zupt/doc/zupt.1

.\" SPDX-License-Identifier: AGPL-3.0-or-later
.\" Copyright (c) 2025-2026 Cristian Cezar Moisés
.TH ZUPT 1 "2026-08-31" "ZUPT 5.2.7" "User Commands"
.
.SH NAME
zupt \- source-built backup compression and authenticated-encryption utility
.
.SH SYNOPSIS
.B zupt compress
.RI [ options ]
.I output.zupt input...
.br
.B zupt extract
.RI [ options ]
.I archive.zupt
.br
.B zupt list
.RI [ options ]
.I archive.zupt
.br
.B zupt test
.RI [ options ]
.I archive.zupt
.br
.B zupt info
.I archive.zupt
.br
.B zupt bench
.RB [ --compare ]
.I input...
.br
.B zupt disk backup
.RI [ options ]
.I output.zupt device-or-file
.br
.B zupt disk restore
.RI [ options ]
.I archive.zupt target-device-or-file
.br
.B zupt keygen
.RI [ key-options ]
.B -o
.I output
.br
.B zupt
.RB { help | --help | -h | version | --version | -V }
.
.SH DESCRIPTION
.B zupt
creates self-contained backup archives with the historical
.B .zupt
extension. Version 5.2.2 restores the original product name, ZUPT, and the
primary installed command is
.BR zupt .
The archive extension and
.B ZUPT
format magic, codec identifiers, and archive compatibility remain unchanged.
.
.PP
Plain archives provide compression checksums for accidental-corruption
detection. They do not provide cryptographic authentication against an attacker
who can rewrite an archive. Encrypted archives use AES-256-CTR with
HMAC-SHA256 and authenticate current per-block framing, logical frame position,
and archive metadata. The validating read paths require an archive-integrity
trailer by default; a no-trailer archive fails closed unless the caller selects
the explicit trusted-legacy override described below.
See
.B SECURITY.md
and
.B THREAT_MODEL.md
for the exact boundary and historical-format limitations.
.
.PP
The bundled compression codec is VaptVupt codec 2.65.3.
Automatic codec selection uses VaptVupt where the supported AVX2 or NEON path
is available and uses the portable LZHP codec otherwise. Use a codec-selection
option only when a specific choice is required.
.
.PP
The renamed-era
.B vaptvupt
command is an optional compatibility alias and is not installed by default.
Distribution packages, including the openSUSE main package, expose
.B zupt
as the canonical command.
.
.PP
Git and the upstream source tarball are source-only. Separately built CLI DEB,
binary RPM, SRPM, notice-bearing Linux tar.xz, Windows ZIP, and macOS DMG assets
may be published from the immutable tag only after their target-specific gates
pass; they never enter Git or the source tarball. An AppImage is not promoted
for 5.2.7; neither are AppDir/Flatpak bundles, GUI platform installers, or bare
Linux/Windows executables. The Python/Qt frontend remains available as source;
its gated architecture-independent DEB, noarch/source RPM, and source-only
portable ZIP are included in the release claim. The portable ZIP contains no
Python, Qt, CLI, or compiled runtime. Windows and macOS artifacts remain
CLI-only.
.
.SH COMMANDS
.TP
.BR compress , " c"
Create an archive from one or more files or directories. Directories are
traversed recursively. All options must precede
.IR output.zupt .
A literal input name beginning with a hyphen can follow a
.B --
separator after the output name.
.
.TP
.BR extract , " x"
Extract regular-file contents below the current directory or the directory
selected by
.BR -o .
Entry names are validated and resolved below a pinned destination. Existing
destination files are not overwritten. Decoded data is published from a
private temporary file only after its expected size and checksum are verified.
ZUPT does not restore ownership, ACLs, extended attributes, original mode,
or modification time.
.
.TP
.BR list , " l"
Open and verify the archive as required, then print its format, block and
protection flags followed by each entry's path, original size, compressed size,
and compression ratio. No file is extracted.
.
