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

Download: Chilkat .NET Assemblies

VB.NET 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.

Dim crypt As New Chilkat.Crypt2()

'  Any string argument automatically begins the 30-day trial.
Dim success As Boolean
success = crypt.UnlockComponent("30-day trial")
If (success <> true) Then
    MsgBox("Crypt component unlock failed")
    Exit Sub
End If


'  Find our digital certificate from the Current User certificate store.
Dim ccs As New Chilkat.CreateCS()
Dim certStore As Chilkat.CertStore
certStore = ccs.OpenCurrentUserStore()
Dim cert As Chilkat.Cert
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 = false) Then
    MsgBox(crypt.LastErrorText)

    Exit Sub
End If


'  Verify the signature:
crypt.SetVerifyCert(cert)

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

    Exit Sub
End If




MsgBox("Success!")