Objective-C

Send DKIM Signed Email

See more DKIM / DomainKey Examples

Demonstrates how to send DKIM signed email. Objective-C

#import <CkoMailMan.h>
#import <CkoDkim.h>
#import <CkoEmail.h>
#import <CkoBinData.h>
#import <NSString.h>
#import <CkoPrivateKey.h>

BOOL success = NO;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

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

//  SMTP server settings...
mailman.SmtpHost = @"SMTP_DOMAIN";
mailman.SmtpUsername = @"SMTP_LOGIN";
mailman.SmtpPassword = @"SMTP_PASSWORD";
mailman.SmtpPort = [NSNumber numberWithInt:465];
mailman.SmtpSsl = YES;

CkoEmail *email = [[CkoEmail alloc] init];

email.Subject = @"This is a test";
email.Body = @"This is a test";
email.From = @"Chilkat Support <support@chilkatsoft.com>";

//  Add some recipients (BCC recipients are added below)
[email AddTo: @"Chilkat Software" emailAddress: @"chilkat_software@yahoo.com"];
[email AddTo: @"Chilkat Admin" emailAddress: @"admin@chilkatsoft.com"];
[email AddCC: @"Chilkat Admin" emailAddress: @"admin@chilkat.io"];

//  When sending an email with a DKIM signature, the MIME
//  of the email must not be modified prior to
//  or during the sending process.  Therefore, the MIME of the
//  email is assembled, the DKIM signature is added, and then
//  SendMimeBd is called to send the email.

//  First get the MIME of the email.  Calling RenderToMimeBd 
//  causes the email to be signed and/or encrypted if those options
//  have been selected.  The MIME returned by RenderToMimeBd
//  is the exact MIME that would've been sent if SendEmail was
//  called.  We'll add a DKIM signature header to this MIME and then send...
CkoBinData *bdMime = [[CkoBinData alloc] init];
success = [mailman RenderToMimeBd: email renderedMime: bdMime];
if (success == NO) {
    NSLog(@"%@",mailman.LastErrorText);
    return;
}

//  To create a DKIM signature,
//  you'll need to provide the following:
//  (1) An RSA private key in any common file format.
//  (2) The domain name (typically the same domain
//  as the sender of an email).
//  (3) A selector for the domain name -- an arbitrary string
//  to identify the matching public key in DNS.

//  To allow an email recipient to verify the DKIM signature via an
//  external email client supporting DKIM or using other software,
//  you will need to create a DNS record with the selector
//  and matching public key.  This example does not provide
//  information about DKIM DNS record creation.  
//  (Chilkat does not provide an API for creating DNS records.  
//  Creating the DKIM DNS record is something you would do
//  manually.)

//  Set the domain and selector:
//  You'll need to provide your own values here..
dkim.DkimDomain = @"chilkatsoft.com";
dkim.DkimSelector = @"brisbane";

//  Load a private key from any common RSA private key
//  format, such as DER, PKCS8, PEM, XML, etc.
//  The LoadDkimPkFile method automatically detects
//  the file format and reads it appropriately.
//  If a password is not required, you'll still need to provide
//  an empty password string argument, but it is ignored.
NSString *password = @"passwd";
CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];
success = [privKey LoadAnyFormatFile: @"qa_data/pem/rsa_passwd.pem" password: password];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

success = [dkim SetDkimPrivateKey: privKey];
if (success == NO) {
    NSLog(@"%@",dkim.LastErrorText);
    return;
}

//  Add the DKIM-Signature header to the MIME in bdMime
success = [dkim DkimSign: bdMime];
if (success == NO) {
    NSLog(@"%@",dkim.LastErrorText);
    return;
}

//  If desired, examine the MIME of the email being sent.
[bdMime WriteFile: @"qa_output/dkimSigned.eml"];

//  ---- Prepare to send the email contained in bdMime ---

//  To send to multiple email addresses, the strRecipients should be set to a comma-separated
//  list of email addresses.

//  Note: This is where we can add additional BCC addreses.
//  Here we are adding "chilkat.support@gmail.com" as an additional BCC address.
//  Notice that the 1st three email addresses are NOT BCC because these email addresses
//  appear in the MIME header of the email (in the "To" and "CC" header fields).
//  A BCC email address does not appear in the MIME, and thus the non-BCC recipients cannot see
//  that the email was also sent to the BCC address.  (BCC means "blind carbon copy")
NSString *strRecipients = @"chilkat_software@yahoo.com, admin@chilkatsoft.com, admin@chilkat.io, chilkat.support@gmail.com";
NSString *strFrom = @"support@chilkatsoft.com";

success = [mailman SendMimeBd: strFrom recipients: strRecipients mimeData: bdMime];
if (success == NO) {
    NSLog(@"%@",mailman.LastErrorText);
    return;
}

success = [mailman CloseSmtpConnection];
if (success != YES) {
    NSLog(@"%@",@"Connection to SMTP server not closed cleanly.");
}

NSLog(@"%@",@"DKIM Signed Mail Sent!");