I have received a decrypted file from AccessBack. Please send me the password for the original document.

The AccessBack.com service does not recover passwords. It decrypts Excel/Word 97-03 documents without using a password (.doc/.xls files protected with a short 40-bit encryption key).

The service uses unique rainbow tables storing pre-calculated values of encryption keys for Excel/Word. The software finds a matching key in a table and decrypts the document.

As the result, you get an exact copy of the original document, but without password protection. The password, however, remains unknown.