Glossary

Terms that appear in the program and in this manual, in alphabetical order.

age: an open file encryption format used by an encrypted archive disc. The age program for Windows, Linux and macOS is on every such disc (see “Recording an encrypted disc”).

Archive (for a disc): chosen files and folders prepared for recording on a disc, with their own Sigelith seal (see “Recording selected files and folders”).

Archive disc: a DVD, BD-R, BDXL or M-DISC disc recorded by the program, which describes itself and can also be read without the program (see “Which discs and which burner to choose”).

Backup folder: the folder chosen in the “Where we write” box. It holds the versions, the table of contents and the program's files. For restoring and checking, you always choose this main folder, not a dated version folder.

Backup password, disc password, off-site backup password: three separate passwords for three kinds of backup. None of them can be recovered or reset (see “I don't remember the backup or disc password”).

BeatTime: the time the program uses to label backup versions, for example @487. A day has 1000 beats counted from midnight UTC, so the same number means the same moment everywhere in the world.

Bitcoin anchor: the record of the week's root in the Bitcoin blockchain, the last step of a complete seal (see “A seal or timestamp is waiting”).

Bucket: a place for data in an S3-compatible service (see “Setting up an off-site backup”).

Checksum (SHA-256): a short “fingerprint” of a file's content. The smallest change in the content gives a different checksum, so checksums tell the program whether a file is intact.

Content audit: a check that the files of a version match its seal in the Sigelith public log (see “Checking that nobody has tampered with files in the backup”).

Disc card: a printout or PDF file with the password of an encrypted disc and short instructions for reading it. Without it you cannot read the encrypted disc (see “Recording an encrypted disc”).

Disc register: the list of archive discs: what is on which disc, where it is kept and when to check it (see “The disc register: where discs are kept and finding files”).

drand: a public network that announces random values at set moments. A time capsule uses its round from the moment of opening (see “Sealing a folder until a chosen date”).

Encryption: storing the backup files in a form that cannot be read without the password. The program uses AES-256-GCM and derives the key from the password with Argon2id. Encrypted files end in .cvlt (see “Encrypting a backup”).

Exclusion: a pattern of files and folders that the backup leaves out, for example *.tmp (see “Leaving out unneeded files”).

File proof: a file ending in .sigelith-proof that confirms that one file from the backup already existed at the moment the version was timestamped, without revealing any other files (see “Creating a time proof for a single file”).

Hard link: the way the NTFS file system shows the same file in several folders without taking up space a second time. Thanks to this, dated versions take up only as much space as has changed. The exFAT and FAT32 file systems cannot do this.

Incremental storage: the way large files, 256 MB and more, are stored. The file lies in the backup as a recipe and parts, and the next version stores only the changed parts (see “Creating a backup without the wizard”).

ISO image: the whole content of a disc in a single file, to be recorded later or with another program (see “Creating only an ISO image”).

Last untouched: the newest backup version whose files all match its seal (see “Checking that nobody has tampered with files in the backup”).

Live backup: a schedule with which changes reach the backup a few minutes after a file is saved (see “Turning on live backup”).

Mirror copy: a backup layout with one folder kept in step with the source, without earlier versions of files (see “Creating a backup without the wizard”).

Off-site backup: a second, encrypted backup in an S3-compatible online storage service (see “Setting up an off-site backup”).

Program log: the record of the course of operations, with the exact causes of errors (see “Where to find details: the program log”).

Public log of Sigelith: the register of timestamps kept by Sigelith. Its state is confirmed by independent witnesses and the Bitcoin blockchain, so an entry cannot be changed without anyone noticing.

Ransomware: malware that encrypts files and demands a ransom (see “The backup stopped because many files look encrypted”).

Recovery code: one of the three parts of a time capsule's key, saved next to the capsule (see “Sealing a folder until a chosen date”).

Recovery data (PAR2): additional data on a disc from which a damaged part of it can be rebuilt, up to 15% of the data by default (see “What is on a recorded disc and why it takes more space”).

Retention rules: the setting for how many backup versions to keep; the program deletes the surplus after a successful backup (see “Choosing how many versions to keep”).

Schedule: the template setting for when the backup starts by itself. A backup started by the schedule is a scheduled backup (see “Setting up automatic backups”).

Sigelith evidence: the “Sigelith Evidence” folder in the backup, with documents stamped in Sigelith Desktop and their .beatproof files (see “Protecting Sigelith Desktop evidence”).

Sigelith seal (timestamp): proof that a backup version or an archive, in exactly this shape, already existed at the moment it was timestamped. Only a hash goes to Sigelith, from which neither the names nor the content of files can be reconstructed (see “Timestamping backup versions with Sigelith”).

Snapshot: the state of the files from one upload of the off-site backup (see “Setting up an off-site backup”).

Table of contents (of a backup): a program file in the backup folder with the list of files, their checksums and where they are stored. Without it the program can still read the backup, recognising files by their content.

Template: saved backup settings, run with one click or on a schedule (see “Saving settings as a template”).

Time capsule: a chosen folder sealed until a moment you specify, kept in the backup (see “Sealing a folder until a chosen date”).

Top-up of changes made during the backup: once the backup is finished, the program adds to the same version the files that changed while it was being copied (see “Creating a backup without the wizard”).

Trial restore: restoring a random sample of files in a temporary folder and comparing them with the originals (see “Trial restore”).

Unfinished version: a version from a backup that was interrupted or finished with errors. The program offers to finish it (see “Finishing an interrupted backup”).

UTC: Coordinated Universal Time. The dates in the names of backup versions are UTC dates.

Version (dated): a folder with a date and time in the backup folder: the complete state of the files from one backup run (see “Creating a backup without the wizard”).

Week's signature: the Sigelith signature over all timestamps from a given week, made after the week closes on Monday at 00:00 UTC (see “A seal or timestamp is waiting”).

Windows Credential Manager: the Windows password store tied to your account. The program remembers passwords and access details there (see “Deleting remembered passwords”).