Objective-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.

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Objective-C

#import <CkoDkim.h>
#import <CkoPrivateKey.h>

BOOL success = NO;

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

CkoDkim *dkim = [[CkoDkim alloc] init];

//  Load the RSA private key that corresponds to the public key published in the domain's DNS.
CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];
success = [privKey LoadPemFile: @"qa_data/dkim_private.pem"];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    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 = [dkim SetDkimPrivateKey: privKey];
if (success == NO) {
    NSLog(@"%@",dkim.LastErrorText);
    return;
}

NSLog(@"%@",@"DKIM private key configured.");