README
¶
txscript
Package txscript implements the bitcoin transaction script language. There is a comprehensive test suite.
This package has intentionally been designed so it can be used as a standalone package for any projects needing to use or validate bitcoin transaction scripts.
Bitcoin Scripts
Bitcoin provides a stack-based, FORTH-like language for the scripts in the bitcoin transactions. This language is not turing complete although it is still fairly powerful. A description of the language can be found at https://en.bitcoin.it/wiki/Script
Installation and Updating
$ go get -u github.com/cybriq/p9/txscript
Examples
-
Standard Pay-to-pubkey-hash Script
Demonstrates creating a script which pays to a bitcoin address. It also prints the created script hex and uses the DisasmString function to display the disassembled script. -
Extracting Details from Standard Scripts
Demonstrates extracting information from a standard public key script. -
Manually Signing a Transaction Output
Demonstrates manually creating and signing a redeem transaction.
License
Package txscript is licensed under the copyfree ISC License.
Documentation
¶
Overview ¶
Package txscript implements the bitcoin transaction script language.
A complete description of the script language used by bitcoin can be found at https://en.bitcoin.it/wiki/Script. The following only serves as a quick overview to provide information on how to use the package. This package provides data structures and functions to parse and execute bitcoin transaction scripts.
Script Overview ¶
Bitcoin transaction scripts are written in a stack-base, FORTH-like language. The bitcoin script language consists of a number of opcodes which fall into several categories such pushing and popping data to and from the stack, performing basic and bitwise arithmetic, conditional branching, comparing hashes, and checking cryptographic signatures. Scripts are processed from left to right and intentionally do not provide loops.
The vast majority of Bitcoin scripts at the time of this writing are of several standard forms which consist of a spender providing a public key and a signature which proves the spender owns the associated private key. This information is used to prove the the spender is authorized to perform the transaction. One benefit of using a scripting language is added flexibility in specifying what conditions must be met in order to spend bitcoins.
Errors ¶
Errors returned by this package are of type txscript.ScriptError. This allows the caller to programmatically determine the specific error by examining the ErrorCode field of the type asserted txscript.ScriptError while still providing rich error messages with contextual information. A convenience function named IsErrorCode is also provided to allow callers to easily check for a specific error code. See ErrorCode in the package documentation for a full list.
Index ¶
- Constants
- Variables
- func CalcMultiSigStats(script []byte) (int, int, error)
- func CalcSignatureHash(script []byte, hashType SigHashType, tx *wire.MsgTx, idx int) ([]byte, error)
- func CalcWitnessSigHash(script []byte, sigHashes *TxSigHashes, hType SigHashType, tx *wire.MsgTx, ...) ([]byte, error)
- func DisasmString(buf []byte) (string, error)
- func GetPreciseSigOpCount(scriptSig, scriptPubKey []byte, bip16 bool) int
- func GetSigOpCount(script []byte) int
- func IsErrorCode(e error, c ErrorCode) bool
- func IsPayToScriptHash(script []byte) bool
- func IsPayToWitnessPubKeyHash(script []byte) bool
- func IsPayToWitnessScriptHash(script []byte) bool
- func IsPushOnlyScript(script []byte) bool
- func IsUnspendable(pkScript []byte) bool
- func IsWitnessProgram(script []byte) bool
- func MultiSigScript(pubkeys []*btcaddr.PubKey, nrequired int) ([]byte, error)
- func NullDataScript(data []byte) ([]byte, error)
- func ParseScriptTemplate(script []byte, opcodes *[256]opcode) ([]parsedOpcode, error)
- func PayToAddrScript(addr btcaddr.Address) ([]byte, error)
- func PushedData(script []byte) ([][]byte, error)
- func RawTxInSignature(tx *wire.MsgTx, idx int, subScript []byte, hashType SigHashType, ...) ([]byte, error)
- func RawTxInWitnessSignature(tx *wire.MsgTx, sigHashes *TxSigHashes, idx int, amt int64, subScript []byte, ...) ([]byte, error)
- func SignTxOutput(chainParams *chaincfg.Params, tx *wire.MsgTx, idx int, pkScript []byte, ...) ([]byte, error)
- func SignatureScript(tx *wire.MsgTx, idx int, subscript []byte, hashType SigHashType, ...) ([]byte, error)
- func WitnessSignature(tx *wire.MsgTx, sigHashes *TxSigHashes, idx int, amt int64, subscript []byte, ...) (wire.TxWitness, error)
