Many times we face situations where a bug is not reproducible on a particular version in our environment, but the customer or supports says, that its reproducible at their ends, but they can't share that environment due to security concerns.

Most of the times it can be some configuration issue or some patch applied in the customer environment. We can easily verify that the files in the customer environment is the same as the one that we uses to reproduce the issue, instead of asking customer to zip their environment and send to us, using the file hashes/checksums.

The File Checksum Integrity Verifier (FCIV) is a command-prompt utility that computes and verifies cryptographic hash values of files. FCIV can compute MD5 or SHA-1 cryptographic hash values. These values can be displayed on the screen or saved in an XML file database for later use and verification.

FCIV command is easy to use and can recursively compute the checksums of all the files in a folder and you can also specify file type filter.

fciv.exe c:\mydir -r -wp -sha1 -type *.dll -xml db.xml

More information and download links is available in the Microsoft support article at: http://support.microsoft.com/kb/841290

If you are looking for some graphical tool, then HashMyFiles is a good freeware tool for this purpose. HashMyFiles is small utility that allows you to calculate the MD5 and SHA1 hashes of one or more files in your system. You can easily copy the MD5/SHA1 hashes list into the clipboard, or save them into text/html/xml file. HashMyFiles can also be launched from the context menu of Windows Explorer, and display the MD5/SHA1 hashes of the selected file or folder.