Bitcoin protocol implementation in Zig.

About

btczee is a Bitcoin protocol implementation in Zig. It aims to provide a clean and simple implementation of the Bitcoin protocol. The goal is to have a fully functional Bitcoin node that can be used to interact with the Bitcoin network.

Architecture

You can find the architecture of the project and description of components in the docs/architecture.md file.

graph TD
    Node[Node] --> Network
    Node --> Mempool
    Node --> Wallet
    Node --> Storage
    Node --> Miner

    Network --> Mempool
    Network --> Storage

    Mempool --> Wallet
    Mempool --> Storage

    Wallet --> Storage

    Miner --> Mempool
    Miner --> Storage

    subgraph "Core Components"
        Node
        Network
        Mempool
        Wallet
        Storage
        Miner
    end

    subgraph "Supporting Components"
        Types
        Primitives
        Config
    end

    Node -.-> Types
    Node -.-> Primitives
    Node -.-> Config

    classDef core fill:#f9f,stroke:#333,stroke-width:2px;
    classDef support fill:#bbf,stroke:#333,stroke-width:1px;
    class Node,Network,Mempool,Wallet,Storage,Miner core;
    class Types,Primitives,Config support;

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Run

Usage: btczee [command] [args]

Commands:
  node     <subcommand>
  wallet   <subcommand>

Node

Usage: btczee node <subcommand>

Subcommands:
  help   Display help for node

Example:

zig build run -- node

# OR (after a build)
./zig-out/bin/btczee node

Wallet

Usage: btczee wallet <subcommand>

Subcommands:
  create    Create a new wallet
  load      Load an existing wallet
  help      Display help for wallet

Example:

zig build run -- wallet create

# OR (after a build)
./zig-out/bin/btczee wallet create

Test

zig build test --summary all

Build

zig build -Doptimize=ReleaseFast

Benchmark

zig build bench

Documentation

You can generate the documentation by running the following command:

zig build docs

Roadmap

You can find the roadmap of the project in the docs/roadmap.md file.

License

btczee is licensed under the MIT license. See the LICENSE file for more details.

References

• Bitcoin Core
• Learn me a bitcoin
• Mastering Bitcoin
• Onboarding to Bitcoin Core
• Zig
• Zig Standard Library
• Ziglings

Acknowledgements

• Syndica sig client in Zig, we are using a copy of their time and trace modules. Right now, they are not usable as external dependencies, we hope it will be possible in the future, and if so, we will switch to using their libraries directly.

Supported Opcodes

47/107 opcodes supported (43.92%).

%%{init: {"pie": {"textPosition": 0.75}, "themeVariables": {"pieOuterStrokeWidth": "5px"}} }%%
pie showData
    title Opcode Implementation Status
    "Implemented" : 47
    "Disabled" : 0
    "Not Implemented" : 60