- type AtomicSwapDataPushes
- type Engine
- func (vm *Engine) CheckErrorCondition(finalScript bool) (e error)
- func (vm *Engine) DisasmPC() (string, error)
- func (vm *Engine) DisasmScript(idx int) (string, error)
- func (vm *Engine) Execute() (e error)
- func (vm *Engine) GetAltStack() [][]byte
- func (vm *Engine) GetStack() [][]byte
- func (vm *Engine) SetAltStack(data [][]byte)
- func (vm *Engine) SetStack(data [][]byte)
- func (vm *Engine) Step() (done bool, e error)
- type ErrScriptNotCanonical
- type ErrorCode
- type HashCache
- type KeyClosure
- type KeyDB
- type ScriptBuilder
- func (b *ScriptBuilder) AddData(data []byte) *ScriptBuilder
- func (b *ScriptBuilder) AddFullData(data []byte) *ScriptBuilder
- func (b *ScriptBuilder) AddInt64(val int64) *ScriptBuilder
- func (b *ScriptBuilder) AddOp(opcode byte) *ScriptBuilder
- func (b *ScriptBuilder) AddOps(opcodes []byte) *ScriptBuilder
- func (b *ScriptBuilder) Reset() *ScriptBuilder
- func (b *ScriptBuilder) Script() ([]byte, error)
- type ScriptClass
- type ScriptClosure
- type ScriptDB
- type ScriptError
- type ScriptFlags
- type ScriptInfo
- type SigCache
- type SigHashType
- type TxSigHashes
Constants ¶
const ( OP_0 = 0x00 // 0 OP_FALSE = 0x00 // 0 - AKA OP_0 OP_DATA_1 = 0x01 // 1 OP_DATA_2 = 0x02 // 2 OP_DATA_3 = 0x03 // 3 OP_DATA_4 = 0x04 // 4 OP_DATA_5 = 0x05 // 5 OP_DATA_6 = 0x06 // 6 OP_DATA_7 = 0x07 // 7 OP_DATA_8 = 0x08 // 8 OP_DATA_9 = 0x09 // 9 OP_DATA_10 = 0x0a // 10 OP_DATA_11 = 0x0b // 11 OP_DATA_12 = 0x0c // 12 OP_DATA_13 = 0x0d // 13 OP_DATA_14 = 0x0e // 14 OP_DATA_15 = 0x0f // 15 OP_DATA_16 = 0x10 // 16 OP_DATA_17 = 0x11 // 17 OP_DATA_18 = 0x12 // 18 OP_DATA_19 = 0x13 // 19 OP_DATA_20 = 0x14 // 20 OP_DATA_21 = 0x15 // 21 OP_DATA_22 = 0x16 // 22 OP_DATA_23 = 0x17 // 23 OP_DATA_24 = 0x18 // 24 OP_DATA_25 = 0x19 // 25 OP_DATA_26 = 0x1a // 26 OP_DATA_27 = 0x1b // 27 OP_DATA_28 = 0x1c // 28 OP_DATA_29 = 0x1d // 29 OP_DATA_30 = 0x1e // 30 OP_DATA_31 = 0x1f // 31 OP_DATA_32 = 0x20 // 32 OP_DATA_33 = 0x21 // 33 OP_DATA_34 = 0x22 // 34 OP_DATA_35 = 0x23 // 35 OP_DATA_36 = 0x24 // 36 OP_DATA_37 = 0x25 // 37 OP_DATA_38 = 0x26 // 38 OP_DATA_39 = 0x27 // 39 OP_DATA_40 = 0x28 // 40 OP_DATA_41 = 0x29 // 41 OP_DATA_42 = 0x2a // 42 OP_DATA_43 = 0x2b // 43 OP_DATA_44 = 0x2c // 44 OP_DATA_45 = 0x2d // 45 OP_DATA_46 = 0x2e // 46 OP_DATA_47 = 0x2f // 47 OP_DATA_48 = 0x30 // 48 OP_DATA_49 = 0x31 // 49 OP_DATA_50 = 0x32 // 50 OP_DATA_51 = 0x33 // 51 OP_DATA_52 = 0x34 // 52 OP_DATA_53 = 0x35 // 53 OP_DATA_54 = 0x36 // 54 OP_DATA_55 = 0x37 // 55 OP_DATA_56 = 0x38 // 56 OP_DATA_57 = 0x39 // 57 OP_DATA_58 = 0x3a // 58 OP_DATA_59 = 0x3b // 59 OP_DATA_60 = 0x3c // 60 OP_DATA_61 = 0x3d // 61 OP_DATA_62 = 0x3e // 62 OP_DATA_63 = 0x3f // 63 OP_DATA_64 = 0x40 // 64 OP_DATA_65 = 0x41 // 65 OP_DATA_66 = 0x42 // 66 OP_DATA_67 = 0x43 // 67 OP_DATA_68 = 0x44 // 68 OP_DATA_69 = 0x45 // 69 OP_DATA_70 = 0x46 // 70 OP_DATA_71 = 0x47 // 71 OP_DATA_72 = 0x48 // 72 OP_DATA_73 = 0x49 // 73 OP_DATA_74 = 0x4a // 74 OP_DATA_75 = 0x4b // 75 OP_PUSHDATA1 = 0x4c // 76 OP_PUSHDATA2 = 0x4d // 77 OP_PUSHDATA4 = 0x4e // 78 OP_1NEGATE = 0x4f // 79 OP_RESERVED = 0x50 // 80 OP_1 = 0x51 // 81 - AKA OP_TRUE OP_TRUE = 0x51 // 81 OP_2 = 0x52 // 82 OP_3 = 0x53 // 83 OP_4 = 0x54 // 84 OP_5 = 0x55 // 85 OP_6 = 0x56 // 86 OP_7 = 0x57 // 87 OP_8 = 0x58 // 88 OP_9 = 0x59 // 89 OP_10 = 0x5a // 90 OP_11 = 0x5b // 91 OP_12 = 0x5c // 92 OP_13 = 0x5d // 93 OP_14 = 0x5e // 94 OP_15 = 0x5f // 95 OP_16 = 0x60 // 96 OP_NOP = 0x61 // 97 OP_VER = 0x62 // 98 OP_IF = 0x63 // 99 OP_NOTIF = 0x64 // 100 OP_VERIF = 0x65 // 101 OP_VERNOTIF = 0x66 // 102 OP_ELSE = 0x67 // 103 OP_ENDIF = 0x68 // 104 OP_VERIFY = 0x69 // 105 OP_RETURN = 0x6a // 106 OP_TOALTSTACK = 0x6b // 107 OP_FROMALTSTACK = 0x6c // 108 OP_2DROP = 0x6d // 109 OP_2DUP = 0x6e // 110 OP_3DUP = 0x6f // 111 OP_2OVER = 0x70 // 112 OP_2ROT = 0x71 // 113 OP_2SWAP = 0x72 // 114 OP_IFDUP = 0x73 // 115 OP_DEPTH = 0x74 // 116 OP_DROP = 0x75 // 117 OP_DUP = 0x76 // 118 OP_NIP = 0x77 // 119 OP_OVER = 0x78 // 120 OP_PICK = 0x79 // 121 OP_ROLL = 0x7a // 122 OP_ROT = 0x7b // 123 OP_SWAP = 0x7c // 124 OP_TUCK = 0x7d // 125 OP_CAT = 0x7e // 126 OP_SUBSTR = 0x7f // 127 OP_LEFT = 0x80 // 128 OP_RIGHT = 0x81 // 129 OP_SIZE = 0x82 // 130 OP_INVERT = 0x83 // 131 OP_AND = 0x84 // 132 OP_OR = 0x85 // 133 OP_XOR = 0x86 // 134 OP_EQUAL = 0x87 // 135 OP_EQUALVERIFY = 0x88 // 136 OP_RESERVED1 = 0x89 // 137 OP_RESERVED2 = 0x8a // 138 OP_1ADD = 0x8b // 139 OP_1SUB = 0x8c // 140 OP_2MUL = 0x8d // 141 OP_2DIV = 0x8e // 142 OP_NEGATE = 0x8f // 143 OP_ABS = 0x90 // 144 OP_NOT = 0x91 // 145 