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drusselloctal@gmail.com 2014-10-30 14:03:19 -07:00
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@ -392,7 +392,7 @@ image::images/msbt_0504.png["Tx_Script_P2PubKeyHash_2"]
[[p2pk]]
==== Pay-to-Public-Key
Pay-to-Public-Key is a simpler form of a bitcoin payment than Pay-to-Public-Key-Hash. With this script form, the public key itself is stored in the locking script, rather than a public-key-hash as with P2PKH above, which is much shorter. Pay-to-Public-Key-Hash was invented by Satoshi to make bitcoin addresses shorter, for ease of use. Pay-to-Public-Key is now most often seen in coinbase transactions, generated by older mining software that has not been updated to use P2PKH.
Pay-to-Public-Key is a simpler form of a bitcoin payment than Pay-to-Public-Key-Hash. With this script form, the public key itself is stored in the locking script, rather than a public-key-hash as with P2PKH earlier, which is much shorter. Pay-to-Public-Key-Hash was invented by Satoshi to make bitcoin addresses shorter, for ease of use. Pay-to-Public-Key is now most often seen in coinbase transactions, generated by older mining software that has not been updated to use P2PKH.
A Pay-to-Public-Key locking script looks like this:
----
@ -404,17 +404,17 @@ The corresponding unlocking script that must be presented to unlock this type of
<Signature from Private Key A>
----
The combined script, which is validated by the transaction validation software is:
The combined script, which is validated by the transaction validation software, is:
----
<Signature from Private Key A> <Public Key A> OP_CHECKSIG
----
The script above is a simple invocation of the CHECKSIG operator which validates the signature as belonging to the correct key and returns TRUE on the stack.
This script is a simple invocation of the +CHECKSIG+ operator, which validates the signature as belonging to the correct key and returns TRUE on the stack.
[[multisig]]
==== Multi-Signature
Multi-signature scripts set a condition where N public keys are recorded in the script and at least M of those must provide signatures to release the encumbrance. This is also known as an M-of-N scheme, where N is the total number of keys and M is the threshold of signatures required for validation. For example, a 2-of-3 multi-signature is one where 3 public keys are listed as potential signers and at least 2 of those must be used to create signatures for a valid transaction to spend the funds. At this time, standard multi-signature scripts are limited to at most 15 listed public keys, meaning you can do anything from a 1-of-1 to a 15-of-15 multi-signature or any combination within that range. The limitation to 15 listed keys may be lifted by the time of publication of this book, so check the +isStandard()+ function to see what is currently accepted by the network.
Multi-signature scripts set a condition where N public keys are recorded in the script and at least M of those must provide signatures to release the encumbrance. This is also known as an M-of-N scheme, where N is the total number of keys and M is the threshold of signatures required for validation. For example, a 2-of-3 multi-signature is one where three public keys are listed as potential signers and at least two of those must be used to create signatures for a valid transaction to spend the funds. At this time, standard multi-signature scripts are limited to at most 15 listed public keys, meaning you can do anything from a 1-of-1 to a 15-of-15 multi-signature or any combination within that range. The limitation to 15 listed keys may be lifted by the time of publication of this book, so check the +isStandard()+ function to see what is currently accepted by the network.
The general form of a locking script setting an M-of-N multi-signature condition is:
@ -428,15 +428,16 @@ A locking script setting a 2-of-3 multi-signature condition looks like this:
2 <Public Key A> <Public Key B> <Public Key C> 3 OP_CHECKMULTISIG
----
The locking script above can be satisfied with an unlocking script containing pairs of signatures and public keys:
The preceding locking script can be satisfied with an unlocking script containing pairs of signatures and public keys:
----
OP_0 <Signature B> <Signature C>
----
or any combination of two signatures from the private keys corresponding to the three listed public keys.
_Note: The prefix OP_0 is required because of a bug in the original implementation of CHECKMULTISIG where one item too many is popped off the stack. It is ignored by CHECKMULTISIG and is simply a placeholder._
NOTE
The prefix +OP_0+ is required because of a bug in the original implementation of +CHECKMULTISIG+ where one item too many is popped off the stack. It is ignored by +CHECKMULTISIG+ and is simply a placeholder.
The two scripts together would form the combined validation script below:
The two scripts together would form the combined validation script:
----
OP_0 <Signature B> <Signature C>\
2 <Public Key A> <Public Key B> <Public Key C> 3 OP_CHECKMULTISIG