PureBasic

Set the DKIM Signing Private Key

Demonstrates the Chilkat Dkim.SetDkimPrivateKey method, which supplies the RSA private key used by DkimSign. The only argument is a PrivateKey object. The source key may be destroyed after this returns, and the configured key can be reused for multiple signatures.

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: DKIM proves a message really came from its domain by signing it with a private key that only the domain owner holds; recipients verify with the matching public key published in the domain's DNS. This method loads that private half into the Dkim object once, so a mail server can sign every outgoing message without re-reading the key each time. Because the key is the domain's signing secret, it should be protected like any other private key and never committed to source.

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IncludeFile "CkPrivateKey.pb"
IncludeFile "CkDkim.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  Demonstrates the Dkim.SetDkimPrivateKey method, which supplies the RSA private key used by
    ;  DkimSign.  The only argument is a PrivateKey object.

    dkim.i = CkDkim::ckCreate()
    If dkim.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Load the RSA private key that corresponds to the public key published in the domain's DNS.
    privKey.i = CkPrivateKey::ckCreate()
    If privKey.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPrivateKey::ckLoadPemFile(privKey,"qa_data/dkim_private.pem")
    If success = 0
        Debug CkPrivateKey::ckLastErrorText(privKey)
        CkDkim::ckDispose(dkim)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    ;  Copy the key into the Dkim object.  The PrivateKey object may be destroyed afterward, and the
    ;  configured key can be reused for multiple signatures.
    success = CkDkim::ckSetDkimPrivateKey(dkim,privKey)
    If success = 0
        Debug CkDkim::ckLastErrorText(dkim)
        CkDkim::ckDispose(dkim)
        CkPrivateKey::ckDispose(privKey)
        ProcedureReturn
    EndIf

    Debug "DKIM private key configured."


    CkDkim::ckDispose(dkim)
    CkPrivateKey::ckDispose(privKey)


    ProcedureReturn
EndProcedure