OP_0NOTEQUAL = 0x92 // 146 OP_ADD = 0x93 // 147 OP_SUB = 0x94 // 148 OP_MUL = 0x95 // 149 OP_DIV = 0x96 // 150 OP_MOD = 0x97 // 151 OP_LSHIFT = 0x98 // 152 OP_RSHIFT = 0x99 // 153 OP_BOOLAND = 0x9a // 154 OP_BOOLOR = 0x9b // 155 OP_NUMEQUAL = 0x9c // 156 OP_NUMEQUALVERIFY = 0x9d // 157 OP_NUMNOTEQUAL = 0x9e // 158 OP_LESSTHAN = 0x9f // 159 OP_GREATERTHAN = 0xa0 // 160 OP_LESSTHANOREQUAL = 0xa1 // 161 OP_GREATERTHANOREQUAL = 0xa2 // 162 OP_MIN = 0xa3 // 163 OP_MAX = 0xa4 // 164 OP_WITHIN = 0xa5 // 165 OP_RIPEMD160 = 0xa6 // 166 OP_SHA1 = 0xa7 // 167 OP_SHA256 = 0xa8 // 168 OP_HASH160 = 0xa9 // 169 OP_HASH256 = 0xaa // 170 OP_CODESEPARATOR = 0xab // 171 OP_CHECKSIG = 0xac // 172 OP_CHECKSIGVERIFY = 0xad // 173 OP_CHECKMULTISIG = 0xae // 174 OP_CHECKMULTISIGVERIFY = 0xaf // 175 OP_NOP1 = 0xb0 // 176 OP_NOP2 = 0xb1 // 177 OP_CHECKLOCKTIMEVERIFY = 0xb1 // 177 - AKA OP_NOP2 OP_NOP3 = 0xb2 // 178 OP_CHECKSEQUENCEVERIFY = 0xb2 // 178 - AKA OP_NOP3 OP_NOP4 = 0xb3 // 179 OP_NOP5 = 0xb4 // 180 OP_NOP6 = 0xb5 // 181 OP_NOP7 = 0xb6 // 182 OP_NOP8 = 0xb7 // 183 OP_NOP9 = 0xb8 // 184 OP_NOP10 = 0xb9 // 185 OP_UNKNOWN186 = 0xba // 186 OP_UNKNOWN187 = 0xbb // 187 OP_UNKNOWN188 = 0xbc // 188 OP_UNKNOWN189 = 0xbd // 189 OP_UNKNOWN190 = 0xbe // 190 OP_UNKNOWN191 = 0xbf // 191 OP_UNKNOWN192 = 0xc0 // 192 OP_UNKNOWN193 = 0xc1 // 193 OP_UNKNOWN194 = 0xc2 // 194 OP_UNKNOWN195 = 0xc3 // 195 OP_UNKNOWN196 = 0xc4 // 196 OP_UNKNOWN197 = 0xc5 // 197 OP_UNKNOWN198 = 0xc6 // 198 OP_UNKNOWN199 = 0xc7 // 199 OP_UNKNOWN200 = 0xc8 // 200 OP_UNKNOWN201 = 0xc9 // 201 OP_UNKNOWN202 = 0xca // 202 OP_UNKNOWN203 = 0xcb // 203 OP_UNKNOWN204 = 0xcc // 204 OP_UNKNOWN205 = 0xcd // 205 OP_UNKNOWN206 = 0xce // 206 OP_UNKNOWN207 = 0xcf // 207 OP_UNKNOWN208 = 0xd0 // 208 OP_UNKNOWN209 = 0xd1 // 209 OP_UNKNOWN210 = 0xd2 // 210 OP_UNKNOWN211 = 0xd3 // 211 OP_UNKNOWN212 = 0xd4 // 212 OP_UNKNOWN213 = 0xd5 // 213 OP_UNKNOWN214 = 0xd6 // 214 OP_UNKNOWN215 = 0xd7 // 215 OP_UNKNOWN216 = 0xd8 // 216 OP_UNKNOWN217 = 0xd9 // 217 OP_UNKNOWN218 = 0xda // 218 OP_UNKNOWN219 = 0xdb // 219 OP_UNKNOWN220 = 0xdc // 220 OP_UNKNOWN221 = 0xdd // 221 OP_UNKNOWN222 = 0xde // 222 OP_UNKNOWN223 = 0xdf // 223 OP_UNKNOWN224 = 0xe0 // 224 OP_UNKNOWN225 = 0xe1 // 225 OP_UNKNOWN226 = 0xe2 // 226 OP_UNKNOWN227 = 0xe3 // 227 OP_UNKNOWN228 = 0xe4 // 228 OP_UNKNOWN229 = 0xe5 // 229 OP_UNKNOWN230 = 0xe6 // 230 OP_UNKNOWN231 = 0xe7 // 231 OP_UNKNOWN232 = 0xe8 // 232 OP_UNKNOWN233 = 0xe9 // 233 OP_UNKNOWN234 = 0xea // 234 OP_UNKNOWN235 = 0xeb // 235 OP_UNKNOWN236 = 0xec // 236 OP_UNKNOWN237 = 0xed // 237 OP_UNKNOWN238 = 0xee // 238 OP_UNKNOWN239 = 0xef // 239 OP_UNKNOWN240 = 0xf0 // 240 OP_UNKNOWN241 = 0xf1 // 241 OP_UNKNOWN242 = 0xf2 // 242 OP_UNKNOWN243 = 0xf3 // 243 OP_UNKNOWN244 = 0xf4 // 244 OP_UNKNOWN245 = 0xf5 // 245 OP_UNKNOWN246 = 0xf6 // 246 OP_UNKNOWN247 = 0xf7 // 247 OP_UNKNOWN248 = 0xf8 // 248 OP_UNKNOWN249 = 0xf9 // 249 OP_SMALLINTEGER = 0xfa // 250 - bitcoin core internal OP_PUBKEYS = 0xfb // 251 - bitcoin core internal OP_UNKNOWN252 = 0xfc // 252 OP_PUBKEYHASH = 0xfd // 253 - bitcoin core internal OP_PUBKEY = 0xfe // 254 - bitcoin core internal OP_INVALIDOPCODE = 0xff // 255 - bitcoin core internal )
const ( OpCondFalse = 0 OpCondTrue = 1 OpCondSkip = 2 )
const ( SigHashOld SigHashType = 0x0 SigHashAll SigHashType = 0x1 SigHashNone SigHashType = 0x2 SigHashSingle SigHashType = 0x3 SigHashAnyOneCanPay SigHashType = 0x80 MaxOpsPerScript = 201 // Max number of non-push operations. MaxPubKeysPerMultiSig = 20 // Multisig can't have more sigs than this. MaxScriptElementSize = 520 // Max bytes pushable to the stack. )
const ( // LockTimeThreshold is the number below which a lock time is interpreted to be a block number. Since an average of // one block is generated per 10 minutes, this allows blocks for about 9,512 years. LockTimeThreshold = 5e8 // Tue Nov 5 00:53:20 1985 UTC )
Variables ¶
var Bip16Activation = time.Unix(1333238400, 0)
Bip16Activation is the timestamp where BIP0016 is valid to use in the blockchain. To be used to determine if BIP0016 should be called for or not. This timestamp corresponds to Sun Apr 1 00:00:00 UTC 2012.
var F, E, W, I, D, T log.LevelPrinter = log.GetLogPrinterSet(subsystem)
var OpcodeArray = [256]opcode{}/* 256 elements not displayed */
OpcodeArray holds details about all possible opcodes such as how many bytes the opcode and any associated data should take, its human-readable name, and the handler function.
var OpcodeByName = make(map[string]byte)
OpcodeByName is a map that can be used to lookup an opcode by its human-readable name (OP_CHECKMULTISIG, OP_CHECKSIG, etc).
