What is synthetic, and what stays visible?
The clean workbook uses neutral worksheet names and retains original headers in row 1, dates, layout, basic number and date formats, and empty cells. Other text, names, emails and IDs are replaced consistently; generic text becomes synthetic labels. Name detection uses a header-based heuristic. Numbers use independent synthetic ranges.
Original headers, dates, repetition and relationships intentionally stay visible. The synthetic workbook is not a guarantee of anonymity.
The same passkey or its recovery phrase restores the encrypted original. Modified protected content is rejected. Older password-protected ExcelKey files can still be restored with their password.
Keep the downloaded workbook intact. Editing or resaving it in Excel can prevent restoration. Restore the original before making changes.
Original charts, pivots, macros, metadata, images, hyperlinks, comments and formulas are not carried into the visible output. Date formulas are frozen to their cached date values. These original features remain only in the encrypted original.
Generation always downloads synthetic.protected.xlsx, regardless of the original filename or format. Accepted inputs are .xlsx, .xlsm, .xltx, .xltm, .xls, .xlsb, .xlt and XML workbooks; restoration returns the original format and content.
Files and encryption secrets stay in this browser. No accounts or uploads.