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m Remove fromold, since the old page was entirely my work. |
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A transaction is valid if nothing in the combined script triggers failure and the top stack item is true (1). | A transaction is valid if nothing in the combined script triggers failure and the top stack item is true (1). | ||
Scripts are big-endian. (Is all data, also?) | |||
== Words == | == Words == | ||
This is a list of | This is a list of all Script words (commands/functions). Some are currently disabled for security reasons. | ||
True=1 and False=0. | True=1 and False=0. | ||
=== Constants === | |||
When talking about scripts, these value-pushing words are usually omitted. | |||
{| class="wikitable" | |||
|- | |||
!Word | |||
!Opcode | |||
!Input | |||
!Output | |||
!Description | |||
|- | |||
|OP_0, OP_FALSE | |||
|0 | |||
|Nothing. | |||
|0 | |||
|The number 0 is pushed onto the stack. | |||
|- | |||
|N/A | |||
|1-75 | |||
|(special) | |||
|data | |||
|The next ''opcode'' bytes is data to be pushed onto the stack | |||
|- | |||
|OP_PUSHDATA1 | |||
|76 | |||
|(special) | |||
|data | |||
|The next byte contains the number of bytes to be pushed onto the stack. | |||
|- | |||
|OP_PUSHDATA2 | |||
|77 | |||
|(special) | |||
|data | |||
|The next two bytes contain the number of bytes to be pushed onto the stack. | |||
|- | |||
|OP_PUSHDATA4 | |||
|78 | |||
|(special) | |||
|data | |||
|The next four bytes contain the number of bytes to be pushed onto the stack. | |||
|- | |||
|OP_1NEGATE | |||
|79 | |||
|Nothing. | |||
| -1 | |||
|The number -1 is pushed onto the stack. | |||
|- | |||
|OP_1, OP_TRUE | |||
|81 | |||
|Nothing. | |||
|1 | |||
|The number 1 is pushed onto the stack. | |||
|- | |||
|OP_2-OP_16 | |||
|82-96 | |||
|Nothing. | |||
|2-16 | |||
|The number in the word name (2-16) is pushed onto the stack. | |||
|} | |||
=== Flow control === | === Flow control === | ||
| Line 15: | Line 75: | ||
|- | |- | ||
!Word | !Word | ||
!Opcode | |||
!Input | !Input | ||
!Output | !Output | ||
| Line 20: | Line 81: | ||
|- | |- | ||
|OP_NOP | |OP_NOP | ||
|97 | |||
|Nothing | |Nothing | ||
|Nothing | |Nothing | ||
| Line 25: | Line 87: | ||
|- | |- | ||
|OP_IF | |OP_IF | ||
|<expression> if [statements] [else [statements]] endif | |99 | ||
| colspan="2"|<expression> if [statements] [else [statements]] endif | |||
|If the top stack value is 1, the statements are executed. The top stack value is removed. | |If the top stack value is 1, the statements are executed. The top stack value is removed. | ||
|- | |- | ||
|OP_NOTIF | |OP_NOTIF | ||
|<expression> if [statements] [else [statements]] endif | |100 | ||
| colspan="2"|<expression> if [statements] [else [statements]] endif | |||
|If the top stack value is 0, the statements are executed. The top stack value is removed. | |If the top stack value is 0, the statements are executed. The top stack value is removed. | ||
|- | |- | ||
|OP_ELSE | |OP_ELSE | ||
|<expression> if [statements] [else [statements]] endif | |103 | ||
| colspan="2"|<expression> if [statements] [else [statements]] endif | |||
