Sigelith Backup — versioned backups that keep your proofs.
Dated, optionally encrypted backups of your folders on an external drive — browse any version and restore just what you need.
Windows 10 (22H2) or Windows 11, 64-bit. Interface in 11 languages. Version history saves space on NTFS drives; on exFAT or FAT32 every version is a full copy.
Sigelith Desktop
What it does
Sigelith Backup backs up the folders you choose — documents, photos, projects — to an external drive or another folder. Every run creates a complete, dated version; unchanged files are linked instead of copied, so the history takes only as much space as what actually changed. Moved or renamed folders aren't copied again, and for very large files only the changed parts are written. A five-step wizard sets everything up and shows the outcome before anything is copied. You can browse any version like a folder, see in which versions a file changed, and restore a single file or everything. Backups can be encrypted, run on a schedule or when the drive is plugged in, and pause to ask you when many files suddenly look encrypted. The drive carries a note and a small script for recovering your files without the program. No account, no ads, no telemetry.
- Complete dated versions; unchanged files take no extra space on NTFS drives.
- Moved or renamed folders aren't copied again; large files save only changed parts.
- Browse any version like a folder and see in which versions a file changed.
- Restore everything, a single folder, or files to their original locations.
- Optional AES-256-GCM encryption, with the key derived from your password (Argon2id).
- Automatic backups: daily at a set time, live — a few minutes after each change — or whenever the backup drive is connected.
- Pauses and asks you first when many files suddenly look encrypted.
Screenshots
Back up your proofs — Sigelith Backup
A Sigelith proof holds only the SHA-256 of your document, so it is only useful together with the exact bytes that were stamped. With “Protect Sigelith evidence” turned on, Sigelith Backup backs up your Sigelith Desktop data folder, including the stamp history, and keeps each stamped document exactly as it was stamped, checked against its hash, together with its .beatproof file, in a separate “Sigelith Evidence” store that retention never cleans up. If a document was edited after stamping, the program recovers the stamped version from older backups where it can — the proof itself is always kept — and the “Sigelith evidence” window checks proofs offline and restores documents.
Each backup version can also get a Sigelith timestamp: only the SHA-256 hash of the version’s seal — a short statement with the hash of its file list and the root of its file tree — is sent, and the weekly signature is checked with a key built into the program.
Sigelith inside your backups
Four features that tie your backups to Sigelith. None of them puts your files on a server — Sigelith only ever sees hashes.
A time proof for any file
Any file in a sealed backup version can get its own small proof file and a PDF certificate: this file was in the backup at that moment. The proof reveals nothing about the other files and can be checked in Sigelith Desktop or at sigelith.org/verify/.
A backup that can't be swapped quietly
The content audit reads every file of a version back from the drive and compares it with the hashes sealed in the public Sigelith log — not with the file list stored next to them, which could be forged as well. “Last untouched” points to the newest version that still matches its seal.
Hand over a file with proof of delivery
Pick any version of a file — say, a contract as it was in March — and send it with Sigelith Handover in Sigelith Desktop. The recipient confirms receipt with their own key, and the moment of delivery is recorded in the public log. This needs Sigelith Desktop 3.0.1 or later.
A time capsule inside your backup
Seal a folder until a date you choose. Any two of three parts open it: the drand round for that moment, the Sigelith key server’s share, which we release only after the date — our policy, not a cryptographic limit — and the recovery code, which is saved next to the capsule. Whoever holds the backup therefore has the code too, and needs only us to break that policy to open it early. The capsule stays in your backup, not on a server, and sigelith.org/capsule/ opens it after the date.
System requirements
Windows 10 (22H2) or Windows 11, 64-bit. Interface in 11 languages. Version history saves space on NTFS drives; on exFAT or FAT32 every version is a full copy.
Privacy
Nothing is sent over the internet unless you turn on one of two optional features: an off-site copy, encrypted on your computer and sent directly to your own S3-compatible storage, or Sigelith timestamps, which send only the SHA-256 hash of a backup version's seal to sigelith.org. “Protect Sigelith evidence” works entirely on your computer.
Sigelith Desktop — proofs on your own computer.
Timestamp files without uploading them, verify any proof offline, watch the public log’s independent witnesses — and hand over files with proof of delivery. Free, no account, open source.
Sigelith Backup is free and open source (GPL-3.0). No account, no ads, no telemetry.