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Opcode	Hex	Supported	Description
op0 / opFalse	0x00	❌	An empty array of bytes is pushed onto the stack.
opData1-opData75	0x01-0x4b	❌	The next opcode bytes is data to be pushed onto the stack.
opPushData1	0x4c	✅	The next byte contains the number of bytes to be pushed onto the stack.
opPushData2	0x4d	✅	The next two bytes contain the number of bytes to be pushed onto the stack in little endian order.
opPushData4	0x4e	✅	The next four bytes contain the number of bytes to be pushed onto the stack in little endian order.
op1Negate	0x4f	✅	The number -1 is pushed onto the stack.
opReserved	0x50	❌	Transaction is invalid unless occurring in an unexecuted opIF branch
op1 / opTrue	0x51	✅	The number 1 is pushed onto the stack.
op2	0x52	✅	The number 2 is pushed onto the stack.
op3	0x53	✅	The number 3 is pushed onto the stack.
op4	0x54	✅	The number 4 is pushed onto the stack.
op5	0x55	✅	The number 5 is pushed onto the stack.
op6	0x56	✅	The number 6 is pushed onto the stack.
op7	0x57	✅	The number 7 is pushed onto the stack.
op8	0x58	✅	The number 8 is pushed onto the stack.
op9	0x59	✅	The number 9 is pushed onto the stack.
op10	0x5a	✅	The number 10 is pushed onto the stack.
op11	0x5b	✅	The number 11 is pushed onto the stack.
op12	0x5c	✅	The number 12 is pushed onto the stack.
op13	0x5d	✅	The number 13 is pushed onto the stack.
op14	0x5e	✅	The number 14 is pushed onto the stack.
op15	0x5f	✅	The number 15 is pushed onto the stack.
op16	0x60	✅	The number 16 is pushed onto the stack.
opNop	0x61	✅	Does nothing.
opVer	0x62	❌	Transaction is invalid unless occurring in an unexecuted opIF branch
opIf	0x63	❌	If the top stack value is not False, the statements are executed. The top stack value is removed.
opNotIf	0x64	❌	If the top stack value is False, the statements are executed. The top stack value is removed.
opVerIf	0x65	❌	Transaction is invalid even when occurring in an unexecuted opIF branch
opVerNotIf	0x66	❌	Transaction is invalid even when occurring in an unexecuted opIF branch
opElse	0x67	❌	If the preceding opIF or opNOTIF or opELSE was not executed then these statements are and if the preceding opIF or opNOTIF or opELSE was executed then these statements are not.
opEndIf	0x68	❌	Ends an if/else block.
opVerify	0x69	✅	Marks transaction as invalid if top stack value is not true.
opReturn	0x6a	✅	Marks transaction as invalid.
opToAltStack	0x6b	✅	Puts the input onto the top of the alt stack. Removes it from the main stack.
opFromAltStack	0x6c	✅	Puts the input onto the top of the main stack. Removes it from the alt stack.
op2Drop	0x6d	✅	Removes the top two stack items.
op2Dup	0x6e	✅	Duplicates the top two stack items.
op3Dup	0x6f	✅	Duplicates the top three stack items.
op2Over	0x70	✅	Copies the pair of items two spaces back in the stack to the front.
op2Rot	0x71	✅	The fifth and sixth items back are moved to the top of the stack.
op2Swap	0x72	✅	Swaps the top two pairs of items.
opIfDup	0x73	✅	If the top stack value is not 0, duplicate it.
opDepth	0x74	✅	Puts the number of stack items onto the stack.
opDrop	0x75	✅	Removes the top stack item.
opDup	0x76	✅	Duplicates the top stack item.
opNip	0x77	✅	Removes the second-to-top stack item.
opOver	0x78	✅	Copies the second-to-top stack item to the top.
opPick	0x79	✅	The item n back in the stack is copied to the top.
opRoll	0x7a	✅	The item n back in the stack is moved to the top.
opRot	0x7b	✅	The top three items on the stack are rotated to the left.
opSwap	0x7c	✅	The top two items on the stack are swapped.
opTuck	0x7d	✅	The item at the top of the stack is copied and inserted before the second-to-top item.
opCat	0x7e	❗	Concatenates two strings. Disabled.
opSubStr	0x7f	❗	Returns a section of a string. Disabled.
opLeft	0x80	❗	Keeps only characters left of the specified point in a string. Disabled.
opRight	0x81	❗	Keeps only characters right of the specified point in a string. Disabled.
