AccessBack, get my Excel password back! has got two questions from two distant parts of the world almost simultaneously:

“If I pay you for Excel decryption, will you send me my password to the document?”

The answer is already in the FAQ section of our website and is extremely laconic:

“No, we will not!”

That’s not about us being so mean to not telling you your Excel password. The reason is different: we don’t need the password to decrypt an Excel (or Word) document. We don’t retrieve it, and therefore we don’t know it.

This means you get your decrypted document, but not the password.

Here is how the thing works…

To decrypt data we need the encryption key, not the password itself. (This is true not only for Microsoft Office, but for any apps). The key is constructed based on the password using various algorithms and it can have varying length (the longer, the more secure).

Encryption of Excel (and Word) 97-2003 documents [by default] uses a very short encryption key – as short as 40 bits.

Such length of a key allows us to calculate rainbow tables containing [almost] entire array of keys. That’s literally what we did in Passcovery…

Now we simply take our original rainbow tables, scan them for a specific encryption key and use it to decrypt the Excel (or Word) file the service has obtained. All in all, it takes no more than a couple of minutes for to decrypt the file, and the result is guaranteed.

And the password remains unknown. It simply is not needed to decrypt Excel (and Word) docs!

Check it out, decrypt your Excel (or Word) document on — it’s free!

Decryption of a password-protected Excel file

A live example of how the things work is shown in the Passcovery Suite video. The full license includes a set of rainbow tables from Passcovery:

Useful links

Passcovery Suite — a universal solution to recover passwords on AMD/NVIDIA video cards.

Accent OFFICE Password Recovery — software to quickly restore passwords to all versions of Office/OpenOffice documents. Works on NVIDIA/AMD video cards.

AMD/NVIDIA video card performance — predicted NVIDIA/AMD video card performance when brute forcing passwords for MD5/SHA1 in Passcovery applications.