PowerBuilder

Supply a Fallback Certificate for S/MIME Verification

Demonstrates the Chilkat Mime.SetVerifyCert method, which supplies a signer-certificate fallback for subsequent signature verification. The only argument is the Cert.

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: Most signed messages embed the signer's certificate, so Verify can find it automatically. But some signatures omit it to save space, expecting the recipient to already have it. This method provides that certificate as a fallback so verification can proceed — the S/MIME equivalent of already knowing the sender's public key out of band.

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PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Mime
oleobject loo_Cert

li_Success = 0

loo_Mime = create oleobject
li_rc = loo_Mime.ConnectToNewObject("Chilkat.Mime")
if li_rc < 0 then
    destroy loo_Mime
    MessageBox("Error","Connecting to COM object failed")
    return
end if
li_Success = loo_Mime.LoadMimeFile("qa_data/signed.eml")
if li_Success = 0 then
    Write-Debug loo_Mime.LastErrorText
    destroy loo_Mime
    return
end if

//  Supply a signer-certificate fallback for verification.  This is useful when the signature does
//  not embed the signer certificate and Chilkat cannot otherwise locate it.
loo_Cert = create oleobject
li_rc = loo_Cert.ConnectToNewObject("Chilkat.Cert")

li_Success = loo_Cert.LoadFromFile("qa_data/signer.cer")
if li_Success = 0 then
    Write-Debug loo_Cert.LastErrorText
    destroy loo_Mime
    destroy loo_Cert
    return
end if

li_Success = loo_Mime.SetVerifyCert(loo_Cert)
if li_Success = 0 then
    Write-Debug loo_Mime.LastErrorText
    destroy loo_Mime
    destroy loo_Cert
    return
end if

//  Now verify using the supplied certificate.
li_Success = loo_Mime.Verify()
if li_Success <> 1 then
    Write-Debug loo_Mime.LastErrorText
    destroy loo_Mime
    destroy loo_Cert
    return
end if

Write-Debug "Signature verified using the supplied certificate."


destroy loo_Mime
destroy loo_Cert