Verify Message

Verifies the DKIM signature of a MIME message.

Code

using DRIT.Mail.Rfc.Dkim;
using DRIT.Mail.Rfc.Mime;

MimeMessage message = MimeMessage.Load("signed.eml");

var resolver = new DkimDnsKeyResolver();
var verifier = new DkimVerifier(resolver);

DkimVerificationResult result = verifier.Verify(message);

Console.WriteLine($"Status:        {result.Status}");
Console.WriteLine($"Domain:        {result.Domain}");
Console.WriteLine($"Selector:      {result.Selector}");
Console.WriteLine($"Algorithm:     {result.SigningAlgorithm}");

if (result.Status == DkimVerificationStatus.Valid)
{
    Console.WriteLine("The DKIM signature is valid.");
}
else
{
    Console.WriteLine($"Verification failed: {result.Status}");
}

Remarks

DkimVerifier resolves the public key from DNS via IDkimKeyResolver. The default DkimDnsKeyResolver performs live DNS lookups; supply a custom resolver for testing or offline scenarios.