(Visual Basic 6.0) Extract XML string from a .p7m byte array (e.g. FATTURA ELETTRONICA, ITALY)

Visual Basic 6.0 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 ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

Dim fac As New CkFileAccess
Dim p7mBytes() As Byte
p7mBytes = fac.ReadEntireFile("testData/p7m/fattura_signature.p7m")
If (fac.LastMethodSuccess <> 1) Then
    Debug.Print fac.LastErrorText
    Exit Sub
End If

Dim crypt As New ChilkatCrypt2

Dim originalXml As String
originalXml = crypt.OpaqueVerifyString(p7mBytes)
If (crypt.LastMethodSuccess <> 1) Then
    Debug.Print fac.LastErrorText
    Exit Sub
End If

Debug.Print "Original XML:"
Debug.Print originalXml

Debug.Print "Success!"