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([2a01:cb1d:44:6500:9d6d:71b2:cb71:cb17]) by smtp.googlemail.com with ESMTPSA id l18sm24535680wrh.54.2019.05.26.14.17.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 26 May 2019 14:17:30 -0700 (PDT) To: Johnson Lau References: <6DFB6C65-D123-40FD-9CE3-49FFCA81EE46@xbt.hk> <253DB697-BECF-4D68-8A1E-1549B52D5AFA@xbt.hk> From: Aymeric Vitte Openpgp: preference=signencrypt Autocrypt: addr=vitteaymeric@gmail.com; prefer-encrypt=mutual; keydata= mQINBFdW8uABEAC7HJScbB2d/lmYoY5Cn9loEjJwfLs1LC3om030bWFGiH3Ceo5XeHUT94rw Pi+HaHU8ea94425SXIFsnqp/ouoT/8Ffn6vED0OoRmK0jE4fqDApXSpoL2mHX9PAGdUItMtD YrxBiBZNfMkctEsm4NrQ4TCvB3Yrm6Fc69inXJjUoYgPw5tHafEeI8Qwh0j99JZZDKcAqIra JF3MPc59rATz0qOJtRP9EpsPVFwjJe13zN6CHILwiVgrL8EtT5WKCVO6ATxh60LHi8+MwPxV V31zp/NNI5Hck+XocEMO98ZvUu9X8ZxmnOk/+9pBxXEwUqSGUNWdmPJLncpI23Usce3u/MOo M2C4T4rD4J0XrXiyBvbeTvwq4qVNlyggeWzlBH+YpEYgDctPq4gNh4eoTtAkf8URtBeke5bQ CGdaZt/jxv8nvmxs9V/iSyg5ldJLQktHStXOo0OZ7FEB2C6Ggtymm4hm2MHYg07Q1MGJrFLa oJZkJ3JeXnVsZMam7ypQtld6rRa96CvH+llXwux6aQ5hKdzmBBMQ10LlkZhkExgTawbeqdiG RMP2DjD5go6TPdAHS4NN34SBkrTWLqgWOjN/lnG77bbLnpMl0P+xBTuqw1oSXaDbcdHE2nGY lRno/ZZIfr+1Bq56DZLBX/WpnAT4f5WtofL4CxQM9SbG6byyewARAQABtCJBeW1lcmljIFZp dHRlIDxheW1lcmljQHBlZXJzbS5jb20+iQI/BBMBCAApBQJXVvLgAhsjBQkJZgGABwsJCAcD AgEGFQgCCQoLBBYCAwECHgECF4AACgkQKh17NCYnrDm3WhAAlYmgtSmtfqjBvQMqkmtqiQJA aZkzFZWt6+zroduHH5/Tp8jh73gFqCUyRrl/kcKvs2+XQhfrOwk1R6OScF25bpnrZSeuyJnZ MZu4T0P2tGS8YdddQvWUHMtI9ZnQRuYmuZT23/hgj1JnukuGvGLeY0yDUa1xFffPN39shp5X FPMcpIVOV3bs+xjAdsyfRyO3qJAD1FGiR7ggJeoaxUbKZ6NtcVUPPRMjVTKfopkuDwKY318m BE0epfxSZ/iRhsJ0/sREUWgbgq4/QvCFwBKzgz7fTikGmf8OELWSdofmXs7gOtmMc3el8fJu W8PVa/OsIQHDmwSzvxmE8ba5M8bdwOYEraTWFArIymAAtRXKxmuYpkqKfeSlbCwae3W+pgNT 8nKYRVAFlMtIxYkmPYyMTk9kCscmSqugGWbWdnqe/dhVaa31xa1qO1tDH24D2/tjCJRQt4Jk AEWNSmjCmjfeArMEFTGlZwMTAjVXErLSPbLOsZiZhD9sjvSbfzrtJiMli2h9+Dvds+AJk1PM O8LW7cCNyFoCk4OdAxzJHobZ25G+uy4NSQEHgxLC2iuh/tugz1tOHnQczPc/3AkVVI9A5DF1 gbVRBJh6rI7sAcwuR76uoOs0Rpp7r6I66xqU/5eq8g1OsJp89tw0ppSIa0YmaxNqQZ0l3rVX o/ZwpBjtNQS5Ag0EV1by4AEQANhlz3Ywff4dY1HTdn05v0wVUxZzW2PUih+96m6EhpUrD9BT vxriKtbgxm/zl+5YAlThbrk9f0QyVTHJ95Z1/M5qjuksP9Zn3qZ/8ylANDkN2s3z8Bq/LJA+ u7+APhMqyFWK0FqNCOogClvijiKPEzkU6tmDGO6wZ5pR/u8Fdq7DGQgwgyGZZc7qstte0M7l yx7bVRlPBqvd6kyX3YubQHzkctf46nFjiYZgKawdWFsA3PCdSBupbhixL5d/t1UK9ZTiQJcf 0uhHzT06qwolFrm/ugkLDHtE4Zo3BuKch47Sms8P2hJ08gABxeJHg0ZgkIUy/Xf4nHbDCBJw T8tE8pWYWA2ECiPNo0TOCMVOueEzISUNKINfCuFHSbMQU39hgt3ofxODbAjOiO3e/iu1ptck AkuVBdtjOBP4tHRGxVrbf5EuAV5U5xtiSxMwMgojg0GIXZjnT/8uvWqcLqtJILRMmmu+WNvD oxuiJzcTJhDai9oujmxQwcpMvgrBB89KSTDyitO5XVjZqaR7Zxvvn3rM4bAms/lotv9+pTyh spazTIxb80u0ifJ6y1RxAkxQCfWwps1i3VbsM6OKX78aUyOf5V4ihXF57M37tOqPRwFvz6a+ AIIhUNMTLo2H+o6Vw9qbX8SUxPHPs6YpJ8lWQJ9OMWHE+SbaDFAi/D5hYRubABEBAAGJAiUE GAEIAA8FAldW8uACGwwFCQlmAYAACgkQKh17NCYnrDmk4Q/9Fuu0h5HvIiO3ieYA2StdE7hO vv2THuesjJDsj6aQUTgknaxKptJogNe3dDyIT+FHxXmCw0Nrbm9Q3ryl80z/G9utfFNO3Gwc q31QW3n3LJHnpqdrV3WsRzT5NwJMVtiIAGRrX8ZomtarWHT0PeEHC2xBdFzRrJtmkrwer0Wc 0nBzD7vk1XEXC9nODbmlgsesoHFgRwQBst3wClCbX1gv8aSfxQNpaf9UBC8DmyrQ621UXpBo