Bitcoin Script VM in Cairo

Overview

shinigami is a Bitcoin Script library for generic Script VM execution in Cairo, enabling the generation of STARK proofs for Bitcoin Script computation and Bitcoin transaction execution.

Key features ( will include ) :

• Bitcoin Script interpretation and execution
• Frontend Script IDE with STARK prover integration
• Transaction execution and proving
• Easily configurable VM ( enable different opcodes )
• In cairo, Bitcoin Script compiler

Usage

Running

scarb cairo-run --available-gas=200000000

This will run the provided Bitcoin Script in Cairo.

Building

scarb build

This will compile all the components.

Testing

scarb test

This will run the test-suite for all opcodes, integration, and testing Scripts.

Supported Opcodes

104/107 opcodes supported (97.20%).

%%{init: {"pie": {"textPosition": 0.75}, "themeVariables": {"pieOuterStrokeWidth": "5px"}} }%%
pie showData
    title Opcode Implementation Status
    "Implemented" : 89
    "Disabled" : 15
    "Not Implemented" : 3

Loading

Opcode	Hex	Supported	Description
OP_0 / OP_FALSE	0x00	✅	An empty array of bytes is pushed onto the stack.
OP_DATA_1-OP_DATA_75	0x01-0x4b	✅	The next opcode bytes is data to be pushed onto the stack.
OP_PUSHDATA1	0x4c	✅	The next byte contains the number of bytes to be pushed onto the stack.
OP_PUSHDATA2	0x4d	✅	The next two bytes contain the number of bytes to be pushed onto the stack in little endian order.
OP_PUSHDATA4	0x4e	✅	The next four bytes contain the number of bytes to be pushed onto the stack in little endian order.
OP_1NEGATE	0x4f	✅	The number -1 is pushed onto the stack.
OP_RESERVED	0x50	✅	Transaction is invalid unless occurring in an unexecuted OP_IF branch
OP_1 / OP_TRUE	0x51	✅	The number 1 is pushed onto the stack.
OP_2	0x52	✅	The number 2 is pushed onto the stack.
OP_3	0x53	✅	The number 3 is pushed onto the stack.
OP_4	0x54	✅	The number 4 is pushed onto the stack.
OP_5	0x55	✅	The number 5 is pushed onto the stack.
OP_6	0x56	✅	The number 6 is pushed onto the stack.
OP_7	0x57	✅	The number 7 is pushed onto the stack.
OP_8	0x58	✅	The number 8 is pushed onto the stack.
OP_9	0x59	✅	The number 9 is pushed onto the stack.
OP_10	0x5a	✅	The number 10 is pushed onto the stack.
OP_11	0x5b	✅	The number 11 is pushed onto the stack.
OP_12	0x5c	✅	The number 12 is pushed onto the stack.
OP_13	0x5d	✅	The number 13 is pushed onto the stack.
OP_14	0x5e	✅	The number 14 is pushed onto the stack.
OP_15	0x5f	✅	The number 15 is pushed onto the stack.
OP_16	0x60	✅	The number 16 is pushed onto the stack.
OP_NOP	0x61	✅	Does nothing.
OP_VER	0x62	✅	Transaction is invalid unless occurring in an unexecuted OP_IF branch
OP_IF	0x63	✅	If the top stack value is not False, the statements are executed. The top stack value is removed.
OP_NOTIF	0x64	✅	If the top stack value is False, the statements are executed. The top stack value is removed.
OP_VERIF	0x65	✅	Transaction is invalid even when occurring in an unexecuted OP_IF branch
OP_VERNOTIF	0x66	✅	Transaction is invalid even when occurring in an unexecuted OP_IF branch
OP_ELSE	0x67	✅	If the preceding OP_IF or OP_NOTIF or OP_ELSE was not executed then these statements are and if the preceding OP_IF or OP_NOTIF or OP_ELSE was executed then these statements are not.
OP_ENDIF	0x68	✅	Ends an if/else block.
OP_VERIFY	0x69	✅	Marks transaction as invalid if top stack value is not true.
OP_RETURN	0x6a	✅	Marks transaction as invalid.
OP_TOALTSTACK	0x6b	✅	Puts the input onto the top of the alt stack. Removes it from the main stack.
OP_FROMALTSTACK	0x6c	✅	Puts the input onto the top of the main stack. Removes it from the alt stack.
OP_2DROP	0x6d	✅	Removes the top two stack items.
OP_2DUP	0x6e	✅	Duplicates the top two stack items.
OP_3DUP	0x6f	✅	Duplicates the top three stack items.
OP_2OVER	0x70	✅	Copies the pair of items two spaces back in the stack to the front.
OP_2ROT	0x71	✅	The fifth and sixth items back are moved to the top of the stack.
OP_2SWAP	0x72	✅	Swaps the top two pairs of items.
OP_IFDUP	0x73	✅	If the top stack value is not 0, duplicate it.
OP_DEPTH	0x74	✅	Puts the number of stack items onto the stack.
OP_DROP	0x75	✅	Removes the top stack item.
OP_DUP	0x76	✅	Duplicates the top stack item.
OP_NIP	0x77	✅	Removes the second-to-top stack item.
OP_OVER	0x78	✅	Copies the second-to-top stack item to the top.
OP_PICK	0x79	✅	The item n back in the stack is copied to the top.
