BIP: ZZZ
Layer: Consensus (soft fork)
Title: OP_PUSHTXDATA
Author: Johnson Lau <jl2012@xbt.hk>
Comments-Summary: No comments yet.
Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0ZZZ
Status: Draft
Type: Standards Track
Created: 2017-07-19
License: BSD-3-Clause
CC0-1.0
This BIP defines a new operation OP_PUSHTXDATA in Merklized Script Version 0.
Covenant: outputs must follow a pre-specified pattern
Vault: require an extra step to spend deep cold storage
Fine-tuned transaction signing, e.g. "fees must be at least 100 satoshis per weight unit", "number of outputs must not be bigger than number of inputs", "signing only 2 outputs", "values of outputs X and Y must not be the same"
(To be completed)
The following specification is applicable to scriptKeyCode of MSV0, and scriptWitCode for MSV0 and P2WPKV0.
A new operation OP_PUSHTXDATA is defined, with the value of 0xbb. The top stack item MUST be a CScriptNum from 0 to 15 or the evaluation fails. The value determines the type of TXDATA to be pushed. If the TXDATA type is smaller than 10, it is removed from the stack and a single value is returned to the top of stack. All values returned are CScriptNum.
TXDATA type
| Name | Value returned to stack |
|---|---|---|
| 0 |
TXDATA_THIS_VIN_INDEX
| Index of the current input |
| 1 |
TXDATA_VIN_SIZE
| Number of inputs in the transaction |
| 2 |
TXDATA_VOUT_SIZE
| Number of outputs in the transaction |
| 3 |
TXDATA_THIS_VIN_VALUE
| Value of the current input (in satoshi) |
| 4 |
TXDATA_FEE
| The fees paid by the transaction (in satoshi) |
| 5 |
TXDATA_VERSION
|
Transaction nVersion cast to an unsigned integer
|
| 6 |
TXDATA_LOCKTIME
|
Transaction nLockTime
|
| 7 |
TXDATA_BASE_SIZE
| Transaction size without witness serialization (in bytes) |
| 8 |
TXDATA_TOTAL_SIZE
| Transaction size with witness serialization (in bytes) |
| 9 |
TXDATA_WEIGHT
| Transaction weight |
If the TXDATA type is 10 or greater, the second highest stack item is a CScriptNum determining the index. The script MUST fail if the index value is smaller than -1. If the index value is -1, it is evaluated as index of the current input. The top two stack items are removed, and one or more items are returned to the stack according to the TXDATA type and index. If the specified input or output does not exist, the script MUST fail.
TXDATA type
| Name | First returned value | Second returned value | Third returned value |
|---|---|---|---|---|
| 10 |
TXDATA_VIN_PREVOUT
|
prevout hash of the specified input
|
prevout index of the specified input
| |
| 11 |
TXDATA_VIN_SEQUENCE
|
nSequence value of the specified input
| ||
| 12 |
TXDATA_VIN
|
prevout hash of the specified input
|
prevout index of the specified input
|
nSequence value of the specified input
|
| 13 |
TXDATA_VOUT_VALUE
| Value of the specified output | ||
| 14 |
TXDATA_VOUT_SCRIPTPUBKEY
|
scriptPubKey of the specified output
| ||
| 15 |
TXDATA_VOUT
| Value of the specified output (in satoshi) |
scriptPubKey of the specified output
|
For example, if the type is TXDATA_VIN, 2 items are removed from and 3 items are returned to the stack, with the nSequence as the final top stack value.
prevout index, nSequence, and output value are returned as <code>CScriptNum.
prevout hashes are returned as 32-byte little endian value, with the same byte sequence used in transaction serialization.
scriptPubKey are returned as the actual script. For example, if the scriptPubKey is P2WSH, the returned vector size is 34 bytes (0x0020{32 bytes hash}). If the size of scriptPubKey is bigger than 520 bytes, the script MUST fail.
As a soft fork, older software will continue to operate without modification. Non-upgraded nodes, however, will consider MSV0 and P2WPKV0 programs as anyone-can-spend scripts.
Exact details TBD.
https://github.com/jl2012/bitcoin/commits/vault
This document is dual licensed as BSD 3-clause, and Creative Commons CC0 1.0 Universal.