DataFlex

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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DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoMime
    Integer n
    Variant vCert
    Handle hoCert
    Integer i
    String sTemp1
    String sTemp2

    Move False To iSuccess

    Get Create (RefClass(cComChilkatMime)) To hoMime
    If (Not(IsComObjectCreated(hoMime))) Begin
        Send CreateComObject of hoMime
    End
    Get ComLoadMimeFile Of hoMime "qa_data/signed.eml" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoMime To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  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.
    Get ComVerify Of hoMime To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoMime To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComNumSignerCerts Of hoMime To n
    Get Create (RefClass(cComChilkatCert)) To hoCert
    If (Not(IsComObjectCreated(hoCert))) Begin
        Send CreateComObject of hoCert
    End

    For i From 0 To (n - 1)
        Get pvComObject of hoCert to vCert
        Get ComLastSignerCert Of hoMime i vCert To iSuccess
        If (iSuccess = False) Begin
            Get ComLastErrorText Of hoMime To sTemp1
            Showln sTemp1
            Procedure_Return
        End

        Get ComSubjectCN Of hoCert To sTemp1
        Get ComIssuerCN Of hoCert To sTemp2
        Showln "Signer " i ": " sTemp1 " (issued by " sTemp2 ")"
    Loop



End_Procedure