|If the preceding OP_IF was not executed, these statements are. | |If the preceding OP_IF was not executed, these statements are. | ||
|- | |- | ||
|OP_ENDIF | |OP_ENDIF | ||
|<expression> if [statements] [else [statements]] endif | |104 | ||
| colspan="2"|<expression> if [statements] [else [statements]] endif | |||
|Ends an if/else block. | |Ends an if/else block. | ||
|- | |- | ||
|OP_VERIFY | |OP_VERIFY | ||
|105 | |||
|True / false | |True / false | ||
|Nothing / False | |Nothing / False | ||
| Line 50: | Line 113: | ||
|- | |- | ||
|OP_RETURN | |OP_RETURN | ||
|106 | |||
|Nothing | |Nothing | ||
|Nothing | |Nothing | ||
| Line 60: | Line 124: | ||
|- | |- | ||
!Word | !Word | ||
!Opcode | |||
!Input | !Input | ||
!Output | !Output | ||
| Line 65: | Line 130: | ||
|- | |- | ||
|OP_TOALTSTACK | |OP_TOALTSTACK | ||
|107 | |||
|x1 | |x1 | ||
|(alt)x1 | |(alt)x1 | ||
| Line 70: | Line 136: | ||
|- | |- | ||
|OP_FROMALTSTACK | |OP_FROMALTSTACK | ||
|108 | |||
|(alt)x1 | |(alt)x1 | ||
|x1 | |x1 | ||
| Line 75: | Line 142: | ||
|- | |- | ||
|OP_IFDUP | |OP_IFDUP | ||
|115 | |||
|x | |x | ||
|x / x x | |x / x x | ||
| Line 80: | Line 148: | ||
|- | |- | ||
|OP_DEPTH | |OP_DEPTH | ||
|116 | |||
|Nothing | |Nothing | ||
|<Stack size> | |<Stack size> | ||
| Line 85: | Line 154: | ||
|- | |- | ||
|OP_DROP | |OP_DROP | ||
|117 | |||
|x | |x | ||
|Nothing | |Nothing | ||
| Line 90: | Line 160: | ||
|- | |- | ||
|OP_DUP | |OP_DUP | ||
|118 | |||
|x | |x | ||
|x x | |x x | ||
| Line 95: | Line 166: | ||
|- | |- | ||
|OP_NIP | |OP_NIP | ||
|119 | |||
|x1 x2 | |x1 x2 | ||
|x2 | |x2 | ||
| Line 100: | Line 172: | ||
|- | |- | ||
|OP_OVER | |OP_OVER | ||
|120 | |||
|x1 x2 | |x1 x2 | ||
|x1 x2 x1 | |x1 x2 x1 | ||
| Line 105: | Line 178: | ||
|- | |- | ||
|OP_PICK | |OP_PICK | ||
|121 | |||
|xn ... x2 x1 x0 <n> | |xn ... x2 x1 x0 <n> | ||
|xn ... x2 x1 x0 xn | |xn ... x2 x1 x0 xn | ||
| Line 110: | Line 184: | ||
|- | |- | ||
|OP_ROLL | |OP_ROLL | ||
|122 | |||
|xn ... x2 x1 x0 <n> | |xn ... x2 x1 x0 <n> | ||
|... x2 x1 x0 xn | |... x2 x1 x0 xn | ||
| Line 115: | Line 190: | ||
|- | |- | ||
|OP_ROT | |OP_ROT | ||
|123 | |||
|x1 x2 x3 | |x1 x2 x3 | ||
|x2 x3 x1 | |x2 x3 x1 | ||
| Line 120: | Line 196: | ||
|- | |- | ||
|OP_SWAP | |OP_SWAP | ||
|124 | |||
|x1 x2 | |x1 x2 | ||
|x2 x1 | |x2 x1 | ||
| Line 125: | Line 202: | ||
|- | |- | ||
|OP_TUCK | |OP_TUCK | ||
|125 | |||
|x1 x2 | |x1 x2 | ||
|x2 x1 x2 | |x2 x1 x2 | ||
| Line 130: | Line 208: | ||
|- | |- | ||
|OP_2DROP | |OP_2DROP | ||
|109 | |||
|x1 x2 | |x1 x2 | ||
|Nothing | |Nothing | ||
| Line 135: | Line 214: | ||
|- | |- | ||
|OP_2DUP | |OP_2DUP | ||
|110 | |||
|x1 x2 | |x1 x2 | ||
|x1 x2 x1 x2 | |x1 x2 x1 x2 | ||
| Line 140: | Line 220: | ||
|- | |- | ||
|OP_3DUP | |OP_3DUP | ||
|111 | |||
|x1 x2 x3 | |x1 x2 x3 | ||
|x1 x2 x3 x1 x2 x3 | |x1 x2 x3 x1 x2 x3 | ||
| Line 145: | Line 226: | ||
|- | |- | ||
|OP_2OVER | |OP_2OVER | ||
|112 | |||
|x1 x2 x3 x4 | |x1 x2 x3 x4 | ||
|x1 x2 x3 x4 x1 x2 | |x1 x2 x3 x4 x1 x2 | ||
| Line 150: | Line 232: | ||
|- | |- | ||
|OP_2ROT | |OP_2ROT | ||
|113 | |||
|x1 x2 x3 x4 x5 x6 | |x1 x2 x3 x4 x5 x6 | ||
|x3 x4 x5 x6 x1 x2 | |x3 x4 x5 x6 x1 x2 | ||
| Line 155: | Line 238: | ||
|- | |- | ||
|OP_2SWAP | |OP_2SWAP | ||
|114 | |||
|x1 x2 x3 x4 | |x1 x2 x3 x4 | ||
