Quick Guide: Building Checksums & PGP-Signed Releases for Community Mod Torrents

Quick Guide: Building Checksums & PGP-Signed Releases for Community Mod Torrents

Hook: Tired of users asking whether your mod, patch or voice pack is legitimate — or watching seeders fall off because people fear malware? For community release managers, the fastest path to trust is simple: publish cryptographic checksums and a verified PGP-signed release. This guide gives a practical, modern 2026 workflow to create, sign, publish and verify torrent releases so users can trust files and you can reduce support overhead.

Why this matters in 2026

Late 2024–2025 saw a notable rise in supply-chain tampering and fake mod repacks. By early 2026, communities are demanding stronger provenance for downloads: reproducible hashes, verifiable signatures, and clear publishing rules. Release managers who sign their torrents and offer signed checksum manifests reduce user friction, improve seeding confidence and make it far harder for attackers to impersonate an official release.

Big-picture workflow (what you’ll do)

1. Prepare your release files (mod, patch, installer, changelog).
2. Generate strong checksums (SHA-256 or SHA-512) for every file.
3. Create the .torrent and/or magnet link.
4. Sign both the checksums file and the .torrent/magnet using your PGP key.
5. Publish: torrent, signed checksums, signed .torrent/.magnet, public key/fingerprint.
6. Provide clear verification steps for users and seed from trusted machines.

Core principles and best practices

• Sign everything a user can download: archive, installer, checksums file, .torrent and a text file containing the magnet link.
• Use modern keys: Ed25519 (or RSA 4096 if legacy required). Keep a short-lived online subkey; keep the master key offline.
• Publish fingerprints out-of-band: put the fingerprint on your project page, GitHub, Nexus/Discord profile and at least one social account.
• Use detached armored signatures: .asc or .sig files make automated verification easy.
• Provide verification instructions: include commands for Linux, macOS and Windows — most users will copy-paste them.
• Seed from a dedicated trusted environment: seed from a seedbox or air-gapped machine when possible; reduce attack surface.

Step-by-step: Create checksums

Checksums are the simplest integrity proof: they allow users to confirm the bits they downloaded match what you published. Use SHA-256 (minimum) or SHA-512 if you want to be extra cautious.

Linux / macOS (bash)

# In your release folder
sha256sum * > checksums-sha256.txt
# macOS (if sha256sum not installed)
shasum -a 256 * > checksums-sha256.txt

Windows (PowerShell)

# In PowerShell
Get-ChildItem -File | ForEach-Object { $h = Get-FileHash -Path $_.FullName -Algorithm SHA256; "$($h.Hash)  $($_.Name)" } | Out-File -Encoding ASCII checksums-sha256.txt

Keep the checksums file format simple: one line per file with checksum and filename. This format is directly consumable by standard tools (sha256sum -c on Linux).

Step-by-step: Create and sign your PGP key (practical setup)

2026 recommendation: create an Ed25519 primary key with a non-exportable offline master and an online subkey for signing. If you prefer classic RSA, use 4096 bits and similar offline/online separation.

Generate a key (simple)

# Quick: creates an Ed25519 signing key
gpg --quick-generate-key "Release Name <you@example.com>" ed25519 sign 0

# Or use the interactive full generation for subkeys & expiry
gpg --full-generate-key

Export your public key & fingerprint

# Export armored public key
gpg --armor --export you@example.com > pubkey.asc

# Show fingerprint
gpg --fingerprint you@example.com

Important: generate a revocation certificate immediately and store it offline:

gpg --output revoke.asc --gen-revoke you@example.com
# Keep revoke.asc offline in case the key is compromised

Signing your release files

Sign both the checksums manifest and the .torrent (or magnet text). Keep signatures detached and ASCII-armored so they’re easy to distribute.

Sign checksums (detached)

gpg --armor --detach-sign checksums-sha256.txt
# Produces checksums-sha256.txt.asc (detached signature)

# Optionally create a clear-signed file so users can read checksums without GPG
gpg --clearsign checksums-sha256.txt
# Produces checksums-sha256.txt.asc (cleartext signature)

Sign a .torrent

# Create your .torrent with your client (qBittorrent/rtorrent/etc.), then:
gpg --armor --detach-sign MyMod_v1.2.3.torrent
# Produces MyMod_v1.2.3.torrent.asc

# For magnet-only releases, write the magnet to a text file and sign it
echo "magnet:?xt=urn:btih:YOUR_INFO_HASH&dn=MyMod_v1.2.3" > magnet.txt
gpg --armor --detach-sign magnet.txt

Include the signature files alongside the .torrent or magnet on your download page. Users should never trust a torrent unless the .torrent/.magnet file has a valid detached signature created by your key.

Publishing and communicating authenticity

Signing is only useful if users can find and verify your public key and fingerprint. Publish them in multiple, verifiable places.

• Post pubkey.asc on your official release page and GitHub repository.
• Show the key fingerprint in text on your project’s main page and in pinned social posts.
• Pin the pubkey to at least one third-party service (GitHub, GitLab or IPFS) to make tampering harder.
• Include a short verification guide on the release page (copy-and-paste commands for the three major OSes).

Tip: A fingerprint posted on your Discord, GitHub and a pinned tweet offers three independent channels for TOFU (trust on first use) verification. For larger communities, consider a dedicated keyserver or publishing a public key signed by multiple maintainers.