PvcFEtWxV44vJfP0WOLCCN0Pzv2F2I66iKo7VMqbr5jlNAXJN9I1hXb7qwYJmBC9j5oeEoqv A9d44WWpxrdAr8qih4Nv89k9+9F6NoqORY3FGuVDKiW8CVhCmGT7bIvNeyicVBZFipXqPcKL VFduO2c5Ubc2npMWLUF1k9JJc9tH75l3+F/0RbYVTzGAZ+zSaudwR6h8YiCN2DBZGZkJEZbh 3X/l6jtijMN/W9sPHyyKvm/TmeEC27S3TqZPZ8PUQLxZC70V6gMbenh01JdSQsn5t8Ru0RNh Blt0g7IyZyIKCE9b+TyzbYpX6qgqEBUHia5b0vyPtQacWQlZ8uqnghAqNkLluEsy7Q/7xG6M wXUYEDsFOmB9dKOzcAOIhpxlVjSKu5mzXJ11sEtE8nyF5NJ/riCA7FGcjlki3zIpzQUNo9v7 vXl2h6Tivlk= Message-ID: <6d6766da-67fb-31e1-eceb-663bffeef74a@gmail.com> Date: Sun, 26 May 2019 23:17:30 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.3; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: fr X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Mon, 27 May 2019 14:28:45 +0000 Cc: bitcoin-dev , me@thomaskerin.io, Pieter Wuille Subject: Re: [bitcoin-dev] Two questions about segwit implementation X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 26 May 2019 21:17:34 -0000 Well, OK, then back to non standard stuff and bitcoin considers that an OP_1 or empty scriptpubkey is something that can exist, sipa does not like my questions on this list but this is a bit frightening in fact to see that after 10 years an OP_1 scriptpubkey or empty one can be a use case, thanks Thomas also, where all of this is clearly documented so people don't bother the list not to produce approximative stuff remains mysterious Le 26/05/2019 à 19:24, Johnson Lau a écrit : > Empty scriptSig doesn’t imply segwit input: if the previous scriptPubKey is OP_1 (which does not allow witness), it could still be spent with an empty scriptSig > > Similarly, a scriptSig looking like a spend of P2SH-segwit doesn’t imply segwit input: if the previous scriptPubKey is empty, it could be spent with a push of any non-zero value. > >> On 27 May 2019, at 1:09 AM, Aymeric Vitte wrote: >> >> I did not phrase correctly in fact, what I meant is: if the validator >> sees empty or witness script in scriptSig, then this is a segwit input, >> and doing this one by one the validator can associate the correct segwit >> data to the correct segwit input, so 00 does not look to be needed >> >> Le 26/05/2019 à 18:28, Johnson Lau a écrit : >>> This is not how it works. While the transaction creator may know which inputs are segwit, the validators have no way to tell until they look up the UTXO set. >>> >>> In a transaction, all information about an input the validators have is the 36-byte outpoint (txid + index). Just by looking at the outpoint, there is no way to tell whether it is segwit-enabled or not. So there needs to be a way to tell the validator that “the witness for this input is empty”, and it is the “00”. >>> >>>> On 27 May 2019, at 12:18 AM, Aymeric Vitte wrote: >>>> >>>> ……. for the 00 number of witness >>>> data for non segwit inputs the one that is doing the transaction knows >>>> which inputs are segwit or not, then parsing the transaction you can >>>> associate the correct input to the correct witness data, without the >>>> need of 00, so I must be missing the use case >