Functions ¶
func CalcMultiSigStats ¶
CalcMultiSigStats returns the number of public keys and signatures from a multi-signature transaction script. The passed script MUST already be known to be a multi-signature script.
func CalcSignatureHash ¶
func CalcSignatureHash( script []byte, hashType SigHashType, tx *wire.MsgTx, idx int, ) ([]byte, error)
CalcSignatureHash will given a script and hash type for the current script engine instance calculate the signature hash to be used for signing and verification.
func CalcWitnessSigHash ¶
func CalcWitnessSigHash( script []byte, sigHashes *TxSigHashes, hType SigHashType, tx *wire.MsgTx, idx int, amt int64, ) ([]byte, error)
CalcWitnessSigHash computes the sighash digest for the specified input of the target transaction observing the desired sig hash type.
func DisasmString ¶
DisasmString formats a disassembled script for one line printing. When the script fails to parse, the returned string will contain the disassembled script up to the point the failure occurred along with the string '[error]' appended. In addition, the reason the script failed to parse is returned if the caller wants more information about the failure.
func GetPreciseSigOpCount ¶
GetPreciseSigOpCount returns the number of signature operations in scriptPubKey. If bip16 is true then scriptSig may be searched for the Pay -To-Script-Hash script in order to find the precise number of signature operations in the transaction. If the script fails to parse, then the count up to the point of failure is returned.
func GetSigOpCount ¶
GetSigOpCount provides a quick count of the number of signature operations in a script. a CHECKSIG operations counts for 1, and a CHECK_MULTISIG for 20. If the script fails to parse, then the count up to the point of failure is returned.
func IsErrorCode ¶
IsErrorCode returns whether or not the provided error is a script error with the provided error code.
func IsPayToScriptHash ¶
IsPayToScriptHash returns true if the script is in the standard pay -to-script-hash (P2SH) format, false otherwise.
func IsPayToWitnessPubKeyHash ¶
IsPayToWitnessPubKeyHash returns true if the is in the standard pay -to-witness-pubkey-hash (P2WKH) format, false otherwise.
func IsPayToWitnessScriptHash ¶
IsPayToWitnessScriptHash returns true if the is in the standard pay -to-witness-script-hash (P2WSH) format, false otherwise.
func IsPushOnlyScript ¶
func IsUnspendable ¶
IsUnspendable returns whether the passed public key script is unspendable, or guaranteed to fail at execution. This allows inputs to be pruned instantly when entering the UTXO set.
func IsWitnessProgram ¶
IsWitnessProgram returns true if the passed script is a valid witness program which is encoded according to the passed witness program version. A witness program must be a small integer (from 0-16), followed by 2-40 bytes of pushed data.
func MultiSigScript ¶
MultiSigScript returns a valid script for a multisignature redemption where nrequired of the keys in pubkeys are required to have signed the transaction for success. An ScriptError with the error code errTooManyRequiredSigs will be returned if nrequired is larger than the number of keys provided.
func NullDataScript ¶
NullDataScript creates a provably-prunable script containing OP_RETURN followed by the passed data. An ScriptError with the error code errTooMuchNullData will be returned if the length of the passed data exceeds MaxDataCarrierSize.
func ParseScriptTemplate ¶
ParseScriptTemplate is the same as parseScript but allows the passing of the template list for testing purposes. When there are parse errors, it returns the list of parsed opcodes up to the point of failure along with the error.
func PayToAddrScript ¶
PayToAddrScript creates a new script to pay a transaction output to a the specified address.
func PushedData ¶
PushedData returns an array of byte slices containing any pushed data found in the passed script. This includes OP_0, but not OP_1 - OP_16.
func RawTxInSignature ¶
func RawTxInSignature( tx *wire.MsgTx, idx int, subScript []byte, hashType SigHashType, key *ecc.PrivateKey, ) ([]byte, error)
RawTxInSignature returns the serialized ECDSA signature for the input idx of the given transaction, with hashType appended to it.
func RawTxInWitnessSignature ¶
func RawTxInWitnessSignature( tx *wire.MsgTx, sigHashes *TxSigHashes, idx int, amt int64, subScript []byte, hashType SigHashType, key *ecc.PrivateKey, ) ([]byte, error)
RawTxInWitnessSignature returns the serialized ECDSA signature for the input idx of the given transaction, with the hashType appended to it. This function is identical to RawTxInSignature, however the signature generated signs a new sighash digest defined in BIP0143.
func SignTxOutput ¶
func SignTxOutput( chainParams *chaincfg.Params, tx *wire.MsgTx, idx int, pkScript []byte, hashType SigHashType, kdb KeyDB, sdb ScriptDB, previousScript []byte, ) ([]byte, error)
SignTxOutput signs output idx of the given tx to resolve the script given in pkScript with a signature type of hashType. Any keys required will be looked up by calling getKey() with the string of the given address. Any pay-to-script-hash signatures will be similarly looked up by calling getScript. If previousScript is provided then the results in previousScript will be merged in a type-dependent manner with the newly generated signature script.
func SignatureScript ¶
func SignatureScript( tx *wire.MsgTx, idx int, subscript []byte, hashType SigHashType, privKey *ecc.PrivateKey, compress bool, ) ([]byte, error)
SignatureScript creates an input signature script for tx to spend DUO sent from a previous output to the owner of privKey. tx must include all transaction inputs and outputs, however txin scripts are allowed to be filled or empty. The returned script is calculated to be used as the idx'th txin sigscript for tx. subscript is the PkScript of the previous output being used as the idx'th input. privKey is serialized in either a compressed or uncompressed format based on compress. This format must match the same format used to generate the payment address, or the script validation will fail.
func WitnessSignature ¶
func WitnessSignature( tx *wire.MsgTx, sigHashes *TxSigHashes, idx int, amt int64, subscript []byte, hashType SigHashType, privKey *ecc.PrivateKey, compress bool, ) (wire.TxWitness, error)
WitnessSignature creates an input witness stack for tx to spend DUO sent from a previous output to the owner of privKey using the p2wkh script template. The passed transaction must contain all the inputs and outputs as dictated by the passed hashType. The signature generated observes the new transaction digest algorithm defined within BIP0143.
