Sign with .pfx to create .p7s, Verify with .cer

Download: Chilkat .NET Assemblies

VB.NET example to sign a file using a .pfx and creating a .p7s file as output. It then uses a .cer file to verify the signature.

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


Dim certStore As New Chilkat.CertStore()
success = certStore.LoadPfxFile("chilkat.pfx","myPfxPassword")
If (success <> true) Then
    MsgBox(certStore.LastErrorText)
    Exit Sub
End If

Dim cert As Chilkat.Cert
cert = certStore.FindCertBySubjectCN("Chilkat Software, Inc.")
If (cert Is Nothing ) Then
    MsgBox("Failed to find certificate")
    Exit Sub
End If


'  We can explicitly choose hash/encryption algorithms using a CSP.
Dim csp As New Chilkat.Csp()
csp.SetProviderMicrosoftEnhanced()
csp.SetHashAlgorithm("sha-1")

'  Tell the crypt component to use this cert and this CSP.
crypt.SetSigningCert(cert)
crypt.SetCSP(csp)

'  We can sign any type of file, creating a .p7s as output:
success = crypt.CreateP7S("hamlet.xml","hamlet.p7s")
If (success = true) Then
    MsgBox("Signature created.")
Else
    MsgBox(crypt.LastErrorText)
End If


'  Verify and restore the original file:
'  Use a cert from a .cer file (which only contains the public key)
Dim cert2 As New Chilkat.Cert()
success = cert2.LoadFromFile("chilkat.cer")
If (success <> true) Then
    MsgBox(cert2.LastErrorText)
    Exit Sub
End If

crypt.SetVerifyCert(cert2)

success = crypt.VerifyP7S("hamlet.xml","hamlet.p7s")
If (success = true) Then
    MsgBox("Signature verified.")
Else
    MsgBox(crypt.LastErrorText)
End If