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How to generate an MD5 hash of a file from your program with wodCrypt ActiveX DLL

  For a copy of the sample project please click here to download and install the product evaluation.

Introduction

This solution demonstrates how wodCrypt will quickly and easily generate an MD5 hash for a specified file. wodCrypt is a lightweight component that provides strong encryption for your applications. Whenever you need to secure your transactions, wodCrypt's cryptography can be used. It provides support for most common crypto algorithms .

Detail

Our demonstration code illustrates a case in which we take a local file, and use it to calculate it's MD5 hash. The whole process is done in three simple steps.

Setup

Download and run the executable from the above link. The samples will be placed in directory C:\Program Files\WeOnlyDo.Com\Crypt\Samples. There are example projects for C#, VB, ASP, Delphi, VC and VBS.

In the VB6 project, add a reference to wodCryptCOM and event handlers are provided by the development environment.

In C#, wodCrypt is referenced as WODCRYPTCOMLib, and the all the necessary code is in the Form_Load Event.

VB6
      Dim wodCrypt As wodCryptCom
      Dim InFile As FileBlob
      Dim hash As FileBlob
   
      Set wodCrypt = New wodCryptCom
      Set InFile = New FileBlob
      Set hash = New FileBlob
  

C#
      WODCRYPTCOMLib.wodCryptCom wodCrypt = new WODCRYPTCOMLib.wodCryptCom();
      WODCRYPTCOMLib.FileBlobClass InFile = new WODCRYPTCOMLib.FileBlobClass();
      WODCRYPTCOMLib.FileBlobClass hash = new WODCRYPTCOMLib.FileBlobClass();

The first step is to declare and initialize the objects that we will use to achieve our goal. The code shown above does that.

The settings

In order to successfully calculate an MD5 hash we need to point our component to the file for which a hash is to be calculated, and set its digest to MD5:

VB6
      InFile.FileName = "c:\windows\notepad.exe"
      wodCrypt.Type = MD5

C#
      InFile.Filename = @"C:\Windows\notepad.exe";
      wodCrypt.Type = WODCRYPTCOMLib.CryptoTypes.MD5;

The Final step

Once we have selected the file to calculate, and set the digest we want to use, we can perform the actual calculation.

VB6
      wodCrypt.Digest InFile, hash
      MsgBox hash.ToHex

C#
      wodCrypt.Digest((WODCRYPTCOMLib.Blob)InFile,(WODCRYPTCOMLib.Blob)hash);
      MessageBox.Show(hash.ToHex());

The calculation is done in one method, Digest, and the calculated value is stored into a special WODCRYPTCOMLib.Blob object called "hash". The application will then show the result in a message box window using the ToHex() method of the hash object.

Summary

This simple demonstration shows an easy way to calculate hash values in three simple steps using wodCrypt to do the calculations for you.

For more sophisticated examples please follow the link below: