Set the DKIM Signing Private Key

See more DKIM / DomainKey Examples

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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#include <C_CkDkim.h>
#include <C_CkPrivateKey.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkDkim dkim;
    HCkPrivateKey privKey;

    success = FALSE;

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

    dkim = CkDkim_Create();

    //  Load the RSA private key that corresponds to the public key published in the domain's DNS.
    privKey = CkPrivateKey_Create();
    success = CkPrivateKey_LoadPemFile(privKey,"qa_data/dkim_private.pem");
    if (success == FALSE) {
        printf("%s\n",CkPrivateKey_lastErrorText(privKey));
        CkDkim_Dispose(dkim);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    //  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_SetDkimPrivateKey(dkim,privKey);
    if (success == FALSE) {
        printf("%s\n",CkDkim_lastErrorText(dkim));
        CkDkim_Dispose(dkim);
        CkPrivateKey_Dispose(privKey);
        return;
    }

    printf("DKIM private key configured.\n");


    CkDkim_Dispose(dkim);
    CkPrivateKey_Dispose(privKey);

    }