.TP
.BR test , " t"
Decode and verify the archive without writing extracted files. Exit status is
nonzero on an authentication, integrity, format, or I/O failure.
.
.TP
.BR info , " i"
Read non-secret framing metadata without a password or private key. Current
output includes archive size, format version, integrity-trailer type, UUID,
creation timestamp, block count when a footer is found, encryption/PQ mode,
selected global feature flags, and whether a comment is present. This command
does not decrypt, list, or extract entries. It does not validate the trailer or
archive contents: a reported trailer is framing information, and successful
execution is not an integrity result. Its input must still be treated as
untrusted.
.
.TP
.BR bench , " b"
Run the built-in compression-level benchmark on supplied input. With
.BR --compare ,
also compare external compressors available on the host. Results depend on the
input, compiler, CPU, storage, and system load and are not release support
claims.
.
.TP
.B disk backup
Read a device or regular file sequentially and create a sparse-aware archive.
Zero regions are represented without storing their full contents.
.
.TP
.B disk restore
Restore a disk-image archive to a device or regular file. The target is written
destructively; verify both operands and use the least privilege required. The
archive is first copied to a private, auto-deleted scratch file, and validation
and restoration consume that same snapshot before the target is opened. Set
.B ZUPT_TMPDIR
to an existing private scratch directory when needed; an invalid override fails
without fallback. A raw block device is rejected before the first write when
its capacity cannot be determined or is smaller than the restored image.
.
.TP
.B keygen
Generate a native ML-KEM-768 plus X25519 hybrid private key by default. Other
key formats require the matching key-generation option and, for optional SDK or
PQBOX modes, a build with the corresponding system integration enabled.
.
.TP
.BR version , " --version" , " -V"
Print the program, archive-format and codec versions, compiled optional
integrations, runtime CPU acceleration, license scopes, and canonical project
URL.
.
.TP
.BR help , " --help" , " -h"
Print command usage and the options compiled into the program.
.
.SH PASSWORD INPUT
The password options are accepted by
.BR compress ,
.BR extract ,
.BR list ,
.BR test ,
and both
.B disk
subcommands. For
.B compress
and
.BR "disk backup" ,
the interactive form asks for confirmation.
.
.TP
.BR -p " " password , " --password " password
Read a password directly from the next process argument. This is compatible
with older command lines but can expose the password through shell history or
process inspection. Prefer one of the non-argv forms below.
.
.TP
.B --password-prompt
Read the password from the terminal without echo. This explicit form avoids
the optional-argument ambiguity of historical
.BR -p .
On POSIX, handled interruptions restore the terminal settings saved before the
prompt.
.
.TP
.BI --pass-file " file"
Read the first line from
.IR file .
The trailing LF and an optional preceding CR are removed. Empty input, an
embedded NUL, or an overlong password is rejected. Protect the file with
restrictive permissions and remove it securely when it is no longer needed.
.
.TP
.BI --pass-fd " fd"
Read the first line from the inherited numeric file descriptor
.IR fd .
ZUPT duplicates the descriptor for reading and does not close the caller's
original descriptor. The duplicate shares the underlying stream and offset;
buffered input may consume beyond the password line, so dedicate the descriptor
to this read. The same input validation as
.B --pass-file
applies.
.
.SH COMPRESSION OPTIONS
These options are accepted by
.B compress
unless stated otherwise.
.
.TP
.BR -l " " 1..9 , " --level " 1..9
Set the compression level. The default is 7. Automatic block sizes are 128 KiB
for levels 1-2, 1 MiB for levels 3-4, 2 MiB for levels 5-6, 4 MiB for level 7,
and 8 MiB for levels 8-9. Deduplication uses a smaller automatic granularity.
.
.TP
.BR -b " " bytes , " --block " bytes
Set the block size in bytes. Values are constrained to the supported range of
64 KiB through 256 MiB.
.
.TP
.BR -s , " --store"
Store data without compression.
.
.TP
.BR -f , " --fast"
Select the fast LZ codec.