OP_ROLL	0x7a	✅	The item n back in the stack is moved to the top.
OP_ROT	0x7b	✅	The top three items on the stack are rotated to the left.
OP_SWAP	0x7c	✅	The top two items on the stack are swapped.
OP_TUCK	0x7d	✅	The item at the top of the stack is copied and inserted before the second-to-top item.
OP_CAT	0x7e	❗	Concatenates two strings. Disabled.
OP_SUBSTR	0x7f	❗	Returns a section of a string. Disabled.
OP_LEFT	0x80	❗	Keeps only characters left of the specified point in a string. Disabled.
OP_RIGHT	0x81	❗	Keeps only characters right of the specified point in a string. Disabled.
OP_SIZE	0x82	✅	Pushes the string length of the top element of the stack (without popping it).
OP_INVERT	0x83	❗	Flips all of the bits in the input. Disabled.
OP_AND	0x84	❗	Boolean and between each bit in the inputs. Disabled.
OP_OR	0x85	❗	Boolean or between each bit in the inputs. Disabled.
OP_XOR	0x86	❗	Boolean exclusive or between each bit in the inputs. Disabled.
OP_EQUAL	0x87	✅	Returns 1 if the inputs are exactly equal, 0 otherwise.
OP_EQUALVERIFY	0x88	✅	Same as OP_EQUAL, but runs OP_VERIFY afterward.
OP_RESERVED1	0x89	✅	Transaction is invalid unless occurring in an unexecuted OP_IF branch
OP_RESERVED2	0x8a	✅	Transaction is invalid unless occurring in an unexecuted OP_IF branch
OP_1ADD	0x8b	✅	1 is added to the input.
OP_1SUB	0x8c	✅	1 is subtracted from the input.
OP_2MUL	0x8d	❗	The input is multiplied by 2. Disabled.
OP_2DIV	0x8e	❗	The input is divided by 2. Disabled.
OP_NEGATE	0x8f	✅	The sign of the input is flipped.
OP_ABS	0x90	✅	The input is made positive.
OP_NOT	0x91	✅	If the input is 0 or 1, it is flipped. Otherwise the output will be 0.
OP_0NOTEQUAL	0x92	✅	Returns 0 if the input is 0. 1 otherwise.
OP_ADD	0x93	✅	a is added to b.
OP_SUB	0x94	✅	b is subtracted from a.
OP_MUL	0x95	❗	a is multiplied by b. Disabled.
OP_DIV	0x96	❗	a is divided by b. Disabled.
OP_MOD	0x97	❗	Returns the remainder after dividing a by b. Disabled.
OP_LSHIFT	0x98	❗	Shifts a left b bits, preserving sign. Disabled.
OP_RSHIFT	0x99	❗	Shifts a right b bits, preserving sign. Disabled.
OP_BOOLAND	0x9a	✅	If both a and b are not 0, the output is 1. Otherwise 0.
OP_BOOLOR	0x9b	✅	If a or b is not 0, the output is 1. Otherwise 0.
OP_NUMEQUAL	0x9c	✅	Returns 1 if the numbers are equal, 0 otherwise.
OP_NUMEQUALVERIFY	0x9d	✅	Same as OP_NUMEQUAL, but runs OP_VERIFY afterward.
OP_NUMNOTEQUAL	0x9e	✅	Returns 1 if the numbers are not equal, 0 otherwise.
OP_LESSTHAN	0x9f	✅	Returns 1 if a is less than b, 0 otherwise.
OP_GREATERTHAN	0xa0	✅	Returns 1 if a is greater than b, 0 otherwise.
OP_LESSTHANOREQUAL	0xa1	✅	Returns 1 if a is less than or equal to b, 0 otherwise.
OP_GREATERTHANOREQUAL	0xa2	✅	Returns 1 if a is greater than or equal to b, 0 otherwise.
OP_MIN	0xa3	✅	Returns the smaller of a and b.
OP_MAX	0xa4	✅	Returns the larger of a and b.
OP_WITHIN	0xa5	✅	Returns 1 if x is within the specified range (left-inclusive), 0 otherwise.
OP_RIPEMD160	0xa6	✅	The input is hashed using RIPEMD-160.
OP_SHA1	0xa7	✅	The input is hashed using SHA-1.
OP_SHA256	0xa8	✅	The input is hashed using SHA-256.
OP_HASH160	0xa9	✅	The input is hashed twice: first with SHA-256 and then with RIPEMD-160.
OP_HASH256	0xaa	✅	The input is hashed two times with SHA-256.
OP_CODESEPARATOR	0xab	✅	All of the signature checking words will only match signatures to the data after the most recently-executed OP_CODESEPARATOR.
OP_CHECKSIG	0xac	✅	The entire transaction's outputs, inputs, and script 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	0xad	✅	Same as OP_CHECKSIG, but OP_VERIFY is executed afterward.
OP_CHECKMULTISIG	0xae		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. If all signatures are valid, 1 is returned, 0 otherwise. Due to a bug, one extra unused value is removed from the stack.
OP_CHECKMULTISIGVERIFY	0xaf		Same as OP_CHECKMULTISIG, but OP_VERIFY is executed afterward.
OP_NOP1	0xb0	✅	The word is ignored. Does not mark transaction as invalid.
OP_CHECKLOCKTIMEVERIFY	0xb1	✅	Marks 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.
OP_CHECKSEQUENCEVERIFY	0xb2	✅	Marks transaction as invalid if the relative lock time of the input is not equal to or longer than the value of the top stack item.
OP_NOP4-OP_NOP10	0xb3-0xb9	✅	The word is ignored. Does not mark transaction as invalid.
OP_CHECKSIGADD	0xba		Increments n by one and returns to the stack if the signature is valid for the public key and transaction. Only available in tapscript.

