Careful at every boundary.

Sheet Zipper uses bounded package parsing, path validation, checksums, temporary-file isolation, and no-overwrite publication to reduce the risk of malformed or changing inputs.

Output integrity

• Optimization candidates are checked before publication.
• XLZ archives carry package and entry checksums.
• Restored workbooks are analyzed again before they appear at the selected destination.
• Source identity is rechecked during long-running work to detect replacement or modification.

Report a vulnerability

Send private reports to support@evernivo.com with the subject “Private security report”. Include the application version, operating system, error code, and a minimal synthetic reproduction.

Do not attach sensitive or proprietary workbooks to public GitHub issues.