|x3 x4 x1 x2 | |x3 x4 x1 x2 | ||
| Line 165: | Line 249: | ||
|- | |- | ||
!Word | !Word | ||
!Opcode | |||
!Input | !Input | ||
!Output | !Output | ||
| Line 170: | Line 255: | ||
|- | |- | ||
|OP_CAT | |OP_CAT | ||
|126 | |||
|x1 x2 | |x1 x2 | ||
|out | |out | ||
| Line 175: | Line 261: | ||
|- | |- | ||
|OP_SUBSTR | |OP_SUBSTR | ||
|127 | |||
|in begin size | |in begin size | ||
|out | |out | ||
| Line 180: | Line 267: | ||
|- | |- | ||
|OP_LEFT | |OP_LEFT | ||
|128 | |||
|in size | |in size | ||
|out | |out | ||
| Line 185: | Line 273: | ||
|- | |- | ||
|OP_RIGHT | |OP_RIGHT | ||
|129 | |||
|in size | |in size | ||
|out | |out | ||
| Line 190: | Line 279: | ||
|- | |- | ||
|OP_SIZE | |OP_SIZE | ||
|130 | |||
|in | |in | ||
|in size | |in size | ||
| Line 205: | Line 295: | ||
|- | |- | ||
|OP_INVERT | |OP_INVERT | ||
|131 | |||
|in | |in | ||
|out | |out | ||
| Line 210: | Line 301: | ||
|- | |- | ||
|OP_AND | |OP_AND | ||
|132 | |||
|x1 x2 | |x1 x2 | ||
|out | |out | ||
| Line 215: | Line 307: | ||
|- | |- | ||
|OP_OR | |OP_OR | ||
|133 | |||
|x1 x2 | |x1 x2 | ||
|out | |out | ||
| Line 220: | Line 313: | ||
|- | |- | ||
|OP_XOR | |OP_XOR | ||
|134 | |||
|x1 x2 | |x1 x2 | ||
|out | |out | ||
| Line 225: | Line 319: | ||
|- | |- | ||
|OP_EQUAL | |OP_EQUAL | ||
|135 | |||
|x1 x2 | |x1 x2 | ||
|True / false | |True / false | ||
| Line 230: | Line 325: | ||
|- | |- | ||
|OP_EQUALVERIFY | |OP_EQUALVERIFY | ||
|136 | |||
|x1 x2 | |x1 x2 | ||
|True / false | |True / false | ||
| Line 240: | Line 336: | ||
|- | |- | ||
!Word | !Word | ||
!Opcode | |||
!Input | !Input | ||
!Output | !Output | ||
| Line 245: | Line 342: | ||
|- | |- | ||
|OP_1ADD | |OP_1ADD | ||
|139 | |||
|in | |in | ||
|out | |out | ||
| Line 250: | Line 348: | ||
|- | |- | ||
|OP_1SUB | |OP_1SUB | ||
|140 | |||
|in | |in | ||
|out | |out | ||
| Line 255: | Line 354: | ||
|- | |- | ||
|OP_2MUL | |OP_2MUL | ||
|141 | |||
|in | |in | ||
|out | |out | ||
| Line 260: | Line 360: | ||
|- | |- | ||
|OP_2DIV | |OP_2DIV | ||
|142 | |||
|in | |in | ||
|out | |out | ||
| Line 265: | Line 366: | ||
|- | |- | ||
|OP_NEGATE | |OP_NEGATE | ||
|143 | |||
|in | |in | ||
|out | |out | ||
| Line 270: | Line 372: | ||
|- | |- | ||
|OP_ABS | |OP_ABS | ||
|144 | |||
|in | |in | ||
|out | |out | ||
| Line 275: | Line 378: | ||
|- | |- | ||
|OP_NOT | |OP_NOT | ||
|145 | |||
|in | |in | ||
|out | |out | ||
| Line 280: | Line 384: | ||
|- | |- | ||
|OP_0NOTEQUAL | |OP_0NOTEQUAL | ||
|146 | |||
|in | |in | ||
|out | |out | ||
| Line 285: | Line 390: | ||
|- | |- | ||
|OP_ADD | |OP_ADD | ||
|147 | |||
|a b | |a b | ||
|out | |out | ||
| Line 290: | Line 396: | ||
|- | |- | ||
|OP_SUB | |OP_SUB | ||
|148 | |||
|a b | |a b | ||
|out | |out | ||
| Line 295: | Line 402: | ||
|- | |- | ||
|OP_MUL | |OP_MUL | ||
|149 | |||
|a b | |a b | ||
|out | |out | ||
| Line 300: | Line 408: | ||
|- | |- | ||
|OP_DIV | |OP_DIV | ||
|150 | |||
|a b | |a b | ||
|out | |out | ||
| Line 305: | Line 414: | ||
|- | |- | ||
|OP_MOD | |OP_MOD | ||
|151 | |||
|a b | |a b | ||
|out | |out | ||
| Line 310: | Line 420: | ||
|- | |- | ||
|OP_LSHIFT | |OP_LSHIFT | ||
|152 | |||
|a b | |a b | ||
|out | |out | ||
| Line 315: | Line 426: | ||
|- | |- | ||
|OP_RSHIFT | |OP_RSHIFT | ||
|153 | |||
|a b | |a b | ||
|out | |out | ||
| Line 320: | Line 432: | ||
|- | |- | ||
|OP_BOOLAND | |OP_BOOLAND | ||
|154 | |||
|a b | |a b | ||
|out | |out | ||
| Line 325: | Line 438: | ||
|- | |- | ||
|OP_BOOLOR | |OP_BOOLOR | ||
|155 | |||
|a b | |a b | ||
|out | |out | ||
| Line 330: | Line 444: | ||
|- | |- | ||
|OP_NUMEQUAL | |OP_NUMEQUAL | ||
|156 | |||
|a b | |a b | ||
|out | |out | ||
| Line 335: | Line 450: | ||
|- | |- | ||
|OP_NUMEQUALVERIFY | |OP_NUMEQUALVERIFY | ||
|157 | |||
|a b | |a b | ||
|out | |out | ||
| Line 340: | Line 456: | ||
|- | |- | ||
|OP_NUMNOTEQUAL | |OP_NUMNOTEQUAL | ||
|158 | |||
|a b | |a b | ||
|out | |out | ||
| Line 345: | Line 462: | ||
|- | |- | ||
|OP_LESSTHAN | |OP_LESSTHAN | ||
|159 | |||
|a b | |a b | ||
|out | |out | ||
| Line 350: | Line 468: | ||
|- | |- | ||
|OP_GREATERTHAN | |OP_GREATERTHAN | ||
|160 | |||
|a b | |a b | ||
|out | |out | ||
| Line 355: | Line 474: | ||
|- | |- | ||
|OP_LESSTHANOREQUAL | |OP_LESSTHANOREQUAL | ||
|161 | |||
|a b | |a b | ||
|out | |out | ||
| Line 360: | Line 480: | ||
|- | |- | ||
|OP_GREATERTHANOREQUAL | |OP_GREATERTHANOREQUAL | ||
|162 | |||
|a b | |a b | ||
|out | |out | ||
| Line 365: | Line 486: | ||
|- | |- | ||
|OP_MIN | |OP_MIN | ||
|163 | |||
|a b | |a b | ||
|out | |out | ||
| Line 370: | Line 492: | ||
|- | |- | ||
|OP_MAX | |OP_MAX | ||
|164 | |||
|a b | |a b | ||
|out | |out | ||
| Line 375: | Line 498: | ||
|- | |- | ||
|OP_WITHIN | |OP_WITHIN | ||
|165 | |||
|x min max | |x min max | ||
|out | |out | ||
| Line 385: | Line 509: | ||
|- | |- | ||
!Word | !Word | ||
!Opcode | |||
!Input | !Input | ||
!Output | !Output | ||
| Line 390: | Line 515: | ||
|- | |- | ||
|OP_RIPEMD160 | |OP_RIPEMD160 | ||
|166 | |||
|in | |in | ||
|hash | |hash | ||
| Line 395: | Line 521: | ||
|- | |- | ||
|OP_SHA1 | |OP_SHA1 | ||
|167 | |||
|in | |in | ||
|hash | |hash | ||
| Line 400: | Line 527: | ||
|- | |- | ||
|OP_SHA256 | |OP_SHA256 | ||
|168 | |||
|in | |in | ||
|hash | |hash | ||
| Line 405: | Line 533: | ||
|- | |- | ||
|OP_HASH160 | |OP_HASH160 | ||
|169 | |||
|in | |in | ||
|hash | |hash | ||
| Line 410: | Line 539: | ||
|- | |- | ||
|OP_HASH256 | |OP_HASH256 | ||
|170 | |||
|in | |in | ||
|hash | |hash | ||
| Line 415: | Line 545: | ||
|- | |- | ||
|OP_CODESEPARATOR | |OP_CODESEPARATOR | ||
|171 | |||
|Nothing | |Nothing | ||
|Nothing | |Nothing | ||
| Line 420: | Line 551: | ||
|- | |- | ||
|OP_CHECKSIG | |OP_CHECKSIG | ||
|172 | |||
|sig pubkey | |sig pubkey | ||
|True / false | |True / false | ||
| Line 425: | Line 557: | ||
|- | |- | ||
|OP_CHECKSIGVERIFY | |OP_CHECKSIGVERIFY | ||
|173 | |||
|sig pubkey | |sig pubkey | ||
|True / false | |True / false | ||
| Line 430: | Line 563: | ||
|- | |- | ||
|OP_CHECKMULTISIG | |OP_CHECKMULTISIG | ||
|174 | |||
|sig1 sig2 ... <number of signatures> pub1 pub2 <number of public keys> | |sig1 sig2 ... <number of signatures> pub1 pub2 <number of public keys> | ||
|True / False | |True / False | ||
| Line 435: | Line 569: | ||
|- | |- | ||
|OP_CHECKMULTISIGVERIFY | |OP_CHECKMULTISIGVERIFY | ||
|175 | |||
|sig1 sig2 ... <number of signatures> pub1 pub2 ... <number of public keys> | |sig1 sig2 ... <number of signatures> pub1 pub2 ... <number of public keys> | ||
|True / False | |True / False | ||
|Same as OP_CHECKMULTISIG, but OP_VERIFY is executed afterward. | |Same as OP_CHECKMULTISIG, but OP_VERIFY is executed afterward. | ||
|} | |||
===Pseudo-words=== | |||
These words are used internally for assisting with transaction matching. They are invalid if used in actual scripts. | |||
{| class="wikitable" | |||
|- | |||
!Word | |||
!Opcode | |||
!Description | |||
|- | |||
|OP_PUBKEYHASH | |||
|253 | |||
|Represents a public key hashed with OP_HASH160. | |||
|- | |||
|OP_PUBKEY | |||
|254 | |||
|Represents a public key compatible with OP_CHECKSIG. | |||
|- | |||
|OP_INVALIDOPCODE | |||
|255 | |||
|Matches any opcode that is not yet assigned. | |||
|} | |||
=== Reserved words === | |||
Any opcode not assigned is also reserved. Using an unassigned opcode makes the transaction invalid. | |||
{| class="wikitable" | |||
|- | |||
!Word | |||
!Opcode | |||
!When used... | |||
|- | |||
|OP_RESERVED | |||
|80 | |||
|Transaction is invalid | |||
|- | |||
|OP_VER | |||
|98 | |||
|Transaction is invalid | |||
|- | |||
|OP_VERIF | |||
|101 | |||
|Transaction is invalid | |||
|- | |||
|OP_VERNOTIF | |||
|102 | |||
|Transaction is invalid | |||
|- | |||
|OP_RESERVED1 | |||
|137 | |||
|Transaction is invalid | |||
|- | |||
|OP_RESERVED2 | |||
|138 | |||
|Transaction is invalid | |||
|- | |||
|OP_NOP1-OP_NOP10 | |||
|176-185 | |||
|The word is ignored. | |||
|} | |} | ||
== Scripts == | == Scripts == | ||
Keep in mind that all constants actually use the data-pushing commands above. | |||
=== Standard Transaction to Bitcoin address === | === Standard Transaction to Bitcoin address === | ||
| Line 447: | Line 642: | ||
scriptSig: <sig> <pubKey> | scriptSig: <sig> <pubKey> | ||
To demonstrate how scripts look on the wire, here is a raw scriptPubKey: | |||
<pre> 76 A9 14 | |||
OP_DUP OP_HASH160 Bytes to push | |||
AB CD EF AB BA AB BA AB BA AB BA AB BA AB BA AB BA AB BA 88 AC | |||
Data to push OP_EQUALVERIFY OP_CHECKSIG</pre> | |||
Here is how each word is processed: | |||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
| Line 475: | Line 678: | ||
|<sig <pubKey> | |<sig <pubKey> | ||
|OP_CHECKSIG | |OP_CHECKSIG | ||
| | |||
| Equality is checked between the top two stack items. | | Equality is checked between the top two stack items. | ||
|- | |- | ||
| Line 487: | Line 691: | ||
scriptSig: <sig> | scriptSig: <sig> | ||
Checking process: | |||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
| Line 529: | Line 734: | ||
|<sig> <pubKey> | |<sig> <pubKey> | ||
|OP_CHECKSIG | |OP_CHECKSIG | ||
| | |||
|Top item in the stack is removed. | |Top item in the stack is removed. | ||
|- | |- | ||
Revision as of 18:23, 21 December 2010
Bitcoin uses a scripting system for transactions. Forth-like, Script is simple, stack-based, and processed from left to right. It is purposefully not Turing-complete, with no loops or nesting if statements.
A transaction is valid if nothing in the combined script triggers failure and the top stack item is true (1).
Scripts are big-endian. (Is all data, also?)
Words
This is a list of all Script words (commands/functions). Some are currently disabled for security reasons.
True=1 and False=0.
Constants
When talking about scripts, these value-pushing words are usually omitted.
| Word | Opcode | Input | Output | Description |
|---|---|---|---|---|
| OP_0, OP_FALSE | 0 | Nothing. | 0 | The number 0 is pushed onto the stack. |
| N/A | 1-75 | (special) | data | The next opcode bytes is data to be pushed onto the stack |
| OP_PUSHDATA1 | 76 | (special) | data | The next byte contains the number of bytes to be pushed onto the stack. |
| OP_PUSHDATA2 | 77 | (special) | data | The next two bytes contain the number of bytes to be pushed onto the stack. |
| OP_PUSHDATA4 | 78 | (special) | data | The next four bytes contain the number of bytes to be pushed onto the stack. |
| OP_1NEGATE | 79 | Nothing. | -1 | The number -1 is pushed onto the stack. |
| OP_1, OP_TRUE | 81 | Nothing. | 1 | The number 1 is pushed onto the stack. |
| OP_2-OP_16 | 82-96 | Nothing. | 2-16 | The number in the word name (2-16) is pushed onto the stack. |
Flow control
| Word | Opcode | Input | Output | Description |
|---|---|---|---|---|
| OP_NOP | 97 | Nothing | Nothing | Does nothing. |
| OP_IF | 99 | <expression> if [statements] [else [statements]] endif | If the top stack value is 1, the statements are executed. The top stack value is removed. | |
| OP_NOTIF | 100 | <expression> if [statements] [else [statements]] endif | If the top stack value is 0, the statements are executed. The top stack value is removed. | |
| OP_ELSE | 103 | <expression> if [statements] [else [statements]] endif | If the preceding OP_IF was not executed, these statements are. | |
| OP_ENDIF | 104 | <expression> if [statements] [else [statements]] endif | Ends an if/else block. | |
| OP_VERIFY | 105 | True / false | Nothing / False | Marks transaction as invalid if top stack value is not true. True is removed, but false is not. |
| OP_RETURN | 106 | Nothing | Nothing | Marks transaction as invalid. |
Stack
| Word | Opcode | Input | Output | Description |
|---|---|---|---|---|
| OP_TOALTSTACK | 107 | x1 | (alt)x1 | Puts the input onto the top of the alt stack. Removes it from the main stack. |
| OP_FROMALTSTACK | 108 | (alt)x1 | x1 | Puts the input onto the top of the main stack. Removes it from the alt stack. |
| OP_IFDUP | 115 | x | x / x x | If the input is true or false, duplicate it. |
| OP_DEPTH | 116 | Nothing | <Stack size> | Puts the number of stack items onto the stack. |
| OP_DROP | 117 | x | Nothing | Removes the top stack item. |
| OP_DUP | 118 | x | x x | Duplicates the top stack item. |
| OP_NIP | 119 | x1 x2 | x2 | Removes the second-to-top stack item. |
| OP_OVER | 120 | x1 x2 | x1 x2 x1 | Copies the second-to-top stack item to the top. |
| OP_PICK | 121 | xn ... x2 x1 x0 <n> | xn ... x2 x1 x0 xn | The item n back in the stack is copied to the top. |
| OP_ROLL | 122 | xn ... x2 x1 x0 <n> | ... x2 x1 x0 xn | The item n back in the stack is moved to the top. |
| OP_ROT | 123 | x1 x2 x3 | x2 x3 x1 | The top three items on the stack are rotated to the left. |
| OP_SWAP | 124 | x1 x2 | x2 x1 | The top two items on the stack are swapped. |
| OP_TUCK | 125 | x1 x2 | x2 x1 x2 | The item at the top of the stack is copied and inserted before the second-to-top item. |
| OP_2DROP | 109 | x1 x2 | Nothing | Removes the top two stack items. |
| OP_2DUP | 110 | x1 x2 | x1 x2 x1 x2 | Duplicates the top two stack items. |
| OP_3DUP | 111 | x1 x2 x3 | x1 x2 x3 x1 x2 x3 | Duplicates the top three stack items. |
| OP_2OVER | 112 | x1 x2 x3 x4 | x1 x2 x3 x4 x1 x2 | Copies the pair of items two spaces back in the stack to the front. |
| OP_2ROT | 113 | x1 x2 x3 x4 x5 x6 | x3 x4 x5 x6 x1 x2 | The fifth and sixth items back are moved to the top of the stack. |
| OP_2SWAP | 114 | x1 x2 x3 x4 | x3 x4 x1 x2 | Swaps the top two pairs of items. |
Splice
| Word | Opcode | Input | Output | Description |
|---|---|---|---|---|
| OP_CAT | 126 | x1 x2 | out | Concatenates two strings. Currently disabled. |
| OP_SUBSTR | 127 | in begin size | out | Returns a section of a string. Currently disabled. |
| OP_LEFT | 128 | in size | out | Keeps only characters left of the specified point in a string. Currently disabled. |
| OP_RIGHT | 129 | in size | out | Keeps only characters right of the specified point in a string. Currently disabled. |
| OP_SIZE | 130 | in | in size | Returns the length of the input string. |
Bitwise logic
| Word | Input | Output | Description | |
|---|---|---|---|---|
| OP_INVERT | 131 | in | out | Flips all of the bits in the input. Currently disabled. |
