Sign a File to Create a .p7s File (Detached Signature)

Visual Basic example to create a detached signature file (.p7s) for any type file. The signature can be verified by calling VerifyP7S and passing the original filename and the .p7s filename.

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
    MsgBox "Crypt component unlock failed"
    Exit Sub
End If

'  Find our digital certificate from the Current User certificate store.
Dim ccs As New ChilkatCreateCS
Dim certStore As ChilkatCertStore
Set certStore = ccs.OpenCurrentUserStore()
Dim cert As ChilkatCert
Set cert = certStore.FindCertBySubjectCN("Chilkat Software, Inc.")
If (cert Is Nothing ) Then
    MsgBox cert.LastErrorText

    Exit Sub
End If

'  Tell the crypt component to use this cert.
crypt.SetSigningCert cert

'  We can sign any type of file, creating a .p7s as output:
success = crypt.CreateP7S("license.rtf","license.p7s")
If (success = 0) Then
    MsgBox crypt.LastErrorText

    Exit Sub
End If

'  Verify the signature:
crypt.SetVerifyCert cert

success = crypt.VerifyP7S("license.rtf","license.p7s")
If (success = 0) Then
    MsgBox crypt.LastErrorText

    Exit Sub
End If

MsgBox "Success!"