Use Certificate and Private Key PEM Files to Create a Digital Signature

Demonstrates how to load a digital certificate from a PEM file, load it's corresponding private key from a PEM file, save the private key to a key container (if necessary), link the certificate to the key container, and use it to create a digital signature.

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Dim cert As New Chilkat.Cert()

'  Load the cert from a PEM file;
cert.LoadFromFile("cert.pem")

Dim pkey As New Chilkat.PrivateKey()

'  Load the private key from an RSA PEM file:
pkey.LoadPemFile("pkey_rsa.pem")

Dim success As Boolean

'  If the "chilkat" key container does not already exist,
'  we'll create it and import the private key:
Dim container As New Chilkat.KeyContainer()
Dim needPrivateKeyAccess As Boolean
needPrivateKeyAccess = true
Dim machineKeyset As Boolean
machineKeyset = false
If (container.OpenContainer("chilkat",needPrivateKeyAccess,machineKeyset) = false) Then

    '  We need to create the key container and import
    '  the private key:
    success = container.CreateContainer("chilkat",machineKeyset)
    If (success = true) Then
        Dim isKeyExchangePair As Boolean
        isKeyExchangePair = false
        success = container.ImportPrivateKey(pkey,isKeyExchangePair)
        If (success = false) Then
            TextBox1.Text = TextBox1.Text & "Failed to import private key into key container" & vbCrLf
            Exit Sub
        End If

    Else
        TextBox1.Text = TextBox1.Text & "Failed to create key container" & vbCrLf
        Exit Sub
    End If

End If


'  At this point, the key container contains the private key.
'  Link the certificate with the key container:
Dim bForSigning As Boolean
bForSigning = true
success = cert.LinkPrivateKey("chilkat",machineKeyset,bForSigning)
If (success = false) Then
    TextBox1.Text = TextBox1.Text & "Failed to link certificate with key container" & vbCrLf
    Exit Sub
End If


'  Use Chilkat Crypt (a non-freeware component) to create
'  a digital signature using the certificate w/ private key:
Dim crypt As New Chilkat.Crypt2()

'  Any string argument automatically begins the 30-day trial.

success = crypt.UnlockComponent("30-day trial")
If (success <> true) Then
    MsgBox("Crypt component unlock failed")
    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

TextBox1.Text = TextBox1.Text & crypt.LastErrorText & vbCrLf

'  Verify and restore the original file:
crypt.SetVerifyCert(cert)

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

    Exit Sub
End If


MsgBox("Success!")


'  The Chilkat Certificate, Certificate Store, Private Key,
'  Public Key, and Key Container classes / objects are freeware.

'  They are used by and included with the Chilkat Email,
'  Crypt, S/MIME, and other commercial Chilkat components.