Opcodes used in Bitcoin Script
(Redirected from Opcodes)
This is a list of all Script words, also known as opcodes, commands, or functions.
OP_NOP1OP_NOP10 were originally set aside to be used when HASH and other security functions become insecure due to improvements in computing.
False is zero or negative zero (using any number of bytes) or an empty array, and True is anything else.
Constants
When talking about scripts, these valuepushing words are usually omitted.
Word  Opcode  Hex  Input  Output  Description 

OP_0, OP_FALSE  0  0x00  Nothing.  (empty value)  An empty array of bytes is pushed onto the stack. (This is not a noop: an item is added to the stack.) 
Pushdata Bytelength  175  0x010x4b  (special)  data  The next opcode bytes is data to be pushed onto the stack 
OP_PUSHDATA1  76  0x4c  (special)  data  The next byte contains the number of bytes to be pushed onto the stack. 
OP_PUSHDATA2  77  0x4d  (special)  data  The next two bytes contain the number of bytes to be pushed onto the stack in little endian order. 
OP_PUSHDATA4  78  0x4e  (special)  data  The next four bytes contain the number of bytes to be pushed onto the stack in little endian order. 
OP_1NEGATE  79  0x4f  Nothing.  1  The number 1 is pushed onto the stack. 
OP_1, OP_TRUE  81  0x51  Nothing.  1  The number 1 is pushed onto the stack. 
OP_2OP_16  8296  0x520x60  Nothing.  216  The number in the word name (216) is pushed onto the stack. 
Flow control
Word  Opcode  Hex  Input  Output  Description 

OP_NOP  97  0x61  Nothing  Nothing  Does nothing. 
OP_VER DISABLED  98  0x62  Nothing  Protocol version  Puts the version of the protocol under which this transaction will be evaluated onto the stack. 
OP_IF  99  0x63 

If the top stack value is TRUE, statement 1 is executed.
If the top stack value is FALSE and ELSE is used, statement 2 is executed. If ELSE is NOT used, the script jumps to ENDIF.  
OP_NOTIF  100  0x64 

If the top stack value is FALSE, statement 1 is executed.
If the top stack value is TRUE and ELSE is used, statement 2 is executed. If ELSE is NOT used, the script jumps to ENDIF.  
OP_VERIF DISABLED  101  0x65  DISABLED  DISABLED  
OP_VERNOTIF DISABLED  102  0x66  DISABLED  DISABLED  
OP_ELSE  103  0x67 

If the preceding IF or NOTIF check was not valid then statement 2 is executed.  
OP_ENDIF  104  0x68 

Ends an if/else block. All blocks must end, or the transaction is invalid. An OP_ENDIF without a prior matching OP_IF or OP_NOTIF is also invalid.  
OP_VERIFY  105  0x69  True / false  Nothing / fail  Marks transaction as invalid if top stack value is not true. The top stack value is removed. 
OP_RETURN  106  0x6a  Nothing  Ends script with top value on stack as final result  OP_RETURN can also be used to create "False Return" outputs with a scriptPubKey consisting of OP_FALSE OP_RETURN followed by data. Such outputs are provably unspendable and should be given a value of zero Satoshis. These outputs can be pruned from storage in the UTXO set, reducing its size. Currently the BitcoinSV network supports multiple FALSE RETURN outputs in a given transaction with each one capable of holding up to 100kB of data. After the Genesis upgrade in 2020 miners will be free to mine transactions containing FALSE RETURN outputs of any size. 
Stack
Word  Opcode  Hex  Input  Output  Description 

OP_TOALTSTACK  107  0x6b  x1  (alt)x1  Puts the input onto the top of the alt stack. Removes it from the main stack. 
OP_FROMALTSTACK  108  0x6c  (alt)x1  x1  Puts the input onto the top of the main stack. Removes it from the alt stack. 
OP_2DROP  109  0x6d  x1 x2  Nothing  Removes the top two stack items. 
OP_2DUP  110  0x6e  x1 x2  x1 x2 x1 x2  Duplicates the top two stack items. 
OP_3DUP  111  0x6f  x1 x2 x3  x1 x2 x3 x1 x2 x3  Duplicates the top three stack items. 
OP_2OVER  112  0x70  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  0x71  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  0x72  x1 x2 x3 x4  x3 x4 x1 x2  Swaps the top two pairs of items. 
OP_IFDUP  115  0x73  x  x / x x  If the top stack value is not 0, duplicate it. 
OP_DEPTH  116  0x74  Nothing  <Stack size>  Counts the number of stack items onto the stack and places the value on the top 
OP_DROP  117  0x75  x  Nothing  Removes the top stack item. 
OP_DUP  118  0x76  x  x x  Duplicates the top stack item. 
OP_NIP  119  0x77  x1 x2  x2  Removes the secondtotop stack item. 
OP_OVER  120  0x78  x1 x2  x1 x2 x1  Copies the secondtotop stack item to the top. 
OP_PICK  121  0x79  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  0x7a  xn ... x2 x1 x0 <n>  ... x2 x1 x0 xn  The item n back in the stack is moved to the top. 
OP_ROT  123  0x7b  x1 x2 x3  x2 x3 x1  The top three items on the stack are rotated to the left. 
OP_SWAP  124  0x7c  x1 x2  x2 x1  The top two items on the stack are swapped. 
OP_TUCK  125  0x7d  x1 x2  x2 x1 x2  The item at the top of the stack is copied and inserted before the secondtotop item. 
Data Manipulation
Word  Opcode  Hex  Input  Output  Description 

