Oddbean new post about login | logout you can do this without putting anything onchain by using silent payments and an encrypted note on nostr that lets the recipient know what output is being spent. much nicer for utxo privacy.
nostr:nevent1qqswtd2p6uwdh3kfph88yeqf9ccx3qvawl66wwtlh9dzwmylfuk0cvqpz9mhxue69uhkummnw3ezuamfdejj7q3qxtscya34g58tk0z605fvr788k263gsu6cy9x0mhnm87echrgufzsxpqqqqqqzddwqht nostr:nevent1qqsrxp52tx73dgqf4g9da0pldzh3s7pv82yk9l8u3fam2tvjwtgx3fcprfmhxue69uhhyetvv9ujuam9d3kx7unyv4ezumn9wshsygx70mx3u2tk56km9la97ndcrf7cztytke5c4gqdeu08dtd4tm7kg5psgqqqqqqsyygrcs