Types ¶
type AtomicSwapDataPushes ¶
type AtomicSwapDataPushes struct {
RecipientHash160 [20]byte
RefundHash160 [20]byte
SecretHash [32]byte
SecretSize int64
LockTime int64
}
AtomicSwapDataPushes houses the data pushes found in atomic swap contracts.
func ExtractAtomicSwapDataPushes ¶
func ExtractAtomicSwapDataPushes( version uint16, pkScript []byte, ) (*AtomicSwapDataPushes, error)
ExtractAtomicSwapDataPushes returns the data pushes from an atomic swap contract. If the script is not an atomic swap contract,
ExtractAtomicSwapDataPushes returns (nil, nil). Non-nil errors are returned for unparsable scripts. NOTE: Atomic swaps are not considered standard script types by the dcrd mempool policy and should be used with P2SH. The atomic swap format is also expected to change to use a more secure hash function in the future. This function is only defined in the txscript package due to API limitations which prevent callers using txscript to parse nonstandard scripts.
type Engine ¶
type Engine struct {
// contains filtered or unexported fields
}
Engine is the virtual machine that executes scripts.
func NewEngine ¶
func NewEngine( scriptPubKey []byte, tx *wire.MsgTx, txIdx int, flags ScriptFlags, sigCache *SigCache, hashCache *TxSigHashes, inputAmount int64, ) (*Engine, error)
NewEngine returns a new script engine for the provided public key script, transaction, and input index. The flags modify the behavior of the script engine according to the description provided by each flag.
func (*Engine) CheckErrorCondition ¶
CheckErrorCondition returns nil if the running script has ended and was successful, leaving a a true boolean on the stack. An error otherwise, including if the script has not finished.
func (*Engine) DisasmPC ¶
DisasmPC returns the string for the disassembly of the opcode that will be next to execute when Step() is called.
func (*Engine) DisasmScript ¶
DisasmScript returns the disassembly string for the script at the requested offset index. Index 0 is the signature script and 1 is the public key script.
func (*Engine) Execute ¶
Execute will execute all scripts in the script engine and return either nil for successful validation or an error if one occurred.
func (*Engine) GetAltStack ¶
GetAltStack returns the contents of the alternate stack as an array where the last item in the array is the top of the stack.
func (*Engine) GetStack ¶
GetStack returns the contents of the primary stack as an array. where the last item in the array is the top of the stack.
func (*Engine) SetAltStack ¶
SetAltStack sets the contents of the alternate stack to the contents of the provided array where the last item in the array will be the top of the stack.
func (*Engine) SetStack ¶
SetStack sets the contents of the primary stack to the contents of the provided array where the last item in the array will be the top of the stack.
func (*Engine) Step ¶
Step will execute the next instruction and move the program counter to the next opcode in the script, or the next script if the current has ended. Step will return true in the case that the last opcode was successfully executed. The result of calling Step or any other method is undefined if an error is returned.
type ErrScriptNotCanonical ¶
type ErrScriptNotCanonical string
ErrScriptNotCanonical identifies a non-canonical script. The caller can use a type assertion to detect this error type.
func (ErrScriptNotCanonical) Error ¶
func (e ErrScriptNotCanonical) Error() string
ScriptError implements the error interface.
type ErrorCode ¶
type ErrorCode int
ErrorCode identifies a kind of script error.
const ( // ErrInternal is returned if internal consistency checks fail. In practice // this error should never be seen as it would mean there is an error in the // engine logic. ErrInternal ErrorCode = iota // ErrInvalidFlags is returned when the passed flags to NewEngine contain an // invalid combination. ErrInvalidFlags // ErrInvalidIndex is returned when an out-of-bounds index is passed to a // function. ErrInvalidIndex // ErrUnsupportedAddress is returned when a concrete type that implements a // util.Address is not a supported type. ErrUnsupportedAddress // ErrNotMultisigScript is returned from CalcMultiSigStats when the provided // script is not a multisig script. ErrNotMultisigScript // ErrTooManyRequiredSigs is returned from MultiSigScript when the specified // number of required signatures is larger than the number of provided public // keys. ErrTooManyRequiredSigs // ErrTooMuchNullData is returned from NullDataScript when the length of the // provided data exceeds MaxDataCarrierSize. ErrTooMuchNullData // ErrEarlyReturn is returned when OP_RETURN is executed in the script. ErrEarlyReturn // ErrEmptyStack is returned when the script evaluated without error, but // terminated with an empty top stack element. ErrEmptyStack // ErrEvalFalse is returned when the script evaluated without error but // terminated with a false top stack element. ErrEvalFalse // ErrScriptUnfinished is returned when CheckErrorCondition is called on a // script that has not finished executing. ErrScriptUnfinished // ErrInvalidProgramCounter is... ErrInvalidProgramCounter // ErrScriptTooBig is returned if a script is larger than MaxScriptSize. ErrScriptTooBig // ErrElementTooBig is returned if the size of an element to be pushed to the // stack is over MaxScriptElementSize. ErrElementTooBig // ErrTooManyOperations is returned if a script has more than MaxOpsPerScript // opcodes that do not push data. ErrTooManyOperations // ErrStackOverflow is returned when stack and altstack combined depth is // over the limit. ErrStackOverflow // ErrInvalidPubKeyCount is returned when the number of public keys specified // for a multsig is either negative or greater than MaxPubKeysPerMultiSig. ErrInvalidPubKeyCount // ErrInvalidSignatureCount is returned when the number of signatures // specified for a multisig is either negative or greater than the number of // public keys. ErrInvalidSignatureCount // ErrNumberTooBig is returned when the argument for an opcode that expects // numeric input is larger than the expected maximum number of bytes. For the // most part, opcodes that deal with stack manipulation via offsets, // arithmetic, numeric comparison, and boolean logic are those that this // applies to. However, any opcode that expects numeric input may fail with // this code. ErrNumberTooBig // ErrVerify is returned when OP_VERIFY is encountered in a script and // the top item on the data stack does not evaluate to true. ErrVerify // ErrEqualVerify is returned when OP_EQUALVERIFY is encountered in a script // and the top item on the data stack does not evaluate to true. ErrEqualVerify // ErrNumEqualVerify is returned when OP_NUMEQUALVERIFY is encountered in a // script and the top item on the data stack does not evaluate to true. ErrNumEqualVerify // ErrCheckSigVerify is returned when OP_CHECKSIGVERIFY is encountered in a // script and the top item on the data stack does not evaluate to true. ErrCheckSigVerify // ErrCheckMultiSigVerify is returned when OP_CHECKMULTISIGVERIFY is // encountered in a script and the top item on the data stack does not // evaluate to true. ErrCheckMultiSigVerify // ErrDisabledOpcode is returned when a disabled opcode is encountered in a // script. ErrDisabledOpcode // ErrReservedOpcode is returned when an opcode marked as reserved is // encountered in a script. ErrReservedOpcode // ErrMalformedPush is returned when