OP_CAT  126  0x7e  x1 x2  out  Concatenates two strings. 
OP_SPLIT  127  0x7f  x n  x1 x2  Splits byte sequence x at position n. 
OP_NUM2BIN  128  0x80  a b  out  Converts numeric value a into byte sequence of length b. 
OP_BIN2NUM  129  0x81  x  out  Converts byte sequence x into a numeric value. 
OP_SIZE  130  0x82  in  in size  Pushes the string length of the top element of the stack (without popping it). 
Bitwise logic
Word  Opcode  Hex  Input  Output  Description 

OP_INVERT  131  0x83  in  out  Flips all of the bits in the input. 
OP_AND  132  0x84  x1 x2  out  Boolean and between each bit in the inputs. 
OP_OR  133  0x85  x1 x2  out  Boolean or between each bit in the inputs. 
OP_XOR  134  0x86  x1 x2  out  Boolean exclusive or between each bit in the inputs. 
OP_EQUAL  135  0x87  x1 x2  True / false  Returns 1 if the inputs are exactly equal, 0 otherwise. 
OP_EQUALVERIFY  136  0x88  x1 x2  Nothing / fail  Same as OP_EQUAL, but runs OP_VERIFY afterward. 
Arithmetic
BitcoinScript supports arithmetic on bignum values A bignum is a byte sequence that represents a numeric value. The length of the byte sequence must be less than or equal to 750,000 bytes. Byte sequences larger than 750,000 bytes are valid in Bitcoin however current rules dictate that they are not recognised as a valid numeric value.
Note that while some operations require parameters to be valid numeric values, they may produce byte sequences which are not valid numeric values (for example, OP_MUL may produce a byte sequence which is too large to validly represent a numeric value).
Word  Opcode  Hex  Input  Output  Description 

OP_1ADD  139  0x8b  in  out  1 is added to the input. 
OP_1SUB  140  0x8c  in  out  1 is subtracted from the input. 
OP_2MUL DISABLED  141  0x8d  in  out  The input is multiplied by 2. (This opcode is scheduled to be reenabled in the Chronicle update) 
OP_2DIV DISABLED  142  0x8e  in  out  The input is divided by 2. (This opcode is scheduled to be reenabled in the Chronicle update) 
OP_NEGATE  143  0x8f  in  out  The sign of the input is flipped. 
OP_ABS  144  0x90  in  out  The input is made positive. 
OP_NOT  145  0x91  in  out  If the input is 0 or 1, it is flipped. Otherwise the output will be 0. 
OP_0NOTEQUAL  146  0x92  in  out  Returns 0 if the input is 0. 1 otherwise. 
OP_ADD  147  0x93  a b  out  a is added to b. 
OP_SUB  148  0x94  a b  out  b is subtracted from a. 
OP_MUL  149  0x95  a b  out  a is multiplied by b. 
OP_DIV  150  0x96  a b  out  a is divided by b. 
OP_MOD  151  0x97  a b  out  Returns the remainder after dividing a by b. 
OP_LSHIFT  152  0x98  a b  out  Logical left shift b bits. Sign data is discarded 
OP_RSHIFT  153  0x99  a b  out  Logical right shift b bits. Sign data is discarded 
OP_BOOLAND  154  0x9a  a b  out  If both a and b are not 0, the output is 1. Otherwise 0. 
OP_BOOLOR  155  0x9b  a b  out  If a or b is not 0, the output is 1. Otherwise 0. 
OP_NUMEQUAL  156  0x9c  a b  out  Returns 1 if the numbers are equal, 0 otherwise. 
OP_NUMEQUALVERIFY  157  0x9d  a b  Nothing / fail  Same as OP_NUMEQUAL, but runs OP_VERIFY afterward. 
OP_NUMNOTEQUAL  158  0x9e  a b  out  Returns 1 if the numbers are not equal, 0 otherwise. 
OP_LESSTHAN  159  0x9f  a b  out  Returns 1 if a is less than b, 0 otherwise. 
OP_GREATERTHAN  160  0xa0  a b  out  Returns 1 if a is greater than b, 0 otherwise. 
OP_LESSTHANOREQUAL  161  0xa1  a b  out  Returns 1 if a is less than or equal to b, 0 otherwise. 
OP_GREATERTHANOREQUAL  162  0xa2  a b  out  Returns 1 if a is greater than or equal to b, 0 otherwise. 
OP_MIN  163  0xa3  a b  out  Returns the smaller of a and b. 
OP_MAX  164  0xa4  a b  out  Returns the larger of a and b. 
OP_WITHIN  165  0xa5  x min max  out  Returns 1 if x is within the specified range (leftinclusive), 0 otherwise. 
Cryptography
Word  Opcode  Hex  Input  Output  Description 