opSize	0x82	✅	Pushes the string length of the top element of the stack (without popping it).
opInvert	0x83	❗	Flips all of the bits in the input. Disabled.
opAnd	0x84	❗	Boolean and between each bit in the inputs. Disabled.
opOr	0x85	❗	Boolean or between each bit in the inputs. Disabled.
opXor	0x86	❗	Boolean exclusive or between each bit in the inputs. Disabled.
opEqual	0x87	✅	Returns 1 if the inputs are exactly equal, 0 otherwise.
opEqualVerify	0x88	✅	Same as opEQUAL, but runs opVERIFY afterward.
opReserved1	0x89	❌	Transaction is invalid unless occurring in an unexecuted opIF branch
opReserved2	0x8a	❌	Transaction is invalid unless occurring in an unexecuted opIF branch
op1Add	0x8b	✅	1 is added to the input.
op1Sub	0x8c	✅	1 is subtracted from the input.
op2Mul	0x8d	❗	The input is multiplied by 2. Disabled.
op2Div	0x8e	❗	The input is divided by 2. Disabled.
opNegate	0x8f	✅	The sign of the input is flipped.
opAbs	0x90	✅	The input is made positive.
opNot	0x91	✅	If the input is 0 or 1, it is flipped. Otherwise the output will be 0.
op0NotEqual	0x92	✅	Returns 0 if the input is 0. 1 otherwise.
opAdd	0x93	✅	a is added to b.
opSub	0x94	✅	b is subtracted from a.
opMul	0x95	❗	a is multiplied by b. Disabled.
opDiv	0x96	❗	a is divided by b. Disabled.
opMod	0x97	❗	Returns the remainder after dividing a by b. Disabled.
opLShift	0x98	❗	Shifts a left b bits, preserving sign. Disabled.
opRShift	0x99	❗	Shifts a right b bits, preserving sign. Disabled.
opBoolAnd	0x9a	✅	If both a and b are not 0, the output is 1. Otherwise 0.
opBoolOr	0x9b	✅	If a or b is not 0, the output is 1. Otherwise 0.
opNumEqual	0x9c	✅	Returns 1 if the numbers are equal, 0 otherwise.
opNumEqualVerify	0x9d	✅	Same as opNUMEQUAL, but runs opVERIFY afterward.
opNumNorEqual	0x9e	✅	Returns 1 if the numbers are not equal, 0 otherwise.
opLessThan	0x9f	✅	Returns 1 if a is less than b, 0 otherwise.
opGreaterThan	0xa0	✅	Returns 1 if a is greater than b, 0 otherwise.
opLessThanOrEqual	0xa1	✅	Returns 1 if a is less than or equal to b, 0 otherwise.
opGreaterThanOrEqual	0xa2	✅	Returns 1 if a is greater than or equal to b, 0 otherwise.
opMin	0xa3	✅	Returns the smaller of a and b.
opMax	0xa4	✅	Returns the larger of a and b.
opWithin	0xa5	✅	Returns 1 if x is within the specified range (left-inclusive), 0 otherwise.
opRipeMd160	0xa6	✅	The input is hashed using RIPEMD-160.
opSha1	0xa7	✅	The input is hashed using SHA-1.
opSha256	0xa8	✅	The input is hashed using SHA-256.
opHash160	0xa9	✅	The input is hashed twice: first with SHA-256 and then with RIPEMD-160.
opHash256	0xaa	❌	The input is hashed two times with SHA-256.
opCodeSeparator	0xab	❌	All of the signature checking words will only match signatures to the data after the most recently-executed opCODESEPARATOR.
opCheckSig	0xac	✅	The entire transaction's outputs, inputs, and script are hashed. The signature used by opCHECKSIG must be a valid signature for this hash and public key. If it is, 1 is returned, 0 otherwise.
opCheckSigVerify	0xad	❌	Same as opCHECKSIG, but opVERIFY is executed afterward.
opCheckMultiSig	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.
opCheckMultiSigVerify	0xaf	❌	Same as opCHECKMULTISIG, but opVERIFY is executed afterward.
opNop1	0xb0	❌	The word is ignored. Does not mark transaction as invalid.
opCheckLockTimeVerify	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 opNOP was executed.
opCheckSequenceVerify	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.
opNop4-opNop10	0xb3-0xb9	❌	The word is ignored. Does not mark transaction as invalid.
opCheckSigAdd	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.

Contributors ✨

Thanks goes to these wonderful people (emoji key):

A₿del ∞/21M 🐺 - 🐱 💻 🤔 🧑‍🏫 📆 🔬 👀	lanaivina 💻	Timothée Delabrouille 💻	okhai 💻	Supreme Labs 💻	Varun Doshi 💻
Add your contributions

This project follows the all-contributors specification. Contributions of any kind welcome!