(VB.NET) Sign a Byte Array to Create an Opaque Signature in a Byte Array

Signs data contained in a byte array to produce an opaque signature (also in a byte array). An opaque signature is a PKCS7 signature (also known as CAdES) that embeds the signed data. Also shows how to verify the signature and extract the original data.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim cert As New Chilkat.Cert
Dim success As Boolean = cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Dim fac As New Chilkat.FileAccess

Dim fileBytes() As Byte
fileBytes = fac.ReadEntireFile("qa_data/pdf/sample.pdf")
If (fac.LastMethodSuccess <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If


Dim crypt As New Chilkat.Crypt2

success = crypt.SetSigningCert(cert)

' We can sign any type of file.

Dim sigBytes() As Byte
sigBytes = crypt.OpaqueSignBytes(fileBytes)
If (crypt.LastMethodSuccess <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If


success = fac.WriteEntireFile("qa_output/sample.pdf.p7m",sigBytes)
If (fac.LastMethodSuccess <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If



' We can verify the opaque signature and extract the original data like this
Dim originalData() As Byte
originalData = crypt.OpaqueVerifyBytes(sigBytes)
If (crypt.LastMethodSuccess <> True) Then
    Debug.WriteLine(crypt.LastErrorText)
    Exit Sub
End If



success = fac.WriteEntireFile("qa_output/sample.pdf",originalData)
If (fac.LastMethodSuccess <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Signature is verified and the original data was extracted.")