Cryptographically verified UTXO snapshot with PAR2 self-repairing error correction. One command to verify, decompress, and load.
Block 937,817 — February 2026 — Bitcoin Core v29Initial Block Download (IBD) syncs every block from genesis. On consumer hardware, that takes days. Many users give up before their node finishes syncing.
8.8 GB → 7.9 GB. Zstandard decompresses at ~1.5 GB/s with built-in frame checksums.
~10% compression ratio with frame-level integrity (xxhash64 per frame). Streaming decompression uses constant memory regardless of file size. 10–50x faster than gzip, 30–100x faster than xz at decompression.
SHA-256 + SHA-512 for both compressed and raw files. Two independent algorithms, cross-verified.
4 total hashes verified: 2 algorithms × 2 files (compressed + raw).
Different internal structures defend against length-extension and
algorithm-specific attacks. Verify manually:
shasum -a 256 -c SHA256SUMS
5% Reed-Solomon redundancy. Detects and repairs up to ~400 MB of file corruption without re-downloading.
Based on Reed-Solomon error correction — the same math behind CDs and QR codes. Repairs bit-rot, truncation, and bad sectors. 403 MB of recovery data protects the full 8 GB file. par2cmdline is open-source. First UTXO snapshot project to include PAR2.
Automated installer that verifies integrity, decompresses, configures Bitcoin Core, and loads the snapshot.
./INSTALL.sh in Terminal, or double-click
Install.command.
Auto-detects shasum, zstd,
par2, bitcoin-cli.
./INSTALL.sh in any terminal, or double-click
Install.desktop.
Ubuntu, Fedora, Debian, Arch — anywhere bash runs.
.\INSTALL.ps1 in PowerShell —
no extra dependencies beyond zstd.
Or double-click INSTALL.bat to auto-launch via WSL or Git Bash.
--non-interactive for scripted and CI installs.
We'll customize the instructions for you.
Download from bitcoincore.org — available for macOS, Linux, and Windows.
From the Internet Archive page, or use the direct links below.
# macOS brew install zstd par2 # Linux (Debian/Ubuntu) sudo apt install zstd par2 # Windows (via Chocolatey or Scoop) choco install zstandard # or: scoop install zstd
chmod +x verify-and-load.sh ./verify-and-load.sh
It verifies PAR2 integrity, checks SHA-256, decompresses, and optionally loads into Bitcoin Core.
Add the snapshot entry to Bitcoin Core and rebuild. See details below.
The script asks: Pruned (~10 GB) or Full archival (~600 GB)? Pruned is recommended for most users — same security, fraction of the disk.
Bitcoin Core is immediately usable at block 937,817. Background validation completes automatically.
Permanently hosted on the Internet Archive — free, reliable, no seeders required.
| File | Description | Size |
|---|---|---|
| utxo-937817.dat.zst | Compressed UTXO snapshot | 7.9 GB |
| utxo-937817.dat.zst.par2 | PAR2 index | 39 KB |
| utxo-937817.dat.zst.vol000+100.par2 | PAR2 recovery blocks | 403 MB |
| SHA256SUMS | SHA-256 checksums | 168 B |
| SHA512SUMS | SHA-512 checksums | 296 B |
| verify-and-load.sh | One-command verify + load script | 12 KB |
Add this entry to src/kernel/chainparams.cpp inside
CMainParams, in the m_assumeutxo_data map
(after the 910,000 entry):
{
.height = 937'817,
.hash_serialized = AssumeutxoHash{uint256{
"1e958331afe8162df7d8779e4a96e06bd3c1517c168f271c44e327fc040fda95"
}},
.m_chain_tx_count = 1314106044,
.blockhash = consteval_ctor(uint256{
"000000000000000000009025a9fdaa6b039c0df253b46331bdc12e7165c6a819"
}),
}
Then rebuild:
cmake --build build -j$(nproc)
Anyone with a fully synced node at or past block 937,817 can independently verify:
bitcoin-cli gettxoutsetinfo muhash \ "000000000000000000009025a9fdaa6b039c0df253b46331bdc12e7165c6a819" # Expected: # "hash_serialized_3": "1e958331afe8162df7d8779e4a96e06bd3c1517c168f271c44e327fc040fda95" # "txouts": 164547146
After loading, Bitcoin Core validates all historical blocks in the background. If any discrepancy is found, the snapshot is automatically rejected.
Download the whitepaper PDF and upload it to Claude Code, Codex, or any AI coding assistant. Say:
5ff2b5d51604439f3e3cd9c24f9fd27be7297279563a5889033661099d996d50 utxo-937817.dat
b6636f1a3cdabfe2f2fa67a2cee07906714a880c680091b916acd40855ae952f utxo-937817.dat.zst
87002076f5dd80564657a1122c3de16e79353da54b7d1455605ccbaa4b049b0153dd01686bd396b7b5d05d6fa3b4bb4c02c370bb19a9dea78917dad48a7dbc3b utxo-937817.dat
cf5f672600b89b4f430969da05af22fc70c510ebd84459e310008a9ac2aed6911100a0ca9eba33d9081ae1400255757abc08fc88ff2cea34ace58e46f648ce0f utxo-937817.dat.zst
shasum -a 256 -c SHA256SUMS shasum -a 512 -c SHA512SUMS
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