Sign a Byte Array to Create a Hex-Encoded Signature

Download: Chilkat .NET Assemblies

This example program signs an in-memory byte array and creates a hex encoded digital signature string. It also verifies the original byte data against the signature.

        ' This example uses the Chilkat .NET encryption library, which can be downloaded
        ' at http://www.chilkatsoft.com/downloads.asp

        ' Create an instance of the Chilkat encryption class.
        Dim success As Boolean
        Dim crypt As New Chilkat.Crypt2()

        ' Any code begins the 30-day trial.
        crypt.UnlockComponent("30-day-trial")

        ' Load a certificate from a .cer file
        ' There are many other ways of loading a certificate...
        Dim cert As New Chilkat.Cert()
        success = cert.LoadFromFile("myCert.cer")
        If (Not success) Then
            MsgBox(cert.LastErrorText)
            Exit Sub
        End If

        ' Tell the crypt object to use the certificate.
        crypt.SetSigningCert(cert)

        ' Tell the crypt object to hexidecimalize the resultant signature.
        crypt.EncodingMode = "hex"

        ' File a byte array to sign
        Dim inputData(10) As Byte
        Dim i As Integer
        For i = 1 To 10
            inputData(i) = i
        Next

        ' Sign the byte array.
        Dim hexSignature As String
        hexSignature = crypt.SignBytesENC(inputData)
        If (hexSignature.Length = 0) Then
            MsgBox(crypt.LastErrorText)
            Exit Sub
        End If

        MsgBox("Digital signature created!")

        ' Now verify the signature.
        Dim verified As Boolean
        verified = crypt.VerifyBytesENC(inputData, hexSignature)
        If Not verified Then
            MsgBox(crypt.LastErrorText)
        Else
            MsgBox("Signature verified!")
        End If

Important: The download for this example does not contain the ChilkatDotNet.dll which
must be downloaded and installed separately at http://www.chilkatsoft.com/downloads.asp.
Once installed, add a reference to the DLL in the project by following the instructions at
http://www.example-code.com/vbdotnet/step2.asp