References

• Shinigami Telegram
• Shinigami OnlyDust
• Bitcoin Script Wiki

Acknowledgements

Special thanks for these projects.

• btcd : Bitcoin full node implementation written in Go, which heavily inspired the design of the Bitcoin Script engine in Shinigami. The amazing documentation and comments in btcd have been a gold mine and are appreciated.

Contributors ✨

Also, thanks goes to these wonderful people. Follow the contributors guide if you'd like to take part.

Brandon R 💻	A₿del ∞/21M 🐺 - 🐱 💻	okhai 💻	Supreme Labs 💻	Kazeem Hakeem 💻	lomasson 💻	Prasanna Gautam 💻
Olufemi Olumaiyegun 💻	Xavek 💻	ptisserand 💻	Mubarak Muhammad Aminu 💻	Tristan 💻	Harsh Pratap Singh 💻	j1mbo64 💻
Jackson Xu 💻	Esther Breath 💻	Varun Doshi 💻	Zintarh 💻	Oche 💻	Mystic 💻	Jemiiah 💻
Benedict Ejembi 💻	0xSpyC 💻	Armin Sabouri 💻	oluwapeski 💻	ADR!AN 💻	Yusuf Habib 💻	Oshioke Salaki 💻
Emmanuel Soetan 💻	Mexes 💻	Iwueseiter 💻	Shantel peters. 💻	Nguyen Dao 💻	Hunter001 💻	IsraelRex 🎨
Josue Sandino 💻	martin machiebe 💻