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authorJohnson Lau <jl2012@xbt.hk>2020-09-11 14:34:02 -0700
committerPieter Wuille <pieter@wuille.net>2020-10-12 17:18:24 -0700
commit72422ce396b8eba7b1a72c171c2f07dae691d1b5 (patch)
treed2aa2a75ed54579ed6ddac8f858cf3ca67605b48 /src/script/interpreter.h
parent330de894a9a48515d9a473448b6c67adc3d188be (diff)
Implement Tapscript script validation rules (BIP 342)
This adds a new `SigVersion::TAPSCRIPT`, makes the necessary interpreter changes to make it implement BIP342, and uses them for leaf version 0xc0 in Taproot script path spends.
Diffstat (limited to 'src/script/interpreter.h')
-rw-r--r--src/script/interpreter.h29
1 files changed, 28 insertions, 1 deletions
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index 55aa1f230b..c0c2b012c6 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -86,6 +86,8 @@ enum
// "Exactly one stack element must remain, and when interpreted as a boolean, it must be true".
// (BIP62 rule 6)
// Note: CLEANSTACK should never be used without P2SH or WITNESS.
+ // Note: WITNESS_V0 and TAPSCRIPT script execution have behavior similar to CLEANSTACK as part of their
+ // consensus rules. It is automatic there and does not need this flag.
SCRIPT_VERIFY_CLEANSTACK = (1U << 8),
// Verify CHECKLOCKTIMEVERIFY
@@ -108,6 +110,8 @@ enum
// Segwit script only: Require the argument of OP_IF/NOTIF to be exactly 0x01 or empty vector
//
+ // Note: TAPSCRIPT script execution has behavior similar to MINIMALIF as part of its consensus
+ // rules. It is automatic there and does not depend on this flag.
SCRIPT_VERIFY_MINIMALIF = (1U << 13),
// Signature(s) must be empty vector if a CHECK(MULTI)SIG operation failed
@@ -122,13 +126,19 @@ enum
//
SCRIPT_VERIFY_CONST_SCRIPTCODE = (1U << 16),
- // Taproot validation (BIP 341)
+ // Taproot/Tapscript validation (BIPs 341 & 342)
//
SCRIPT_VERIFY_TAPROOT = (1U << 17),
// Making unknown Taproot leaf versions non-standard
//
SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_TAPROOT_VERSION = (1U << 18),
+
+ // Making unknown OP_SUCCESS non-standard
+ SCRIPT_VERIFY_DISCOURAGE_OP_SUCCESS = (1U << 19),
+
+ // Making unknown public key versions (in BIP 342 scripts) non-standard
+ SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE = (1U << 20),
};
bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror);
@@ -168,16 +178,32 @@ enum class SigVersion
BASE = 0, //!< Bare scripts and BIP16 P2SH-wrapped redeemscripts
WITNESS_V0 = 1, //!< Witness v0 (P2WPKH and P2WSH); see BIP 141
TAPROOT = 2, //!< Witness v1 with 32-byte program, not BIP16 P2SH-wrapped, key path spending; see BIP 341
+ TAPSCRIPT = 3, //!< Witness v1 with 32-byte program, not BIP16 P2SH-wrapped, script path spending, leaf version 0xc0; see BIP 342
};
struct ScriptExecutionData
{
+ //! Whether m_tapleaf_hash is initialized.
+ bool m_tapleaf_hash_init = false;
+ //! The tapleaf hash.
+ uint256 m_tapleaf_hash;
+
+ //! Whether m_codeseparator_pos is initialized.
+ bool m_codeseparator_pos_init = false;
+ //! Opcode position of the last executed OP_CODESEPARATOR (or 0xFFFFFFFF if none executed).
+ uint32_t m_codeseparator_pos;
+
//! Whether m_annex_present and (when needed) m_annex_hash are initialized.
bool m_annex_init = false;
//! Whether an annex is present.
bool m_annex_present;
//! Hash of the annex data.
uint256 m_annex_hash;
+
+ //! Whether m_validation_weight_left is initialized.
+ bool m_validation_weight_left_init = false;
+ //! How much validation weight is left (decremented for every successful non-empty signature check).
+ int64_t m_validation_weight_left;
};
/** Signature hash sizes */
@@ -186,6 +212,7 @@ static constexpr size_t WITNESS_V0_KEYHASH_SIZE = 20;
static constexpr size_t WITNESS_V1_TAPROOT_SIZE = 32;
static constexpr uint8_t TAPROOT_LEAF_MASK = 0xfe;
+static constexpr uint8_t TAPROOT_LEAF_TAPSCRIPT = 0xc0;
static constexpr size_t TAPROOT_CONTROL_BASE_SIZE = 33;
static constexpr size_t TAPROOT_CONTROL_NODE_SIZE = 32;
static constexpr size_t TAPROOT_CONTROL_MAX_NODE_COUNT = 128;