User verification steps (what your users will do)

Provide these exact commands on your release page so users can verify downloads before running them. Keep commands copy-paste friendly.

1) Import your public key (one-time)

# Import the published ASCII key
gpg --import pubkey.asc

# Verify the fingerprint matches what you published (show fingerprint)
gpg --fingerprint you@example.com

2) Verify the checksums signature and then check files

# Verify signature
gpg --verify checksums-sha256.txt.asc checksums-sha256.txt

# Verify file checksums (Linux/macOS)
sha256sum -c checksums-sha256.txt

# Windows (PowerShell):
Get-Content checksums-sha256.txt | ForEach-Object { $parts = $_ -split "\s+"; $hash = $parts[0]; $file = $parts[-1]; (Get-FileHash -Algorithm SHA256 $file).Hash -eq $hash }

3) Verify the .torrent or magnet signature

# For torrent
gpg --verify MyMod_v1.2.3.torrent.asc MyMod_v1.2.3.torrent

# For magnet (magnet.txt and magnet.txt.asc)
gpg --verify magnet.txt.asc magnet.txt

If GPG reports a valid signature and the fingerprint matches the one you published, the file is authentic and hasn’t been tampered with since you signed it.

Automation: example release script (Linux)

Automate checksum generation and signing in a release script you run from your build/packaging server:

#!/bin/bash
set -e
RELEASE_DIR=release_v1.2.3
cd "$RELEASE_DIR"
# 1) checksums
sha256sum * > checksums-sha256.txt
# 2) sign checksums (detached)
gpg --armor --detach-sign checksums-sha256.txt
# 3) create torrent with your client (example: mktorrent)
# mktorrent -a  -o MyMod_v1.2.3.torrent *
# 4) sign torrent
gpg --armor --detach-sign MyMod_v1.2.3.torrent
# 5) bundle artifacts
mkdir -p ../out
cp *.torrent *.asc checksums-sha256.txt* ../out/

Run signing on a machine with the signing subkey available. For maximum security, keep the master key offline and transfer files securely to an air-gapped signing machine when needed.

Advanced topics & future-proofing (2026 outlook)

Long-term authenticity planning in 2026 means thinking beyond single-key setups:

• Subkeys & rotation: use an online subkey for daily signing and rotate it periodically. Keep the primary key offline.
• Hybrid signatures: as post-quantum (PQC) signatures start to appear in tooling, plan for hybrid signatures (classical + PQC) — but only after tooling stabilizes.
• Reproducible packaging: when possible, provide reproducible build logs and hashes so independent parties can reproduce and verify repacks.
• Decentralized mirrors: pin signed artifacts to IPFS or Arweave to provide immutable mirrors and defend against takedown tampering.

Seeding security & operational tips

Release managers often seed to keep healthy swarms. Reduce risk with these practical steps:

• Seed from a dedicated seedbox or VM that has only the signed release files; avoid seeding from a personal desktop with unrelated files.
• Use a VPN for seeding if local laws or privacy concerns make you uncomfortable; for accountability, document the IP/fingerprint you seed from.
• Never include private keys on seeding machines. Keep signatures pre-generated on a secure system.
• Provide multiple trackers or use DHT and PEX. For critical releases, offer a direct HTTP mirror (signed) as a fallback for users who won't torrent.

Common pitfalls & how to avoid them

• Missing fingerprint: if you publish a key but don’t post the fingerprint on other channels, users can’t easily verify it — always publish the fingerprint separately.
• Unsigned torrents: unsigned .torrent files are the top vector for spoofed releases. Make torrent signatures mandatory for official downloads.
• Leaked signing keys: never store your primary keys on the same machine you use for general browsing or torrenting.
• Weak hashes: MD5 and SHA-1 are deprecated; use SHA-256 or SHA-512 (SHA-256 covers almost all use cases).

Example release checklist for every mod/patch/voice pack

• Prepare final release files and changelog.
• Generate checksums (sha256) and create checksums-sha256.txt.
• Sign checksums (detached and/or clearsign).
• Create .torrent and/or magnet.txt.
• Sign .torrent and/or magnet.txt (detached).
• Export current public key and publish pubkey.asc and fingerprint.
• Upload artifacts to torrent site & mirror; include signatures and verification instructions.
• Seed from a trusted environment and announce fingerprint in release notes.

Actionable takeaways

• Today: generate a PGP key and publish its fingerprint on your project page.
• This release: add signed checksums and sign your .torrent/.magnet before you upload.
• Ongoing: automate signing in your release pipeline and store a revocation certificate offline.

Security is trust expressed in bits. Signed checksums and signed torrents are the clearest, lowest-friction way to give your community confidence in 2026 and beyond.

Final notes: legal & community etiquette

Signing does not remove legal responsibility. Ensure your releases respect copyright, licenses and platform rules. When possible, provide legal alternatives and links to store pages so users can support original creators. Signing is about integrity and safety—not bypassing legal obligations.

Call to action

Ready to make your next release trustable? Start by creating an Ed25519 key and publishing its fingerprint. Implement the checklist above for one release and watch user trust and seeder counts improve. If you want a ready-to-run script or a 1-page verification card to include on your release page, export your public key fingerprint below or join the discussion in your project's channel and share your release plan — I'll help you review it.

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