.
.TP
.BR --vv , " --vaptvupt"
Force the bundled VaptVupt LZ plus ANS codec.
.
.TP
.B --lzhp
Force the portable LZHP codec.
.
.TP
.BI --kdf " algorithm"
Select the password KDF. The default source-only build supports and defaults to
.BR pbkdf2 ,
using PBKDF2-SHA256 with 600,000 iterations. A
.B WITH_SDK=1
build additionally supports
.B argon2id
and uses it by default. A build must reject a requested KDF that it cannot
provide rather than silently changing algorithms.
.
.TP
.BR -c " " text , " --comment " text
Store a comment of up to 4095 CLI bytes. In an encrypted archive the comment is
encrypted and authenticated with the archive; in a plain archive it receives
only the plain archive's non-cryptographic integrity treatment.
.
.TP
.BI --comment-file " file"
Read the comment from
.IR file .
Trailing CR/LF characters are removed.
.
.TP
.BR -D , " --dedup"
Enable block-level deduplication. Encrypted deduplicated blocks still use fresh
per-block nonces in current archives. DATA and DEDUP_REF frames are bound to
their logical positions. An authenticated reference also carries the source
position required to authenticate the referenced DATA frame.
.
.TP
.BR -S , " --solid"
Use one solid compression stream. Solid mode is single-threaded.
.
.TP
.BR -y , " --force"
Allow
.B compress
to overwrite an existing output whose name does not end in
.BR .zupt .
This does not relax extraction's no-overwrite policy.
.
.TP
.BR -t " " count , " --threads " count
Set the compression or extraction thread count. Zero selects automatic
detection; explicit values are limited to 64. This option is accepted by
.B compress
and
.BR extract ,
and by disk backup/restore, but not by
.B list
or
.BR test .
.
.TP
.BR -v , " --verbose"
Enable additional progress or diagnostic output where the selected command
implements it. Authentication failures remain intentionally generic unless
verbose diagnostics are requested, reducing the default verbal probe-oracle.
.
.SH POST-QUANTUM OPTIONS
.TP
.BI --pq " key"
Use the native hybrid envelope: ML-KEM-768 plus X25519 with the archive-key
combiner documented in
.BR THREAT_MODEL.md .
Use the recipient public key for creation and the matching private key for
reading. This is the recommended native PQ mode.
.
.TP
.BI --pq-only " key"
Use native ML-KEM-768 without the X25519 hedge. Choose it only when a policy
requires a single post-quantum KEM. Its keys are generated with
.BR "zupt keygen --pq-only" .
.
.TP
.BI --pq-sdk " key"
Use the optional system
.B libvuptsdk
integration. This option is unavailable unless ZUPT was built with
.BR WITH_SDK=1 .
It is not enabled by the default source-only distribution build.
.
.TP
.BI --pq-box " key"
Use the optional system
.B libpqvaptvupt
sealed-box integration. This option is unavailable unless ZUPT was built
with
.BR WITH_PQBOX=1 .
It is not enabled by the default source-only distribution build.
.
.SH EXTRACTION OPTIONS
.TP
.BR -o " " directory , " --output " directory
Extract below
.IR directory .
The directory is created when needed. The default is the current directory.
.
.PP
Extraction also accepts the password, PQ,
.BR -v ,
and
.B -t
options described above. Unlike compression, extract/list/test options may
appear before or after the single archive operand.
.
.SH TRUSTED LEGACY READ OPTION
.TP
.B --allow-legacy-no-ait
Permit recovery of a known, trusted historical archive that predates the
archive-integrity trailer. By default the validating read commands reject an
archive without an AIT, without trusting its unauthenticated header flags. This
option emits a downgrade warning and is accepted only by
.BR extract ,
.BR list ,
.BR test ,
and
.BR "disk restore" .
It is rejected by compression and disk backup, which always write a current
trailer.
.
.PP
Do not use this option for an archive obtained from untrusted or
attacker-writable storage. It does not authenticate the legacy header or footer.
