mirror of
https://github.com/bitcoin/bips.git
synced 2025-02-23 15:20:50 +01:00
Merge pull request #1319 from JeremyRubin/119-syntax
[BIP-119] Use mediawiki syntax highlighting, add comment to spec
This commit is contained in:
Luke Dashjr
GitHub
commit
43a48ec0bf
1 changed files with 100 additions and 57 deletions
|
|
@ -66,31 +66,40 @@ OP_CHECKTEMPLATEVERIFY as implemented in C++ in the context of Bitcoin Core can
|
|||
be seen in the reference implementation.
|
||||
|
||||
The execution of the opcode is as follows:
|
||||
def execute_bip_119(self):
|
||||
# Before soft-fork activation / failed activation
|
||||
if not self.flags.script_verify_default_check_template_verify_hash:
|
||||
# Potentially set for node-local policy to discourage premature use
|
||||
if self.flags.script_verify_discourage_upgradable_nops:
|
||||
return self.errors_with(errors.script_err_discourage_upgradable_nops)
|
||||
return self.return_as_nop()
|
||||
# CTV always requires at least one stack argument
|
||||
if len(self.stack) < 1:
|
||||
return self.errors_with(errors.script_err_invalid_stack_operation)
|
||||
# CTV only verifies the hash against a 32 byte argument
|
||||
if len(self.stack[-1]) == 32:
|
||||
# Ensure the precomputed data required for anti-DoS is available,
|
||||
# or cache it on first use
|
||||
if self.context.precomputed_ctv_data == None:
|
||||
self.context.precomputed_ctv_data = self.context.tx.get_default_check_template_precomputed_data()
|
||||
if stack[-1] != self.context.tx.get_default_check_template_hash(self.context.nIn, self.context.precomputed_ctv_data)
|
||||
return self.errors_with(errors.script_err_template_mismatch)
|
||||
return self.return_as_nop()
|
||||
# future upgrade can add semantics for this opcode with different length args
|
||||
# so discourage use when applicable
|
||||
<source lang="python">
|
||||
def execute_bip_119(self):
|
||||
# Before soft-fork activation / failed activation
|
||||
# continue to treat as NOP4
|
||||
if not self.flags.script_verify_default_check_template_verify_hash:
|
||||
# Potentially set for node-local policy to discourage premature use
|
||||
if self.flags.script_verify_discourage_upgradable_nops:
|
||||
return self.errors_with(errors.script_err_discourage_upgradable_nops)
|
||||
else:
|
||||
return self.return_as_nop()
|
||||
return self.return_as_nop()
|
||||
|
||||
# CTV always requires at least one stack argument
|
||||
if len(self.stack) < 1:
|
||||
return self.errors_with(errors.script_err_invalid_stack_operation)
|
||||
|
||||
# CTV only verifies the hash against a 32 byte argument
|
||||
if len(self.stack[-1]) == 32:
|
||||
# Ensure the precomputed data required for anti-DoS is available,
|
||||
# or cache it on first use
|
||||
if self.context.precomputed_ctv_data == None:
|
||||
self.context.precomputed_ctv_data = self.context.tx.get_default_check_template_precomputed_data()
|
||||
|
||||
# If the hashes do not match, return error
|
||||
if stack[-1] != self.context.tx.get_default_check_template_hash(self.context.nIn, self.context.precomputed_ctv_data)
|
||||
return self.errors_with(errors.script_err_template_mismatch)
|
||||
|
||||
return self.return_as_nop()
|
||||
|
||||
# future upgrade can add semantics for this opcode with different length args
|
||||
# so discourage use when applicable
|
||||
if self.flags.script_verify_discourage_upgradable_nops:
|
||||
return self.errors_with(errors.script_err_discourage_upgradable_nops)
|
||||
else:
|
||||
return self.return_as_nop()
|
||||
</source>
|
||||
|
||||
The computation of this hash can be implemented as specified below (where self
|
||||
is the transaction type). Care must be taken that in any validation context,
|
||||
|
|
@ -101,46 +110,80 @@ including hashes of the scriptsigs, sequences, and outputs. See the section
|
|||
"Denial of Service and Validation Costs" below. This is not a performance
|
||||
optimization.