| OP_AND | 132 | x1 x2 | out | Boolean and between each bit in the inputs. Currently disabled. |
| OP_OR | 133 | x1 x2 | out | Boolean or between each bit in the inputs. Currently disabled. |
| OP_XOR | 134 | x1 x2 | out | Boolean exclusive or between each bit in the inputs. Currently disabled. |
| OP_EQUAL | 135 | x1 x2 | True / false | Returns 1 if the inputs are exactly equal, 0 otherwise. |
| OP_EQUALVERIFY | 136 | x1 x2 | True / false | Same as OP_EQUAL, but runs OP_VERIFY afterward. |
Arithmetic
| Word | Opcode | Input | Output | Description |
|---|---|---|---|---|
| OP_1ADD | 139 | in | out | 1 is added to the input. |
| OP_1SUB | 140 | in | out | 1 is subtracted from the input. |
| OP_2MUL | 141 | in | out | The input is multiplied by 2. Currently disabled. |
| OP_2DIV | 142 | in | out | The input is divided by 2. Currently disabled. |
| OP_NEGATE | 143 | in | out | The sign of the input is flipped. |
| OP_ABS | 144 | in | out | The input is made positive. |
| OP_NOT | 145 | in | out | If the input is 0 or 1, it is flipped. Otherwise the output will be 0. |
| OP_0NOTEQUAL | 146 | in | out | Returns 1 if the input is 0. 0 otherwise. |
| OP_ADD | 147 | a b | out | a is added to b. |
| OP_SUB | 148 | a b | out | b is subtracted from a. |
| OP_MUL | 149 | a b | out | a is multiplied by b. Currently disabled. |
| OP_DIV | 150 | a b | out | a is divided by b. Currently disabled. |
| OP_MOD | 151 | a b | out | Returns the remainder after dividing a by b. Currently disabled. |
| OP_LSHIFT | 152 | a b | out | Shifts a left b bits, preserving sign. Currently disabled. |
| OP_RSHIFT | 153 | a b | out | Shifts a right b bits, preserving sign. Currently disabled. |
| OP_BOOLAND | 154 | a b | out | If both a and b are not 0, the output is 1. Otherwise 0. |
| OP_BOOLOR | 155 | a b | out | If a or b is not 0, the output is 1. Otherwise 0. |
| OP_NUMEQUAL | 156 | a b | out | Returns 1 if the numbers are equal, 0 otherwise. |
| OP_NUMEQUALVERIFY | 157 | a b | out | Same as OP_NUMEQUAL, but runs OP_VERIFY afterward. |
| OP_NUMNOTEQUAL | 158 | a b | out | Returns 1 if the numbers are not equal, 0 otherwise. |
| OP_LESSTHAN | 159 | a b | out | Returns 1 if a is less than b, 0 otherwise. |
| OP_GREATERTHAN | 160 | a b | out | Returns 1 if a is greater than b, 0 otherwise. |
| OP_LESSTHANOREQUAL | 161 | a b | out | Returns 1 if a is less than or equal to b, 0 otherwise. |
| OP_GREATERTHANOREQUAL | 162 | a b | out | Returns 1 if a is greater than or equal to b, 0 otherwise. |
| OP_MIN | 163 | a b | out | Returns the smaller of a and b. |
| OP_MAX | 164 | a b | out | Returns the larger of a and b. |
| OP_WITHIN | 165 | x min max | out | Returns 1 if x is within the specified range (left-inclusive), 0 otherwise. |
Crypto
| Word | Opcode | Input | Output | Description |
|---|---|---|---|---|
| OP_RIPEMD160 | 166 | in | hash | The input is hashed using RIPEMD-160. |
| OP_SHA1 | 167 | in | hash | The input is hashed using SHA-1. |
| OP_SHA256 | 168 | in | hash | The input is hashed using SHA-256. |
| OP_HASH160 | 169 | in | hash | The input is hashed twice: first with SHA-256 and then with RIPEMD-160. |
| OP_HASH256 | 170 | in | hash | The input is hashed two times with SHA-256. |
| OP_CODESEPARATOR | 171 | Nothing | Nothing | All of the signature checking words will only match signatures to the data after the most recently-executed OP_CODESEPARATOR. |
| OP_CHECKSIG | 172 | sig pubkey | True / false | The entire transaction's outputs, inputs, and script (from the most recently-executed OP_CODESEPARATOR to the end) are hashed. The signature used by OP_CHECKSIG must be a valid signature for this hash and public key. If it is, 1 is returned, 0 otherwise. |
| OP_CHECKSIGVERIFY | 173 | sig pubkey | True / false | Same as OP_CHECKSIG, but OP_VERIFY is executed afterward. |
| OP_CHECKMULTISIG | 174 | sig1 sig2 ... <number of signatures> pub1 pub2 <number of public keys> | True / False | For each signature and public key pair, OP_CHECKSIG is executed. If more public keys than signatures are listed, some key/sig pairs can fail. All signatures need to match a public key. If all signatures are valid, 1 is returned, 0 otherwise. |
| OP_CHECKMULTISIGVERIFY | 175 | sig1 sig2 ... <number of signatures> pub1 pub2 ... <number of public keys> | True / False | Same as OP_CHECKMULTISIG, but OP_VERIFY is executed afterward. |
Pseudo-words
These words are used internally for assisting with transaction matching. They are invalid if used in actual scripts.