OP_RIPEMD160  166  0xa6  in  hash  The input is hashed using RIPEMD160. 
OP_SHA1  167  0xa7  in  hash  The input is hashed using SHA1. 
OP_SHA256  168  0xa8  in  hash  The input is hashed using SHA256. 
OP_HASH160  169  0xa9  in  hash  The input is hashed twice: first with SHA256 and then with RIPEMD160. 
OP_HASH256  170  0xaa  in  hash  The input is hashed two times with SHA256. 
OP_CODESEPARATOR  171  0xab  Nothing  Nothing  All of the signature checking words will only match signatures to the data after the most recentlyexecuted OP_CODESEPARATOR. 
OP_CHECKSIG  172  0xac  sig pubkey  True / false  The entire transaction's outputs, inputs, and script (from the most recentlyexecuted 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  0xad  sig pubkey  Nothing / fail  Same as OP_CHECKSIG, but OP_VERIFY is executed afterward. 
OP_CHECKMULTISIG  174  0xae  x sig1 sig2 ... <number of signatures> pub1 pub2 <number of public keys>  True / False  Compares the first signature against each public key until it finds an ECDSA match. Starting with the subsequent public key, it compares the second signature against each remaining public key until it finds an ECDSA match. The process is repeated until all signatures have been checked or not enough public keys remain to produce a successful result. All signatures need to match a public key. Because public keys are not checked again if they fail any signature comparison, signatures must be placed in the scriptSig using the same order as their corresponding public keys were placed in the scriptPubKey or redeemScript. If all signatures are valid, 1 is returned, 0 otherwise. Due to a bug, an extra unused value (x) is removed from the stack. Script spenders must account for this by adding a junk value (typically zero) to the stack. 
OP_CHECKMULTISIGVERIFY  175  0xaf  x sig1 sig2 ... <number of signatures> pub1 pub2 ... <number of public keys>  Nothing / fail  Same as OP_CHECKMULTISIG, but OP_VERIFY is executed afterward. 
Used NOP opcode identifiers
In Bitcoin's history, new opcodes were added that used reserved NO_OP opcode identifiers. These opcodes have been reverted to the original OP_NOP functionality.
Word  Opcode  Hex  Input  Output  Description 

OP_NOP2
(previously OP_CHECKLOCKTIMEVERIFY) 
177  0xb1  Nothing
(Previously: x) 
Nothing
(Previously: x or fail) 
NO OPERATION
Evaluation process for UTXOs that predate genesis: Mark transaction as invalid if the top stack item is greater than the transaction's nLockTime field, otherwise script evaluation continues as though an OP_NOP was executed. Transaction is also invalid if 1. the stack is empty; or 2. the top stack item is negative; or 3. the top stack item is greater than or equal to 500000000 while the transaction's nLockTime field is less than 500000000, or vice versa; or 4. the input's nSequence field is equal to 0xffffffff. The precise semantics are described in BIP 0065. 
OP_NOP3
(previously OP_CHECKSEQUENCEVERIFY) 
178  0xb2  Nothing
(Previously: x) 
Nothing
(Previously: x or fail) 
NO OPERATION
Evaluation process for UTXOs that predate genesis: Mark transaction as invalid if the relative lock time of the input (enforced by BIP 0068 with nSequence) is not equal to or longer than the value of the top stack item. The precise semantics are described in BIP 0112. 
Pseudowords
These words are used internally for assisting with transaction matching. They are invalid if used in actual scripts.
Word  Opcode  Hex  Description 

OP_PUBKEYHASH  253  0xfd  Represents a public key hashed with OP_HASH160. 
OP_PUBKEY  254  0xfe  Represents a public key compatible with OP_CHECKSIG. 
OP_INVALIDOPCODE  255  0xff  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  Hex  When used... 

OP_RESERVED  80  0x50  Transaction is invalid unless occuring in an unexecuted OP_IF branch 
OP_RESERVED1  137  0x89  Transaction is invalid unless occuring in an unexecuted OP_IF branch 
OP_RESERVED2  138  0x8a  Transaction is invalid unless occuring in an unexecuted OP_IF branch 
OP_NOP1, OP_NOP4OP_NOP10  176, 179185  0xb0, 0xb30xb9  The word is ignored. Does not mark transaction as invalid. 
Examples
For examples of common Bitcoin transaction scripts please see Bitcoin Transactions
Attribution
This content is based on content sourced from https://en.bitcoin.it/wiki/Script under Creative Commons Attribution 3.0. Although it may have been extensively revised and updated we acknowledge the original authors.