PowerBuilder

Get the S/MIME Signer's Certificate

Demonstrates the Chilkat Mime.LastSignerCert method, which loads the signer certificate at a zero-based index from the most recent successful verification (or security-unwrapping) into a Cert. The first argument is the signer index and the second is the receiving 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: Verifying tells you the signature is mathematically valid, but you usually also need to know who signed — the subject, the issuer, the validity dates — to decide whether to trust it. This retrieves each signer's certificate after verification so your code can inspect and apply its own trust rules. A message can have multiple signers, so iterate from 0 to NumSignerCerts - 1.

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PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Mime
integer n
oleobject loo_Cert
integer i

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

//  After a successful verification, load each signer's certificate to inspect it.  The 1st argument
//  is the zero-based signer index and the 2nd is a Cert object that receives the certificate.
li_Success = loo_Mime.Verify()
if li_Success <> 1 then
    Write-Debug loo_Mime.LastErrorText
    destroy loo_Mime
    return
end if

n = loo_Mime.NumSignerCerts
loo_Cert = create oleobject
li_rc = loo_Cert.ConnectToNewObject("Chilkat.Cert")

for i = 0 to n - 1
    li_Success = loo_Mime.LastSignerCert(i,loo_Cert)
    if li_Success = 0 then
        Write-Debug loo_Mime.LastErrorText
        destroy loo_Mime
        destroy loo_Cert
        return
    end if

    Write-Debug "Signer " + string(i) + ": " + loo_Cert.SubjectCN + " (issued by " + loo_Cert.IssuerCN + ")"
next


destroy loo_Mime
destroy loo_Cert