Provably burning Monero

Question

Is it possible to provably burn Monero? Does its use mandatory ring signatures and stealth addressing make proving that Monero was sent to a "burn address" impossible to verify?

If proof of burn is possible with Monero, how can it be done?

Answer 1

One way to do this is to use a very large unlock time. An unlock time value is either a block number (you can select one as large as ~1900 years from now, which is arguably not burned forever, especially if block time changes) or a UNIX time (you can then lock it for about 292 billion years, which should be enough for most purposes).

Another way would be to make a new address with a "funny looking" address, that corresponds to a normal view key part, and a public spend key that's so specific that it was obviously crafted, rather than derived from a private spend key. You can then be sure that the private spend key is unknown. You then send the burned monero to that address, and make the view key public. Since the view key is normal, people will see the incoming monero, but since the private spend key is unknown, nobody will be able to spend those. This is the typical way Bitcoin derivatives burn coins.

Answer 2

luigi1111 from the Monero Core Team made a "burn address" a while ago,

Address: 42aaBurnXMRBurnBurnXMRBurnBurnXMRBurnBurnXMR13DXCDQWwCATBednqL7EKiXejT55RDHdzPCmxid66QRLMugnw2G

Viewkey: 1ac191890bc6ae9fe3a8115e83263abce1f020144ee7e5254e14efb9dcea8105