After recovery, verify the restored data and create a new current archive.
.
.SH DISK OPTIONS
Disk options must precede the archive and device/file operands. Both disk
subcommands accept
.BR -l / --level ,
.BR -b / --block ,
.BR -s / --store ,
.BR --vv / --vaptvupt ,
.BR --lzhp ,
the password input options,
.BR --pq ,
.BR --pq-only ,
.BR -D / --dedup ,
.BR -c / --comment ,
.BR --comment-file ,
.BR --kdf ,
.BR -t / --threads ,
and
.BR -v / --verbose .
The optional SDK/PQBOX envelope options and solid mode are not disk-command
options.
.
.PP
.B --allow-legacy-no-ait
is accepted by disk restore only.
.
.SH KEY GENERATION OPTIONS
.TP
.BR -o " " file , " --output " file
Write the generated private key or exported public key to
.IR file .
This option is required.
.
.TP
.BR --pub
Export a public key from the private key selected by
.BR -k .
Use the same mode option as the private key.
.
.TP
.BR -k " " file , " --key " file
Read the source private key used by
.BR --pub .
.
.TP
.BR --pq-only , " --pqonly"
Generate or export a native ML-KEM-768-only key.
.
.TP
.BR --sdk , " --pq-sdk"
Generate an SDK-format key through the optional
.B libvuptsdk
integration.
.
.TP
.BR --box , " --pq-box"
Generate a sealed-box key through the optional
.B libpqvaptvupt
integration.
.
.PP
With no mode option,
.B keygen
generates or exports the native ML-KEM-768 plus X25519 hybrid format used by
.BR --pq .
.PP
Private-key output uses no-replace creation, POSIX mode 0600, or a Windows
current-user-only DACL. A write, flush, or close failure leaves the invalid
exclusive partial for manual removal rather than unlinking a possibly replaced
pathname. Native ZKEY and ZPQK inputs must have a valid checksum, version,
flags, reserved bytes, exact size, and public/private role; malformed or
role-confused keys are rejected.
.
.SH SECURITY NOTES
Use encrypted archives when an attacker may modify storage. Plain checksums are
not authentication. Keep private keys separate from archives, use high-entropy
passwords, and prefer
.BR --password-prompt ,
.BR --pass-file ,
or
.B --pass-fd
over argv passwords.
.PP
Archive comments remain untrusted display data even when authenticated. ZUPT
renders control bytes without emitting raw terminal-control sequences.
.
.PP
Extract untrusted archives as a dedicated unprivileged user into a new empty
local directory. POSIX builds canonicalize the user-selected output root once,
then traverse below a pinned directory descriptor with no-follow operations.
Windows builds use handle-relative traversal and
no-replace publication for normal local Win32 destinations. Extended-length and
device-namespace paths, raw UNC output roots, and mapped/network-drive output
are not supported in 5.2.7. Cross-compilation and Wine results are not native
Windows evidence; the native Windows package gate, including its Unicode round
trip, is separate and mandatory before publication.
.
.PP
Current encrypted archives protect ciphertext, canonical framing metadata,
logical frame position, and current header/footer metadata. The default AIT
requirement prevents a silent downgrade to a trailerless layout; the explicit
legacy override intentionally leaves old header/footer metadata outside that
authenticated boundary. ZUPT does not protect a compromised endpoint, a
disclosed credential, archive rollback or deletion, traffic analysis,
compression-length side channels, or every compiler and microarchitectural side
channel. Native PQ archive encryption is at-rest encryption, not session
forward secrecy.
.
.SH EXIT STATUS
.TP
.B 0
The requested operation completed successfully.
.
.TP
.B 1
Invalid arguments or an operational, format, authentication, integrity, or I/O
failure.
.
.SH FILES
.TP
.I /usr/bin/zupt
Distribution-installed command.
.
.TP
.I /usr/share/bash-completion/completions/zupt
Bash completion for the current command.
.
