Need Help File Signature/ Header from DB

Hello All, I am a newbie in VB.NET, and I am learning, I need to do my project using VB.NET & SQL 2005 the project is about reading the File signature/ Header /Magic number from the OpenFileDialog/BrowseFile Dialog from where the user randomly selects any file, and then that selected file's Header ,signature values in HEX needs to be compared with SQL db containg the precomputed signatures of known files. how can i go about this comparing something selected @ random by user with backend. and display the file signature and file extension from the db, also the fileext and signature needs to be displayed as result to the user. for example: FF D8 =.JPG file here FFD8 is the file signature HEADER for a JPG file type with extension of .JPG can someone help me with this. Thanks in advance