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Correcting the hexadecimal of the DOCPROOF identifier

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Minh T. Nguyen 2014-06-25 22:46:55 -07:00
parent be23e23bd7
commit e4c1a740c3
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ch05.asciidoc
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@ -373,7 +373,7 @@ OP_RETURN scripts look like this:
OP_RETURN <data>
----
where the data portion is limited to 40 bytes and most often represents a hash, such as the output from the SHA256 algorithm (32 bytes). Many applications put a prefix in front of the data to help identify the application. For example, the proofofexistence.com digital notarization service uses the 8-byte prefix "DOCPROOF" which is ASCII encoded as 444350524f4f46 in hexadecimal.
where the data portion is limited to 40 bytes and most often represents a hash, such as the output from the SHA256 algorithm (32 bytes). Many applications put a prefix in front of the data to help identify the application. For example, the proofofexistence.com digital notarization service uses the 8-byte prefix "DOCPROOF" which is ASCII encoded as 444F4350524F4F46 in hexadecimal.
Keep in mind that there is no "unlocking script" that corresponds to OP_RETURN, that can be used to "spend" an OP_RETURN output. The whole point of OP_RETURN is that you can't spend the money locked in that output and therefore it does not need to be held in the UTXO set as potentially spendable - OP_RETURN is _provably un-spendable_. OP_RETURN is usually an output with a zero bitcoin amount, since any bitcoin assigned to such an output is effectively lost forever. If an OP_RETURN is encountered by the script validation software, it results immediately in halting the execution of the validation script and marking the transaction as invalid. Thus, if you accidentally reference an OP_RETURN output as an input in a transaction, that transaction is invalid.