Hashtab

HashTab provides OS extensions to calculate file hashes. HashTab supports many hash algorithms such as MD5, SHA1, SHA2, RipeMD, HAVAL and Whirlpool. HashTab is supported as a Windows shell extension and a Mac Finder plugin. HashTab provides an easy way to verify file integrity and authenticity. Tens of thousands have downloaded HashTab!

Download: http://implbits.com/HashTab.aspx