(Visual Basic) Extract a File from a .p7m (PKCS7 Signed-Data)

Visual Basic example to extract the original file from a .p7m (Signed-Data PKCS7 Format) The .p7m contains the signed contents of the original file. It can be verified and restored by calling VerifyP7M.

Download Chilkat Crypt ActiveX

Dim crypt As New ChilkatCrypt2

'  Any string argument automatically begins the 30-day trial.
Dim success As Long
success = crypt.UnlockComponent("30-day trial")
If (success <> 1) Then
    Text1.Text = Text1.Text & crypt.LastErrorText & vbCrLf
    Exit Sub
End If

Dim outFile As String
outFile = "/Users/chilkat/testData/pdf/sample.pdf"
Dim inFile As String
inFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m"

'  Verify and restore the original file:
success = crypt.VerifyP7M(inFile,outFile)
If (success = 0) Then
    Text1.Text = Text1.Text & crypt.LastErrorText & vbCrLf
    Exit Sub
End If

MsgBox "Success!"