|
||||
|
||||
def get_default_check_template_precomputed_data(self):
|
||||
result = {}
|
||||
# If there are no scriptSigs we do not need to precompute a hash
|
||||
if any(inp.scriptSig for inp in self.vin):
|
||||
result["scriptSigs"] = sha256(b"".join(ser_string(inp.scriptSig) for inp in self.vin))
|
||||
# The same value is also pre-computed for and defined in BIP-341 and can be shared
|
||||
result["sequences"] = sha256(b"".join(struct.pack("<I", inp.nSequence) for inp in self.vin))
|
||||
# The same value is also pre-computed for and defined in BIP-341 and can be shared
|
||||
result["outputs"] = sha256(b"".join(out.serialize() for out in self.vout))
|
||||
return result
|
||||
<source lang="python">
|
||||
|
||||
# parameter precomputed must be passed in for DoS resistance
|
||||
def get_default_check_template_hash(self, nIn, precomputed = None):
|
||||
if precomputed == None:
|
||||
precomputed = self.get_default_check_template_precomputed_data()
|
||||
def ser_compact_size(l):
|
||||
r = b""
|
||||
if l < 253:
|
||||
# Serialize as unsigned char
|
||||
r = struct.pack("B", l)
|
||||
elif l < 0x10000:
|
||||
# Serialize as unsigned char 253 followed by unsigned 2 byte integer (little endian)
|
||||
r = struct.pack("<BH", 253, l)
|
||||
elif l < 0x100000000:
|
||||
# Serialize as unsigned char 254 followed by unsigned 4 byte integer (little endian)
|
||||
r = struct.pack("<BI", 254, l)
|
||||
else:
|
||||
# Serialize as unsigned char 255 followed by unsigned 8 byte integer (little endian)
|
||||
r = struct.pack("<BQ", 255, l)
|
||||
return r
|
||||
|
||||
def ser_string(s):
|
||||
return ser_compact_size(len(s)) + s
|
||||
|
||||
class CTxOut:
|
||||
def serialize(self):
|
||||
r = b""
|
||||
# pack as 4 byte signed integer
|
||||
r += struct.pack("<i", self.nVersion)
|
||||
# pack as 4 byte unsigned integer
|
||||
r += struct.pack("<I", self.nLockTime)
|
||||
# we do not include the hash in the case where there is no
|
||||
# scriptSigs
|
||||
if "scriptSigs" in precomputed:
|
||||
r += precomputed["scriptSigs"]
|
||||
# pack as 4 byte unsigned integer
|
||||
r += struct.pack("<I", len(self.vin))
|
||||
r += precomputed["sequences"]
|
||||
# pack as 4 byte unsigned integer
|
||||
r += struct.pack("<I", len(self.vout))
|
||||
r += precomputed["outputs"]
|
||||
# pack as 4 byte unsigned integer
|
||||
r += struct.pack("<I", nIn)
|
||||
return sha256(r)
|
||||
# serialize as signed 8 byte integer (little endian)
|
||||
r += struct.pack("<q", self.nValue)
|
||||
r += ser_string(self.scriptPubKey)
|
||||
return r
|
||||
|
||||
def get_default_check_template_precomputed_data(self):
|
||||
result = {}
|
||||
# If there are no scriptSigs we do not need to precompute a hash
|
||||
if any(inp.scriptSig for inp in self.vin):
|
||||
result["scriptSigs"] = sha256(b"".join(ser_string(inp.scriptSig) for inp in self.vin))
|
||||
# The same value is also pre-computed for and defined in BIP-341 and can be shared.
|
||||
# each nSequence is packed as 4 byte unsigned integer (little endian)
|
||||
result["sequences"] = sha256(b"".join(struct.pack("<I", inp.nSequence) for inp in self.vin))
|
||||
# The same value is also pre-computed for and defined in BIP-341 and can be shared
|
||||
# See class CTxOut above for details.
|
||||
result["outputs"] = sha256(b"".join(out.serialize() for out in self.vout))
|
||||
return result
|
||||
|
||||
# parameter precomputed must be passed in for DoS resistance
|
||||
def get_default_check_template_hash(self, nIn, precomputed = None):
|
||||
if precomputed == None:
|
||||
precomputed = self.get_default_check_template_precomputed_data()
|
||||
r = b""
|
||||
# Serialize as 4 byte signed integer (little endian)
|
||||
r += struct.pack("<i", self.nVersion)
|
||||
# Serialize as 4 byte unsigned integer (little endian)
|
||||
r += struct.pack("<I", self.nLockTime)
|
||||
# we do not include the hash in the case where there is no
|
||||
# scriptSigs
|
||||
if "scriptSigs" in precomputed:
|
||||
r += precomputed["scriptSigs"]
|
||||
# Serialize as 4 byte unsigned integer (little endian)
|
||||
r += struct.pack("<I", len(self.vin))
|
||||
r += precomputed["sequences"]
|
||||
# Serialize as 4 byte unsigned integer (little endian)
|
||||
r += struct.pack("<I", len(self.vout))
|
||||
r += precomputed["outputs"]
|
||||
# Serialize as 4 byte unsigned integer (little endian)
|
||||
r += struct.pack("<I", nIn)
|
||||
return sha256(r)
|
||||
</source>
|
||||
|
||||
|
||||
A PayToBareDefaultCheckTemplateVerifyHash output matches the following template:
|
||||
|
||||
# Extra-fast test for pay-to-basic-standard-template CScripts:
|
||||
def is_pay_to_bare_default_check_template_verify_hash(self):
|
||||
return len(self) == 34 and self[0] == 0x20 and self[-1] == OP_CHECKTEMPLATEVERIFY
|
||||
<source lang="python">
|
||||
# Extra-fast test for pay-to-basic-standard-template CScripts:
|
||||
def is_pay_to_bare_default_check_template_verify_hash(self):
|
||||
return len(self) == 34 and self[0] == 0x20 and self[-1] == OP_CHECKTEMPLATEVERIFY
|
||||
</source>
|
||||
|
||||
|
||||
==Deployment==
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue