Visual Basic 6.0

Create an Opaque Signature with a Separate Private Key

Demonstrates the Chilkat Mime.ConvertToSignedPk method, which creates an opaque signature using a signer certificate and its separately supplied private key. The first argument is the Cert and the second is the PrivateKey.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: The separate-key form of ConvertToSigned, for when the certificate and private key are not bundled together. It produces the same opaque CMS signed-data result; only the source of the key material differs.

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Visual Basic 6.0

Dim success As Long
success = 0

Dim mime As New ChilkatMime
success = mime.SetBodyFromPlainText("This message will be signed.")
If (success = 0) Then
    Debug.Print mime.LastErrorText
    Exit Sub
End If

'  Load the certificate and its private key separately.
Dim cert As New ChilkatCert
success = cert.LoadFromFile("qa_data/signer.cer")
If (success = 0) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

Dim privKey As New PrivateKey
success = privKey.LoadPemFile("qa_data/signer_privkey.pem")
If (success = 0) Then
    Debug.Print privKey.LastErrorText
    Exit Sub
End If

'  Create an opaque signature when the certificate and private key are supplied separately.  The
'  1st argument is the signer certificate and the 2nd is its private key.
success = mime.ConvertToSignedPk(cert,privKey)
If (success = 0) Then
    Debug.Print mime.LastErrorText
    Exit Sub
End If

success = mime.SaveMime("qa_output/signed_opaque.eml")
If (success = 0) Then
    Debug.Print mime.LastErrorText
    Exit Sub
End If

Debug.Print "Message converted to an opaque signed message."