a data push opcode tries to push more // bytes than are left in the script. ErrMalformedPush // ErrInvalidStackOperation is returned when a stack operation is attempted // with a number that is invalid for the current stack size. ErrInvalidStackOperation // ErrUnbalancedConditional is returned when an OP_ELSE or OP_ENDIF is // encountered in a script without first having an OP_IF or OP_NOTIF or the // end of script is reached without encountering an OP_ENDIF when an OP_IF or // OP_NOTIF was previously encountered. ErrUnbalancedConditional // ErrMinimalData is returned when the ScriptVerifyMinimalData flag is set // and the script contains push operations that do not use the minimal opcode // required. ErrMinimalData // ErrInvalidSigHashType is returned when a signature hash type is not one of // the supported types. ErrInvalidSigHashType // ErrSigTooShort is returned when a signature that should be a // canonically-encoded DER signature is too short. ErrSigTooShort // ErrSigTooLong is returned when a signature that should be a // canonically-encoded DER signature is too long. ErrSigTooLong // ErrSigInvalidSeqID is returned when a signature that should be a // canonically-encoded DER signature does not have the expected ASN.1 // sequence ID. ErrSigInvalidSeqID // ErrSigInvalidDataLen is returned a signature that should be a // canonically-encoded DER signature does not specify the correct number of // remaining bytes for the R and S portions. ErrSigInvalidDataLen // ErrSigMissingSTypeID is returned a signature that should be a // canonically-encoded DER signature does not provide the ASN.1 type ID for // S. ErrSigMissingSTypeID // ErrSigMissingSLen is returned when a signature that should be a // canonically-encoded DER signature does not provide the length of S. ErrSigMissingSLen // ErrSigInvalidSLen is returned a signature that should be a // canonically-encoded DER signature does not specify the correct number of // bytes for the S portion. ErrSigInvalidSLen // ErrSigInvalidRIntID is returned when a signature that should be a // canonically-encoded DER signature does not have the expected ASN.1 integer // ID for R. ErrSigInvalidRIntID // ErrSigZeroRLen is returned when a signature that should be a // canonically-encoded DER signature has an R length of zero. ErrSigZeroRLen // ErrSigNegativeR is returned when a signature that should be a // canonically-encoded DER signature has a negative value for R. ErrSigNegativeR // ErrSigTooMuchRPadding is returned when a signature that should be a // canonically-encoded DER signature has too much padding for R. ErrSigTooMuchRPadding // ErrSigInvalidSIntID is returned when a signature that should be a // canonically-encoded DER signature does not have the expected ASN.1 integer // ID for S. ErrSigInvalidSIntID // ErrSigZeroSLen is returned when a signature that should be a // canonically-encoded DER signature has an S length of zero. ErrSigZeroSLen // ErrSigNegativeS is returned when a signature that should be a // canonically-encoded DER signature has a negative value for S. ErrSigNegativeS // ErrSigTooMuchSPadding is returned when a signature that should be a // canonically-encoded DER signature has too much padding for S. ErrSigTooMuchSPadding // ErrSigHighS is returned when the ScriptVerifyLowS flag is set and the // script contains any signatures whose S values are higher than the half // order. ErrSigHighS // ErrNotPushOnly is returned when a script that is required to only push // data to the stack performs other operations. A couple of cases where this // applies is for a pay-to-script-hash signature script when bip16 is active // and when the ScriptVerifySigPushOnly flag is set. ErrNotPushOnly // ErrSigNullDummy is returned when the ScriptStrictMultiSig flag is set and // a multisig script has anything other than 0 for the extra dummy argument. ErrSigNullDummy // ErrPubKeyType is returned when the ScriptVerifyStrictEncoding flag is set // and the script contains invalid public keys. ErrPubKeyType // ErrCleanStack is returned when the ScriptVerifyCleanStack flag is set, and // after evalution, the stack does not contain only a single element. ErrCleanStack // ErrNullFail is returned when the ScriptVerifyNullFail flag is set and // signatures are not empty on failed checksig or checkmultisig operations. ErrNullFail // ErrWitnessMalleated is returned if ScriptVerifyWitness is set and a native // p2wsh program is encountered which has a non-empty sigScript. ErrWitnessMalleated // ErrWitnessMalleatedP2SH is returned if ScriptVerifyWitness if set and the // validation logic for nested p2sh encounters a sigScript which isn't *exactyl* // a datapush of the witness program. ErrWitnessMalleatedP2SH // ErrDiscourageUpgradableNOPs is returned when the // ScriptDiscourageUpgradableNops flag is set and a NOP opcode is encountered // in a script. ErrDiscourageUpgradableNOPs // ErrNegativeLockTime is returned when a script contains an opcode that // interprets a negative lock time. ErrNegativeLockTime // ErrUnsatisfiedLockTime is returned when a script contains an opcode that // involves a lock time and the required lock time has not been reached. ErrUnsatisfiedLockTime // ErrMinimalIf is returned if ScriptVerifyWitness is set and the operand of an // OP_IF/OP_NOF_IF are not either an empty vector or [0x01]. ErrMinimalIf // ErrDiscourageUpgradableWitnessProgram is returned if ScriptVerifyWitness is // set and the versino of an executing witness program is outside the set of // currently defined witness program vesions. ErrDiscourageUpgradableWitnessProgram // ErrWitnessProgramEmpty is returned if ScriptVerifyWitness is set and the // witness stack itself is empty. ErrWitnessProgramEmpty // ErrWitnessProgramMismatch is returned if ScriptVerifyWitness is set and the // witness itself for a p2wkh witness program isn't *exactly* 2 items or if the // witness for a p2wsh isn't the sha255 of the witness script. ErrWitnessProgramMismatch // ErrWitnessProgramWrongLength is returned if ScriptVerifyWitness is set and // the length of the witness program violates the length as dictated by the // current witness version. ErrWitnessProgramWrongLength // ErrWitnessUnexpected is returned if ScriptVerifyWitness is set and a // transaction includes witness data but doesn't spend an which is a witness // program (nested or native). ErrWitnessUnexpected // ErrWitnessPubKeyType is returned if ScriptVerifyWitness is set and the public // key used in either a check-sig or check-multi-sig isn't serialized in a // compressed format. ErrWitnessPubKeyType )
These constants are used to identify a specific ScriptError.
type HashCache ¶
HashCache houses a set of partial sighashes keyed by txid. The set of partial sighashes are those introduced within BIP0143 by the new more efficient sighash digest calculation algorithm. Using this threadsafe shared cache, multiple goroutines can safely re-use the pre-computed partial sighashes speeding up validation time amongst all inputs found within a block.
func NewHashCache ¶
NewHashCache returns a new instance of the HashCache given a maximum number of entries which may exist within it at anytime.
func (*HashCache) AddSigHashes ¶
AddSigHashes computes, then adds the partial sighashes for the passed transaction.
func (*HashCache) ContainsHashes ¶
ContainsHashes returns true if the partial sighashes for the passed transaction currently exist within the HashCache, and false otherwise.
func (*HashCache) GetSigHashes ¶
func (h *HashCache) GetSigHashes(txid *chainhash.Hash) (*TxSigHashes, bool)
GetSigHashes possibly returns the previously cached partial sighashes for the passed transaction. This function also returns an additional boolean value indicating if the sighashes for the passed transaction were found to be present within the HashCache.
func (*HashCache) PurgeSigHashes ¶
PurgeSigHashes removes all partial sighashes from the HashCache belonging to the passed transaction.
type KeyClosure ¶
KeyClosure implements KeyDB with a closure.
func (KeyClosure) GetKey ¶
func (kc KeyClosure) GetKey(address btcaddr.Address) ( *ecc.PrivateKey, bool, error, )
GetKey implements KeyDB by returning the result of calling the closure.
type KeyDB ¶
KeyDB is an interface type provided to SignTxOutput, it encapsulates any user state required to get the private keys for an address.
type ScriptBuilder ¶
type ScriptBuilder struct {
// contains filtered or unexported fields
}
ScriptBuilder provides a facility for building custom scripts. It allows you to push opcodes, ints, and data while respecting canonical encoding. In general it does not ensure the script will execute correctly, however any data pushes which would exceed the maximum allowed script engine limits and are therefore guaranteed not to execute will not be pushed and will result in the Script function returning an error. For example, the following would build a 2-of-3 multisig script for usage in a pay-to-script-hash (although in this situation MultiSigScript() would be a better choice to generate the script):
builder := txscript.NewScriptBuilder()
builder.AddOp(txscript.OP_2).AddData(pubKey1).AddData(pubKey2)
builder.AddData(pubKey3).AddOp(txscript.OP_3)
builder.AddOp(txscript.OP_CHECKMULTISIG)
script, e := builder.Script()
if e != nil {
L.Script// // Handle the error.
return
}
log.Printf("Final multi-sig script: %x\n", script)
func NewScriptBuilder ¶
func NewScriptBuilder() *ScriptBuilder
NewScriptBuilder returns a new instance of a script builder. See ScriptBuilder for details.
func (*ScriptBuilder) AddData ¶
func (b *ScriptBuilder) AddData(data []byte) *ScriptBuilder
AddData pushes the passed data to the end of the script. It automatically chooses canonical opcodes depending on the length of the data. A zero length buffer will lead to a push of empty data onto the stack (OP_0) and any push of data greater than MaxScriptElementSize will not modify the script since that is not allowed by the script engine. Also, the script will not be modified if pushing the data would cause the script to exceed the maximum allowed script engine size.
func (*ScriptBuilder) AddFullData ¶
func (b *ScriptBuilder) AddFullData(data []byte) *ScriptBuilder
AddFullData should not typically be used by ordinary users as it does not include the checks which prevent data pushes larger than the maximum allowed txsizes which leads to scripts that can't be executed. This is provided for testing purposes such as regression tests where txsizes are intentionally made larger than allowed. Use AddData instead.
func (*ScriptBuilder) AddInt64 ¶
func (b *ScriptBuilder) AddInt64(val int64) *ScriptBuilder
AddInt64 pushes the passed integer to the end of the script. The script will not be modified if pushing the data would cause the script to exceed the maximum allowed script engine size.
func (*ScriptBuilder) AddOp ¶
func (b *ScriptBuilder) AddOp(opcode byte) *ScriptBuilder
AddOp pushes the passed opcode to the end of the script. The script will not be modified if pushing the opcode would cause the script to exceed the maximum allowed script engine size.
func (*ScriptBuilder) AddOps ¶
func (b *ScriptBuilder) AddOps(opcodes []byte) *ScriptBuilder
AddOps pushes the passed opcodes to the end of the script. The script will not be modified if pushing the opcodes would cause the script to exceed the maximum allowed script engine size.
func (*ScriptBuilder) Reset ¶
func (b *ScriptBuilder) Reset() *ScriptBuilder
Reset resets the script so it has no content.
func (*ScriptBuilder) Script ¶
func (b *ScriptBuilder) Script() ([]byte, error)
Script returns the currently built script. When any errors occurred while building the script, the script will be returned up the point of the first error along with the error.
type ScriptClass ¶
type ScriptClass byte
ScriptClass is an enumeration for the list of standard types of script.
const ( // MaxDataCarrierSize is the maximum number of bytes allowed in pushed data to // be considered a nulldata transaction MaxDataCarrierSize = 80 // StandardVerifyFlags are the script flags which are used when executing // transaction scripts to enforce additional checks which are required for the // script to be considered standard. These checks help reduce issues related to // transaction malleability as well as allow pay-to-script hash transactions. // Note these flags are different than what is required for the consensus rules // in that they are more strict. // TODO: This definition does not belong here. It belongs in a policy package. StandardVerifyFlags = ScriptBip16 | ScriptVerifyDERSignatures | ScriptVerifyStrictEncoding | ScriptVerifyMinimalData | ScriptStrictMultiSig | ScriptDiscourageUpgradableNops | ScriptVerifyCleanStack | ScriptVerifyNullFail | ScriptVerifyCheckLockTimeVerify | ScriptVerifyLowS | ScriptStrictMultiSig | ScriptVerifyMinimalIf NonStandardTy ScriptClass = iota // None of the recognized forms. PubKeyTy // Pay pubkey. PubKeyHashTy // Pay pubkey hash. // WitnessV0PubKeyHashTy // Pay witness pubkey hash. ScriptHashTy // Pay to script hash. // WitnessV0ScriptHashTy // Pay to witness script hash. MultiSigTy // Multi signature. NullDataTy // Empty data-only (provably prunable). )
A bunch of constants
func ExtractPkScriptAddrs ¶
func ExtractPkScriptAddrs( pkScript []byte, chainParams *chaincfg.Params, ) (ScriptClass, []btcaddr.Address, int, error)
ExtractPkScriptAddrs returns the type of script, addresses and required signatures associated with the passed PkScript. Note that it only works for 'standard' transaction script types. Any data such as public keys which are invalid are omitted from the results.
func GetScriptClass ¶
func GetScriptClass(script []byte) ScriptClass
GetScriptClass returns the class of the script passed. NonStandardTy will be returned when the script does not parse.
func (ScriptClass) String ¶
func (t ScriptClass) String() string
String implements the Stringer interface by returning the name of the enum script class. If the enum is invalid then "Invalid" will be returned.
type ScriptClosure ¶
ScriptClosure implements ScriptDB with a closure.
type ScriptDB ¶
ScriptDB is an interface type provided to SignTxOutput, it encapsulates any user state required to get the scripts for an pay-to-script-hash address.
type ScriptError ¶
ScriptError identifies a script-related error. It is used to indicate three classes of errors:
1) Script execution failures due to violating one of the many requirements imposed by the script engine or evaluating to false 2) Improper API usage by callers 3) Internal consistency check failures
The caller can use type assertions on the returned errors to access the ErrorCode field to ascertain the specific reason for the error. As an additional convenience, the caller may make use of the IsErrorCode function to check for a specific error code.
