The most common applications that are used in day to day word and data processing such as Microsoft Word, Excel, PowerPoint, etc. all come with password protection capabilities.
Also, there are compression software such as WinZip, Winrar, 7Z, etc. which allow for compression of files.
These applications also have the capability of password protecting the compressed file. The password protection feature allows the authors and creators of the files to protect the document and make them only accessible to users to whom they have voluntarily given the password.
But, there are cases when the creator or the author of the file forgot the password thus making the file inaccessible.
For this reason there are password recovery applications that are freely as well as commercially available in the market. They would allow users who have forgotten the password to their files to retrieve the password and access the files again.
The password recovery tools are available in either bundle package or separate for each application for which the password has to be recovered. The technologies that are employed for the password recovery range from brute force technology commonly known as the brute force attack to the dictionary based approach.
There are also cases when hybrid methodology is employed which makes partial use of both the above methods.
There are other tools as well that would simply remove the password from the file itself. These are called the password removal tools. In case the password recovery tools are not successful in recovering the password to the file, password removal tools can be used.
Password removal tools are available for mostly all documents like Word, Excel, Access, pdf, zip, etc.