{"type":"rich","version":"1.0","author_name":"npub12p7jzesdg8kxdg8rujr20znnd868fgugczkwh4cyxwa6gnxj5sxsnjs309","author_url":"https://nostr.ae/npub12p7jzesdg8kxdg8rujr20znnd868fgugczkwh4cyxwa6gnxj5sxsnjs309","provider_name":"njump","provider_url":"https://nostr.ae","html":"📅 Original date posted:2017-09-07\n📝 Original message:After reading\nhttps://lists.linuxfoundation.org/pipermail/bitcoin-dev/2016-January/012194.html\nI see that Adam is correct. Unfortunately this SF would make Felix's\nconfidential transactions\nmore complicated. The blinding and unblinding transactions would have to\nbe created with\nminimal output values, and this will need to be considered when checking\nthat the fee is equal\nto the total amount of input. (it would now be SUM(inputs) -\nSUM(minimalOutputs))\n\nBlinding transaction:\n  Ins:\n    All non-confidential inputs are valid\n  Outs:\n  - 0..N: (new confidential outputs)\n    amount: 0\n    scriptPubkey: OP_2 \u003c0x{32-byte-hash-value}\u003e\n    witnessOut: \u003c0x{petersen-commitment}\u003e \u003c0x{range-proof}\u003e\n  - last:\n    amount: 0\n    scriptPubkey: OP_RETURN OP_2 {blinding-fee-amount}\n  Fee: Sum of the all inputs value\n\n\nHowever, looking at the format of the blinding transaction, and how the\nGCTXO is added to the UTXO set\nby miners, it seems that a change to the blinding scriptPubKey could\nallow for the use of 0 value\noutputs. Even with the SF proposed by this email thread.\n\nOP_RETURN could be added to the scriptPubKey during blinding. The amount\nand scriptPubKey destination of\nunblinded funds is part of the witness and the outputs of an unblinded\ntransaction are unspendable, so\nwhy not also make them unspendable in the blind transaction? As far as I\ncan tell those outputs don't need to\nbe spendable, they are really just encoding data. It doesn't seem like\nanything besides the confidential base\ntransaction and the fee output from the blind transaction need to be in\nthe UTXO set.\n\nIs it still possible to add this data to the witness if the scriptPubKey\nis unspendable? :\n\nwitnessOut: \u003c0x{petersen-commitment}\u003e \u003c0x{range-proof}\u003e\n\nI think I'm missing something obvious, someone point out why this is\nstupid please :)\n\nOn 09/06/2017 06:29 PM, Adam Back wrote:\n\u003e The pattern used by Felix Weiss' BIP for Confidential Transactions\n\u003e depends on or is tidier with 0-value outputs.\n\u003e\n\u003e Adam\n\u003e\n\u003e\n\u003e On 7 September 2017 at 00:54, CryptAxe via bitcoin-dev\n\u003e \u003cbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\u003e\u003e As long as an unspendable outputs (OP_RETURN outputs for example) with\n\u003e\u003e amount=0 are still allowed I don't see it being an issue for anything.\n\u003e\u003e\n\u003e\u003e On Sep 5, 2017 2:52 PM, \"Jorge Timón via bitcoin-dev\"\n\u003e\u003e \u003cbitcoin-dev at lists.linuxfoundation.org\u003e wrote:\n\u003e\u003e\u003e This is not a priority, not very important either.\n\u003e\u003e\u003e Right now it is possible to create 0-value outputs that are spendable\n\u003e\u003e\u003e and thus stay in the utxo (potentially forever). Requiring at least 1\n\u003e\u003e\u003e satoshi per output doesn't really do much against a spam attack to the\n\u003e\u003e\u003e utxo, but I think it would be slightly better than the current\n\u003e\u003e\u003e situation.\n\u003e\u003e\u003e\n\u003e\u003e\u003e Is there any reason or use case to keep allowing spendable outputs\n\u003e\u003e\u003e with null amounts in them?\n\u003e\u003e\u003e\n\u003e\u003e\u003e If not, I'm happy to create a BIP with its code, this should be simple.\n\u003e\u003e\u003e _______________________________________________\n\u003e\u003e\u003e bitcoin-dev mailing list\n\u003e\u003e\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e\u003e\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\u003e\u003e\n\u003e\u003e _______________________________________________\n\u003e\u003e bitcoin-dev mailing list\n\u003e\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\u003e\u003e"}