Crate blk_reader 

Fast reader for Bitcoin Core blk*.dat files.

Reads raw block data directly from Bitcoin Core’s block storage, using the LevelDB index to locate blocks by height. Automatically detects and decodes the XOR encoding introduced in Bitcoin Core 28.0.

Quick start

use blk_reader::{BlockIterator, BlkReaderConfig};
use std::path::PathBuf;

let config = BlkReaderConfig {
    blocks_dir: PathBuf::from("/home/user/.bitcoin/blocks"),
    index_dir:  PathBuf::from("/home/user/.bitcoin/blocks/index"),
    start_height: 0,
    end_height: 100,
    ..Default::default()
};

for result in BlockIterator::new(config).unwrap() {
    let block = result.unwrap();
    println!("height={} size={} bytes", block.height, block.data.len());
}

XOR decoding

Bitcoin Core 28.0 introduced XOR encoding of blk*.dat files to prevent false-positive virus scanner alerts. The key is stored in blocks/xor.dat. This crate detects the file automatically — no configuration needed.

Reading a single block

If you already know the file index and byte offset (e.g. from your own LevelDB query), use BlkReader directly:

use blk_reader::BlkReader;
use std::path::PathBuf;

let mut reader = BlkReader::new(
    PathBuf::from("/home/user/.bitcoin/blocks"),
    8 * 1024 * 1024, // read buffer
);
// Genesis block: file 0, data offset 8
let raw = reader.read_block_at(0, 8).unwrap();
assert_eq!(raw.len(), 285);

Structs

BlkReader

Low-level reader for Bitcoin Core blk*.dat files.

BlkReaderConfig

Configuration for BlockIterator.

BlockIndexEntry

Represents a CDiskBlockIndex entry from Bitcoin Core.

BlockIterator

Height-ordered iterator over raw Bitcoin blocks.

IndexReader

RawBlock

A raw block returned by BlockIterator.

Enums

BlkReaderError