func (ScriptError) Error ¶
func (e ScriptError) Error() string
ScriptError satisfies the error interface and prints human-readable errors.
type ScriptFlags ¶
type ScriptFlags uint32
ScriptFlags is a bitmask defining additional operations or tests that will be done when executing a script pair.
const ( // ScriptBip16 defines whether the bip16 threshold has passed and thus pay-to-script hash transactions will be fully // validated. ScriptBip16 ScriptFlags = 1 << iota // ScriptStrictMultiSig defines whether to verify the stack item used by CHECKMULTISIG is zero length. ScriptStrictMultiSig // ScriptDiscourageUpgradableNops defines whether to verify that NOP1 through NOP10 are reserved for future // soft-fork upgrades. This flag must not be used for consensus critical code nor applied to blocks as this flag is // only for stricter standard transaction checks. This flag is only applied when the above opcodes are executed. ScriptDiscourageUpgradableNops // ScriptVerifyCheckLockTimeVerify defines whether to verify that a transaction output is spendable based on the // locktime. This is BIP0065. ScriptVerifyCheckLockTimeVerify // ScriptVerifyCheckSequenceVerify defines whether to allow execution pathways of a script to be restricted based on // the age of the output being spent. This is BIP0112. ScriptVerifyCheckSequenceVerify // ScriptVerifyCleanStack defines that the stack must contain only one stack // element after evaluation and that the element must be true if interpreted as // a boolean. This is rule 6 of BIP0062. This flag should never be used without // the ScriptBip16 flag nor the ScriptVerifyWitness flag. ScriptVerifyCleanStack // ScriptVerifyDERSignatures defines that signatures are required to compily with the DER format. ScriptVerifyDERSignatures // ScriptVerifyLowS defines that signtures are required to comply with the DER format and whose S value is <= order // / 2. This is rule 5 of BIP0062. ScriptVerifyLowS // ScriptVerifyMinimalData defines that signatures must use the smallest push operator. This is both rules 3 and 4 // of BIP0062. ScriptVerifyMinimalData // ScriptVerifyNullFail defines that signatures must be empty if a CHECKSIG or CHECKMULTISIG operation fails. ScriptVerifyNullFail // ScriptVerifySigPushOnly defines that signature scripts must contain only pushed data. This is rule 2 of BIP0062. ScriptVerifySigPushOnly // ScriptVerifyStrictEncoding defines that signature scripts and public keys must follow the strict encoding // requirements. ScriptVerifyStrictEncoding // ScriptVerifyWitness defines whether or not to verify a transaction output // using a witness program template. ScriptVerifyWitness // ScriptVerifyDiscourageUpgradeableWitnessProgram makes witness program with // versions 2-16 non-standard. ScriptVerifyDiscourageUpgradeableWitnessProgram // ScriptVerifyMinimalIf makes a script with an OP_IF/OP_NOTIF whose operand is anything other than empty vector or // [0x01] non-standard. ScriptVerifyMinimalIf // ScriptVerifyWitnessPubKeyType makes a script within a check-sig operation // whose public key isn't serialized in a compressed format non-standard. ScriptVerifyWitnessPubKeyType // MaxStackSize is the maximum combined height of stack and alt stack during execution. MaxStackSize = 1000 // MaxScriptSize is the maximum allowed length of a raw script. MaxScriptSize = 10000 )
type ScriptInfo ¶
type ScriptInfo struct {
// PkScriptClass is the class of the public key script and is equivalent to
// calling GetScriptClass on it.
PkScriptClass ScriptClass
// NumInputs is the number of inputs provided by the public key script.
NumInputs int
// ExpectedInputs is the number of outputs required by the signature script and
// any pay-to-script-hash scripts. The number will be -1 if unknown.
ExpectedInputs int
// SigOps is the number of signature operations in the script pair.
SigOps int
}
ScriptInfo houses information about a script pair that is determined by CalcScriptInfo.
func CalcScriptInfo ¶
func CalcScriptInfo(sigScript, pkScript []byte, bip16 bool) ( si *ScriptInfo, e error, )
CalcScriptInfo returns a structure providing data about the provided script pair. It will error if the pair is in someway invalid such that they can not be analysed, i.e. if they do not parse or the pkScript is not a push-only script
type SigCache ¶
SigCache implements an ECDSA signature verification cache with a randomized entry eviction policy. Only valid signatures will be added to the cache. The benefits of SigCache are two fold. Firstly, usage of SigCache mitigates a DoS attack wherein an attack causes a victim's client to hang due to worst-case behavior triggered while processing attacker crafted invalid transactions. A detailed description of the mitigated DoS attack can be found here: https://bitslog.wordpress.com/2013/01/23/fixed-bitcoin-vulnerability-explanation-why-the-signature-cache-is-a-dos-protection/. Secondly, usage of the SigCache introduces a signature verification optimization which speeds up the validation of transactions within a block, if they've already been seen and verified within the mempool.
func NewSigCache ¶
NewSigCache creates and initializes a new instance of SigCache. Its sole parameter 'maxEntries' represents the maximum number of entries allowed to exist in the SigCache at any particular moment. Random entries are evicted make room for new entries that would cause the number of entries in the cache to exceed the max.
func (*SigCache) Add ¶
Add adds an entry for a signature over 'sigHash' under public key 'pubKey' to the signature cache. In the event that the SigCache is 'full', an existing entry is randomly chosen to be evicted in order to make space for the new entry. NOTE: This function is safe for concurrent access. Writers will block simultaneous readers until function execution has concluded.
func (*SigCache) Exists ¶
func (s *SigCache) Exists( sigHash chainhash.Hash, sig *ecc.Signature, pubKey *ecc.PublicKey, ) bool
Exists returns true if an existing entry of 'sig' over 'sigHash' for public key 'pubKey' is found within the SigCache. Otherwise, false is returned. NOTE: This function is safe for concurrent access. Readers won't be blocked unless there exists a writer, adding an entry to the SigCache.
type SigHashType ¶
type SigHashType uint32
type TxSigHashes ¶
type TxSigHashes struct {
HashPrevOuts chainhash.Hash
HashSequence chainhash.Hash
HashOutputs chainhash.Hash
}
TxSigHashes houses the partial set of sighashes introduced within BIP0143. This partial set of sighashes may be re-used within each input across a transaction when validating all inputs. As a result, validation complexity for SigHashAll can be reduced by a polynomial factor.
func NewTxSigHashes ¶
func NewTxSigHashes(tx *wire.MsgTx) *TxSigHashes
NewTxSigHashes computes, and returns the cached sighashes of the given transaction.
Source Files