LNURLpay over Tor

Setup used

Raspiblitz on the dev branch (~v1.9.0rc3 - earlier versions should work)
CLN / LND with incoming capacity on public channel(s)
BTCPayServer v1.8.2 (an earlier version with LNaddress support should work)

Steps to create the service

Create user and log in
Create Store
Set up a Lightning Node
Paste the string from the Raspiblitz terminal menu CONNECT -> BTCPAY-CLN / BTCPAY-LND
Save and close
Click the Lightning Address under PLUGINS
Add Address (the part after the @ does not matter) eg:
```
[email protected]:23001
```

Create a Tor Hidden Service for the BTCPay HTTP port in the Raspiblitz terminal with this command:

config.scripts/tor.onion-service.sh btcpayhttp 80 23000

Example output:

# Hidden Service for btcpayhttp
HiddenServiceDir /mnt/hdd/tor/btcpayhttp
HiddenServiceVersion 3
HiddenServicePort 80 127.0.0.1:23000

Reloading Tor to activate the Hidden Service...

The Tor Hidden Service address for btcpayhttp is:
foj373kji26vs4ntlltxlizrqfzkd5kqc45jst5hc6ntwcrma5a5xxqd.onion
use with the port: 80

LN address over Tor

With the username and onion address put together the Lightning Address is ready:
```
oniontip@foj373kji26vs4ntlltxlizrqfzkd5kqc45jst5hc6ntwcrma5a5xxqd.onion
```

LNURLpay code

The URL to encode (as explained in https://github.com/andrerfneves/lightning-address/blob/master/README.md#tldr):

http://hidden-service.onion/.well-known/lnurlp/username

For this example:

http://foj373kji26vs4ntlltxlizrqfzkd5kqc45jst5hc6ntwcrma5a5xxqd.onion/.well-known/lnurlp/oniontip

Encode to base64 according to https://github.com/lnurl/luds/blob/luds/01.md. Can use https://lnurl.fiatjaf.com/codec/

Example result:

lnurl1dp68gup69uhkvmm2xvmnx6m2dyervannx3h8gmrvw3uxc6t6wfckv7ntvs6kkutrxs6k5um5x45xxdnww3mkxundvy6kzdtc0pckgtn0de5k7m309emk2mrv944kummhdchkcmn4wfk8qtm0de5k7mn5d9cqd8tcnf

To create a QR code in the Raspiblitz terminal use the command:

qr lnurl1dp68gup69uhkvmm2xvmnx6m2dyervannx3h8gmrvw3uxc6t6wfckv7ntvs6kkutrxs6k5um5x45xxdnww3mkxundvy6kzdtc0pckgtn0de5k7m309emk2mrv944kummhdchkcmn4wfk8qtm0de5k7mn5d9cqd8tcnf

Pay to the static LNURLpay code over onion

https://t.me/lightningtipbot now
Breez - in next release https://twitter.com/ubbabeck/status/1634580039286104064
Zeus - WIP draft: https://github.com/ZeusLN/zeus/pull/1349/files
Bitcoin Beach Wallet - feature request: https://github.com/GaloyMoney/galoy-mobile/issues/1441
More to come

openoms/btcpay-on-raspiblitz.md