| Word | Opcode | Description |
|---|---|---|
| OP_PUBKEYHASH | 253 | Represents a public key hashed with OP_HASH160. |
| OP_PUBKEY | 254 | Represents a public key compatible with OP_CHECKSIG. |
| OP_INVALIDOPCODE | 255 | Matches any opcode that is not yet assigned. |
Reserved words
Any opcode not assigned is also reserved. Using an unassigned opcode makes the transaction invalid.
| Word | Opcode | When used... |
|---|---|---|
| OP_RESERVED | 80 | Transaction is invalid |
| OP_VER | 98 | Transaction is invalid |
| OP_VERIF | 101 | Transaction is invalid |
| OP_VERNOTIF | 102 | Transaction is invalid |
| OP_RESERVED1 | 137 | Transaction is invalid |
| OP_RESERVED2 | 138 | Transaction is invalid |
| OP_NOP1-OP_NOP10 | 176-185 | The word is ignored. |
Scripts
Keep in mind that all constants actually use the data-pushing commands above.
Standard Transaction to Bitcoin address
scriptPubKey: OP_DUP OP_HASH160 <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG scriptSig: <sig> <pubKey>
To demonstrate how scripts look on the wire, here is a raw scriptPubKey:
76 A9 14
OP_DUP OP_HASH160 Bytes to push
AB CD EF AB BA AB BA AB BA AB BA AB BA AB BA AB BA AB BA 88 AC
Data to push OP_EQUALVERIFY OP_CHECKSIG
Here is how each word is processed:
| Stack | Script | Description | |
|---|---|---|---|
| Empty. | <sig> <pubKey> OP_DUP OP_HASH160 <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG | scriptSig and scriptPubKey are combined. | |
| <sig> <pubKey> | OP_DUP OP_HASH160 <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG | Constants are added to the stack. | |
| <sig> <pubKey> <pubKey> | OP_HASH160 <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG | Top stack item is duplicated. | |
| <sig <pubKey> <pubHashA> | <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG | Top stack item is hashed. | |
| <sig <pubKey> <pubHashA> <pubKeyHash> | OP_EQUALVERIFY OP_CHECKSIG | Constant added. | |
| <sig <pubKey> | OP_CHECKSIG | Equality is checked between the top two stack items. | |
| true | Empty. | Signature is checked for top two stack items. |
Standard Generation / transaction to IP address
scriptPubKey: <pubKey> OP_CHECKSIG scriptSig: <sig>
Checking process:
| Stack | Script | Description |
|---|---|---|
| Empty. | <sig> <pubKey> OP_CHECKSIG | scriptSig and scriptPubKey are combined. |
| <sig> <pubKey> | OP_CHECKSIG | Constants are added to the stack. |
| true | Empty. | Signature is checked for top two stack items. |
Transaction with a message
It's possible to add arbitrary data to any transaction by just adding some data along with OP_DROP (or ommitting OP_DROP and allowing the value to sit on the stack unused). Scripts are limited to 10,000 bytes and 201 instructions/values, and each individual instruction/value is limited to 520 bytes.
scriptPubKey: <message> OP_DROP <pubKey> OP_CHECKSIG scriptSig: <sig>
| Stack | Script | Description | |
|---|---|---|---|
| Empty. | <sig> <pubKey> OP_CHECKSIG | scriptSig and scriptPubKey are combined. | |
| <sig> <pubKey> <message> | OP_DROP OP_CHECKSIG | Constants are added to the stack. | |
| <sig> <pubKey> | OP_CHECKSIG | Top item in the stack is removed. | |
| true | Empty. | Signature is checked for top two stack items. |