.TP
.I /usr/share/zsh/site-functions/_zupt
zsh completion for the current command.
.
.TP
.I /usr/share/fish/vendor_completions.d/zupt.fish
fish completion for the current command.
.
.SH EXAMPLES
Create a plain archive:
.PP
.RS
.B zupt compress backup.zupt Documents/
.RE
.
.PP
Create and restore a password-protected archive without placing the password in
argv:
.PP
.RS
.B zupt compress --password-prompt secure.zupt Documents/
.br
.B zupt test --password-prompt secure.zupt
.br
.B zupt extract --password-prompt -o restored secure.zupt
.RE
.
.PP
Use a password supplied on file descriptor 3:
.PP
.RS
.B zupt test --pass-fd 3 secure.zupt 3<password-file
.RE
.
.PP
Create a native hybrid recipient key and archive:
.PP
.RS
.B zupt keygen -o recipient.key
.br
.B zupt keygen --pub -k recipient.key -o recipient.pub
.br
.B zupt compress --pq recipient.pub backup.zupt Documents/
.br
.B zupt extract --pq recipient.key -o restored backup.zupt
.RE
.
.PP
Inspect and verify an archive without extraction:
.PP
.RS
.B zupt info backup.zupt
.br
.B zupt list backup.zupt
.br
.B zupt test backup.zupt
.RE
.
.SH COMPATIBILITY
The on-disk version byte remains v1.6, with flag-gated 5.2.2 encodings for
positional authenticated dedup references and disk-image integrity metadata.
Readers since 5.2.2 retain compatibility parsers for the fixed-width disk index
and the encrypted-dedup linear AAD sequence published through 5.2.1. The narrow
compatibility fixture is an actual v5.2.1 password-encrypted
DATA/DATA/REF/DATA disk archive stored as hexadecimal text with source and hash
provenance. The candidate lists, tests, extracts, and restores that fixture
byte-exact. The exact 5.2.7 candidate must repeat the gate. It does not imply
that a 5.2.1 reader
accepts every new 5.2.2 archive or that every historical encrypted mode was
retested.
.
.PP
The FIPS 203 correction in VaptVupt 5.0.0 changed
native
.B --pq
and
.B --pq-only
key/archive compatibility relative to releases through 4.2.1. Password and
plain archives were not affected by that KEM correction. Consult
.B CHANGELOG.md
before relying on cross-version recovery, and test restoration before depending
on a backup.
.
.SH LICENSE
The ZUPT application and tool code are AGPL-3.0-or-later. The bundled
VaptVupt codec source is GPL-3.0-or-later. The two xxHash-derived XXH64 units
also carry BSD-2-Clause. The pq-crystals/kyber-derived portions of native
ML-KEM also carry CC0-1.0; the x86 BCJ state machine is adapted from
public-domain LZMA SDK source. Native X25519 portions adapted from
curve25519-donna also carry BSD-3-Clause. Preserve
.BR LICENSE ,
.BR LICENSE-AGPL-3.0 ,
.BR LICENSE-GPL-3.0 ,
.BR LICENSE-BSD-2-Clause ,
.BR LICENSE-BSD-3-Clause ,
.BR LICENSE-CC0-1.0 ,
.BR NOTICE ,
and
.B THIRD-PARTY-NOTICES.md
when redistributing the source.
Published historical revisions include MIT grants for exact material shipped
with those notices; the current license summary does not revoke them. See the
5.2.2 licensing erratum in
.B CHANGELOG.md
for repository evidence.
.
.SH AUTHORS
Cristian Cezar Moisés is the primary upstream author and maintainer.
Packaging credits belong in their applicable packaging history and do not
imply authorship of the upstream program.
.
.SH REPORTING BUGS
Project issues:
.UR https://github.com/cristiancmoises/zupt/issues
ZUPT issue tracker
.UE
.
.PP
Report security vulnerabilities privately as described in
.BR SECURITY.md .
.
.SH SEE ALSO
.BR zupt-gui (1)