The hash of file is its digital fingerprint that uniquely identifies that file. If the contents of a file change, its hash would also change. This is why file hashes are used for determining if a file has undergone any changes. Some software distributors display file hashes on their websites for everyone, helping them to check if the downloaded file is altered (for example, by hackers or malware) or not. HashTab is a simple Windows Explorer extension which makes it very easy to calculcate and check file hashes in Windows.
Unlike other programs, HashTab is tighly integrated with Windows Explorer. It adds an extra tab in the File Properties dialog displaying the file hashes. After installing HashTab in your Windows system, just right-click on any file and select Properties from the right-click context menu. In the File Properties dialog, you would see a new tab labeled File Hashes. You can copy-paste a file hash in the Hash Comparison text box to compare it with the calculated hashes. If the hashes match, you would see a green checkmark. If the hashes d not match, then you would see a red crossmark. By default, it shows only the CRC32, MD5 and SHA-1 hashes of the selected file.
But HashTab supports many other hash algorithms including Adler32, BTIH, CRC32, ED2K, GOST, MD2, MD4, MD5, RIPEMD-128, RIPEMD-256, RIPEMD-320, SHA-1, SHA-256, SHA-384, SHA-512, TTH, Tiger and Whirlpool. To display more of the file hash types, click on the Settings link in the File Properties dialog’s File Hashes tab. This would open a settings window where you can select various file hashing algorithm to be displayed for a file.
In addition to the simple hash calculation, HashTab also allows you to compare two files and check whether they are identical. To compare two files, right-click on one of those files and select Properties from the right-click context menu. In the File Hashes tab, click on the Compare a file button and select the second file. If the two files are identical, then their hashes would match and you would see the green check mark.
HashTab is a very simple way to calculate and check file hashes. It supports a large number of hashing algorithms. It also includes a quick file comparision function. It makes all the file hashing business considerably simpler and easier.
You can download HashTab from http://www.implbits.com/HashTab/.