Replying to Avatar Renaud Lifchitz

This is a temporary hosted PoC:

https://n8n.primedomain.fr/form/cbb4afa9-1e2e-4705-adb1-e09f37d7811c

Have fun or fright! 😉

cc nostr:nprofile1qyvhwue69uhkyat8d4skutndva6hjtnwv46r5dpcxsuqz9nhwden5te0vfjhgcfwdehhxarjd9kzucmpd5qzqxvfqd89dw8kqmrjfaz6zt8gfggcg93p4tm3s2slv4jrszuugfmt74rjkj

In a nutshell, from the victim LN address, we can easily find its Spark on-chain address throught LNURL "well-known" URL, for example:

https://walletofsatoshi.com/.well-known/lnurlp/warmestfuture710

From here, we can browse all the address details on a blockchain explorer like:

https://www.sparkscan.io/address/spark1pgss9gqjlk5emnuwg9dvxdh76r70ny2nmumhnzlth6q4zr0hych72gerqux6vp?network=mainnet

Conclusion: Everything is public... 🤬

cc nostr:nprofile1qyvhwue69uhkyat8d4skutndva6hjtnwv46r5dpcxsuqz9nhwden5te0vfjhgcfwdehhxarjd9kzucmpd5qzqxvfqd89dw8kqmrjfaz6zt8gfggcg93p4tm3s2slv4jrszuugfmt74rjkj nostr:nprofile1qythwumn8ghj7ct5d3shxtnwdaehgu3wd3skuep0qyt8wumn8ghj7etyv4hzumn0wd68ytnvv9hxgtcqyqxzfcer2g508mjnd8223frw4yhj3udg8ymducdvddqq84qrgn2zyd6ur5w

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Discussion

Wild! Thanks for sharing this.

nostr:npub1renaud65zug8r570ndztde2xhk206z3v50a5mwa3kp2xshy3zmjqkqaw97 I emailed nostr:npub1hcwcj72tlyk7thtyc8nq763vwrq5p2avnyeyrrlwxrzuvdl7j3usj4h9rq yesterday about this and here’s the response I got back:

“We were testing a beta feature with the Spark address/LNURL, but it is no longer required. We've removed the Spark address from that location now.”

Sounds like this privacy leak is getting patched in the next update. Let me know if you find anything else and I’ll forward it on.

Removing the Spark address from the "well-known" LNURL address doesn't solve anything. Monitoring sparkscan.io for a given amount (for example sending 1 sat to a LN address) is enough to uncover the Spark address from the LN address... It's security by obscurity, nothing more! 🤡

Anyway, thanks for reporting them the issue, but it cannot be solved while they stay on a plaintext blockchain...

Damn it man, don’t make me into a Monero maxi.

Solution is easy: stay on Lightning, not on a side-chain...

It’s not technically a sidechain, it’s kind of a different concept than something like Liquid but it still serves the same functional purpose of a public ledger that can handle micropayments. Lightning is the connection layer but most people will never run it due to the complexity, so they will end up sacrificing privacy for convenience and ease of use.

Interested by their answer if you forward them my remark about their "fix"... 😉

I don’t know how that can be solved if each wallet has a static public key that can’t be abstracted away by design.

Not only public -- but Lightspark has the IP address and user-agent of this user, which they can granularly associate with each transaction. Crazy.

Is it safe to say that all Spark-enabled wallets have this issue? What are the others?