Unprotect an Excel sheet, or add or remove a password on your office file OFFICEKEY
Sheet protection and restrict editing are flags, not encryption, and come off without a password. A password to open is real encryption: give it the password and it opens the file, or it puts one on. It never guesses.
Your file
An older format
It has a password to open
You need the password. This page does not guess, try lists of passwords, or get round the encryption, and nothing else honestly can: without the password the contents are unreadable, which is the point of it.
Open.
Editing restrictions
Sheet protection, workbook protection, “restrict editing” and “read-only recommended” are not encryption. The file is readable by anything that opens it; Office just chooses to honour a flag. Taking the flag out needs no password.
Put a password on it
Encrypted as Office 2010 and later encrypt: AES-256, with the key derived from the password by 100,000 rounds of SHA-512. Word, Excel and PowerPoint, and LibreOffice, ask for the password to open it. Nobody can get it back for you if it is lost.
How it works
OFFICEKEY works on Word, Excel and PowerPoint files you own. It takes sheet protection, workbook protection, restrict editing and read-only recommended out of a copy, opens a file encrypted with a password when you know the password, and encrypts a file with a password to open the way Office 2010 and later do. It does not guess or crack passwords. Nothing leaves this tab.
What this does, and what it will not do
Office has two kinds of password and they are not alike. A password to open encrypts the file: without it the contents are unreadable. OFFICEKEY opens one when you give it the password, and puts one on a file for you; it does not guess or crack passwords, and there is no way round one that is honest.
A restriction (protect sheet, protect workbook, restrict editing, read-only recommended, a password to modify) is a flag in an unencrypted file. It stops mistakes, not people, and OFFICEKEY takes it out of a copy without any password. Use it on your own files, or files you have the right to change: a template whose protection password was lost, a workbook left by a colleague who has gone. Unprotecting an Excel sheet shows where the flag is kept and how to take it out by hand.
It handles the formats Office has used since 2007 (.docx, .xlsx, .pptx and their macro versions). The older .doc, .xls and .ppt use RC4 and other schemes this page does not handle. Everything happens in this tab; the file and the password are not sent anywhere.
Doing this often? The OBSCURA Sovereign Suite seals files so that only the person with the passphrase opens them, and can lock one so it takes several people to open. On its own, US$2 a month; with everything else, US$5 a month or US$48 a year. 7 days free.