {
lnurlClear();
}
} catch (e) { }
} else if (paymentRequest.includes("@")) {
if (await resolveLightningAddress(paymentRequest)) {
gotoNextScreen("LNURL", { screen: "PayRequest" }, false);
}
}
else {
try {
Expand Down
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