(VB.NET) Extract XML string from a .p7m byte array (e.g. FATTURA ELETTRONICA, ITALY)

VB.NET example to extract the original XML from a .p7m (Signed-Data PKCS7 Format) provided as a byte array.

One use for this example is to extract the original XML from a Fattura Elettronica .p7m signature.

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 fac As New Chilkat.FileAccess
Dim p7mBytes() As Byte
p7mBytes = fac.ReadEntireFile("testData/p7m/fattura_signature.p7m")
If (fac.LastMethodSuccess <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If


Dim crypt As New Chilkat.Crypt2

Dim originalXml As String = crypt.OpaqueVerifyString(p7mBytes)
If (crypt.LastMethodSuccess <> True) Then
    Debug.WriteLine(fac.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Original XML:")
Debug.WriteLine(originalXml)

Debug.WriteLine("Success!")