Viewing a response to: @jl777/bitcoin-spinoff-fork-how-to-make-a-clean-fork-without-any-replay-attack-and-no-blockchain-visible-changes
Where in the Core code does the SIGHASH `int` get truncated to 1 byte before signing?
| author | pinhead26 |
|---|---|
| permlink | re-jl777-bitcoin-spinoff-fork-how-to-make-a-clean-fork-without-any-replay-attack-and-no-blockchain-visible-changes-20160818t221710952z |
| category | bitcoin |
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| created | 2016-08-18 22:17:09 |
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| root_title | "bitcoin spinoff fork - how to make a clean fork without any replay attack and no blockchain visible changes" |
| beneficiaries | [] |
| max_accepted_payout | 1,000,000.000 HBD |
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HASH(the modified tx with the 4 byte sighash int) -> 256 bits that is signed then the SIGHASH byte (not int) is concatenated to the signature and that is what goes in the blockchain. it is explained in the http://bitcoinfactswiki.github.io/OP_CHECKSIG/
| author | jl777 |
|---|---|
| permlink | re-pinhead26-re-jl777-bitcoin-spinoff-fork-how-to-make-a-clean-fork-without-any-replay-attack-and-no-blockchain-visible-changes-20160818t231059861z |
| category | bitcoin |
| json_metadata | {"tags":["bitcoin"],"links":["http://bitcoinfactswiki.github.io/OP_CHECKSIG/"]} |
| created | 2016-08-18 23:10:57 |
| last_update | 2016-08-18 23:10:57 |
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| cashout_time | 1969-12-31 23:59:59 |
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| root_title | "bitcoin spinoff fork - how to make a clean fork without any replay attack and no blockchain visible changes" |
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| max_accepted_payout | 1,000,000.000 HBD |
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Right that's what I meant sorry, 4 bytes are signed but only 1 byte goes into the serialized transaction for broadcast. So what I'm asking is, where in the Tx serialization process is the 4 bytes reduced to 1? Like literally where in the code or protocol spec?
| author | pinhead26 |
|---|---|
| permlink | re-jl777-re-pinhead26-re-jl777-bitcoin-spinoff-fork-how-to-make-a-clean-fork-without-any-replay-attack-and-no-blockchain-visible-changes-20160818t232451363z |
| category | bitcoin |
| json_metadata | {"tags":["bitcoin"]} |
| created | 2016-08-18 23:24:51 |
| last_update | 2016-08-18 23:24:51 |
| depth | 3 |
| children | 3 |
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| cashout_time | 1969-12-31 23:59:59 |
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| author_reputation | 3,707,077 |
| root_title | "bitcoin spinoff fork - how to make a clean fork without any replay attack and no blockchain visible changes" |
| beneficiaries | [] |
| max_accepted_payout | 1,000,000.000 HBD |
| percent_hbd | 10,000 |
| post_id | 879,806 |
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the signature is generated, 70 to 72 bytes (maybe I am off by 1 here), and the sighash byte is just added to the end. It is in the protocol spec, so that is what I did and it works. not familiar with bitcoind code as I wrote iguanacore from scratch
| author | jl777 |
|---|---|
| permlink | re-pinhead26-re-jl777-re-pinhead26-re-jl777-bitcoin-spinoff-fork-how-to-make-a-clean-fork-without-any-replay-attack-and-no-blockchain-visible-changes-20160818t234635928z |
| category | bitcoin |
| json_metadata | {"tags":["bitcoin"]} |
| created | 2016-08-18 23:46:36 |
| last_update | 2016-08-18 23:46:36 |
| depth | 4 |
| children | 1 |
| last_payout | 2016-09-18 08:42:33 |
| cashout_time | 1969-12-31 23:59:59 |
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| root_title | "bitcoin spinoff fork - how to make a clean fork without any replay attack and no blockchain visible changes" |
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| max_accepted_payout | 1,000,000.000 HBD |
| percent_hbd | 10,000 |
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yes, you found it. casting an int to char will truncate it
| author | jl777 |
|---|---|
| permlink | re-pinhead26-re-jl777-re-pinhead26-re-jl777-bitcoin-spinoff-fork-how-to-make-a-clean-fork-without-any-replay-attack-and-no-blockchain-visible-changes-20160819t005941796z |
| category | bitcoin |
| json_metadata | {"tags":["bitcoin"]} |
| created | 2016-08-19 00:59:42 |
| last_update | 2016-08-19 00:59:42 |
| depth | 4 |
| children | 0 |
| last_payout | 2016-09-18 08:42:33 |
| cashout_time | 1969-12-31 23:59:59 |
| total_payout_value | 0.000 HBD |
| curator_payout_value | 0.000 HBD |
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| author_reputation | 14,988,697,980,664 |
| root_title | "bitcoin spinoff fork - how to make a clean fork without any replay attack and no blockchain visible changes" |
| beneficiaries | [] |
| max_accepted_payout | 1,000,000.000 HBD |
| percent_hbd | 10,000 |
| post_id | 881,023 |
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