ZiglyNode - Zig Lyght Node

A Bitcoin light client with minimal dependencies written in Zig

• I like handmade software
• I like Bitcoin
• I like Zig

Build Requirements

• Currently building with Zig 0.14.1

  • See https://ziglang.org/download/

• Windows 11 and Ubuntu WSL are usually tested.

• Before compiling, add a file called .privkey to the src directory.

  • echo 0a1a2a3a4a0a1a2a3a4a0a1a2a3a4a0a1a2a3a4a0a1a2a3a4a0a1a2a3a4a0a1a > src/.privkey

This file should contain hex characters representing the private key to use when signing transactions. DO NOT USE REAL WALLET INFORMATION WITH THIS SOFTWARE.

Features

All features here are implemented (at least almost) from scratch. Using only the standard library and an external RIPEMD hash function.

• Amateur cryptography (ECDSA)
• Bitcoin primitives (Address, Transaction, Block) with serialization
• Signing valid transactions (see https://mempool.space/signet/tx/d5cf8e758abc178121736c9cbb0defe075ef50da4dfb4e736b19f2a2ff66dd14)
• Basic Script interpreter (tested P2PK, P2PKH and P2WPKH)
• Ability to communicate with the Bitcoin network
  • Handshake with other peers
  • Get block headers, check they are valid and write/load them on disk
  • Get neighbour peers to discover the network
• Multi-threaded handshakes for speed

Screenshots

Example of current output:

> zig build run
info: loading block headers from path/to/ZiglyNode/blockheaders.dat

Your address is mwWdV8mUAE2rQugQLtRJdrqxi3rf4R3xbq

################################################

Hello dear hodler, tell me what can I do for you
1. List peers (interact)
2. Connect to a new peer
3. View blockchain state
4. Sign a transaction
5. Exit

3

=== Blockchain State ===
Block headers count: 66001
Latest block hash: 00000000071d7e8a0f4895e60c1073df9311d65a85244be1ee6369c9506281af
========================

2

Enter the IPv4 or IPv6 [without port] [default=127.0.0.1]: 
Enter the port [numeric, default=8333]: 

Connection established successfully with
Peer ID: 1
IP: 127.0.0.1:8333

i 1

What do you want to do?
1. disconnect from peer
2. ask for block headers
3. ask for new peers and connect
2
Requesting for block headers...
Unexpected and unsupported command received
Unexpected and unsupported command received
2000 new blocks received!

3

=== Blockchain State ===
Block headers count: 68001
Latest block hash: 0000000000d991791fdfdbccbbc2a73d2f86ccf78e2d0a7ce7675f40b5986b3e
========================

i 1

What do you want to do?
1. disconnect from peer
2. ask for block headers
3. ask for new peers and connect
3
info: Requesting for new peers and connecting...
Unexpected and unsupported command received
info: Connecting to [2a01:4f8:c2c:5011::1]:8333...
info: Connecting to 62.171.183.58:8333...
info: Connecting to 34.97.22.229:8333...
info: Connecting to 85.158.1.212:8333...
info: Connecting to 99.8.113.140:8333...
info: Connecting to 174.161.123.250:8333...
info: Connecting to 109.87.166.145:8333...
info: Connecting to 76.28.244.128:8333...
info: Connected to [2a01:4f8:c2c:5011::1]:8333
info: Connected to 62.171.183.58:8333
info: Connected to 109.87.166.145:8333
info: Connected to 34.97.22.229:8333
info: Connection to 85.158.1.212:8333 failed: Timeout
info: Connection to 99.8.113.140:8333 failed: Timeout
info: Connection to 76.28.244.128:8333 failed: Timeout
info: Connection to 174.161.123.250:8333 failed: Timeout
info: Connected to 4 new peers

################################################

Hello dear hodler, tell me what can I do for you
1. List peers (interact)
2. Connect to a new peer
3. View blockchain state
4. Sign a transaction
5. Exit

1

======== Peer list ========

1: 127.0.0.1:8333 | /Satoshi:27.1.0/Knots:20240801

2: 3.143.194.71:8333 | /Satoshi:27.1.0/

3: 86.104.228.24:8333 | /Satoshi:27.0.0/

4: 170.253.31.42:8333 | /Satoshi:28.1.0/

5: 66.163.223.69:8333 | /Satoshi:27.1.0/

6: [2a02:22a0:bbb3:dc10:50e1:57ff:fe70:9492]:8333 | /Satoshi:29.0.0/

===========================

Type 'i' followed by a number to interact with a peer (ex.: 'i 2')

5
info: saving data on disk...

TODO

• Networking improvements
  • Concurrent connect calls
  • Consume next address immediately after a connection fails
  • Event loop to answer spontaneous messages (not sure we need this)
• Continous requests (enter synchronization mode)
• P2SH
• Check difficulty when receiving block headers
• SPV
• SegWit

Issues:

• We can't seem to receive blocks from /Satoshi:25.1.0/
  • Minimum version we know that works is /Satoshi:27.0.0/