Unicode C

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.

Chilkat Unicode C Downloads

Download Chilkat for Unicode C

Unicode C

#include <C_CkDkimW.h>
#include <C_CkPrivateKeyW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkDkimW dkim;
    HCkPrivateKeyW 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 = CkDkimW_Create();

    //  Load the RSA private key that corresponds to the public key published in the domain's DNS.
    privKey = CkPrivateKeyW_Create();
    success = CkPrivateKeyW_LoadPemFile(privKey,L"qa_data/dkim_private.pem");
    if (success == FALSE) {
        wprintf(L"%s\n",CkPrivateKeyW_lastErrorText(privKey));
        CkDkimW_Dispose(dkim);
        CkPrivateKeyW_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 = CkDkimW_SetDkimPrivateKey(dkim,privKey);
    if (success == FALSE) {
        wprintf(L"%s\n",CkDkimW_lastErrorText(dkim));
        CkDkimW_Dispose(dkim);
        CkPrivateKeyW_Dispose(privKey);
        return;
    }

    wprintf(L"DKIM private key configured.\n");


    CkDkimW_Dispose(dkim);
    CkPrivateKeyW_Dispose(privKey);

    }