Tcl

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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Tcl


load ./chilkat.dll

set success 0

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

set dkim [new_CkDkim]

#  Load the RSA private key that corresponds to the public key published in the domain's DNS.
set privKey [new_CkPrivateKey]

set success [CkPrivateKey_LoadPemFile $privKey "qa_data/dkim_private.pem"]
if {$success == 0} then {
    puts [CkPrivateKey_lastErrorText $privKey]
    delete_CkDkim $dkim
    delete_CkPrivateKey $privKey
    exit
}

#  Copy the key into the Dkim object.  The PrivateKey object may be destroyed afterward, and the
#  configured key can be reused for multiple signatures.
set success [CkDkim_SetDkimPrivateKey $dkim $privKey]
if {$success == 0} then {
    puts [CkDkim_lastErrorText $dkim]
    delete_CkDkim $dkim
    delete_CkPrivateKey $privKey
    exit
}

puts "DKIM private key configured."

delete_CkDkim $dkim
delete_CkPrivateKey $privKey