/*
* see http://www.dkim.org/specs/rfc4871-dkimbase.html#dkim-sig-hdr
*
* */
public string GenerateDkimHeaderValue(Email email, List <EmailHeader> headers)
{
// timestamp - seconds since 00:00:00 on January 1, 1970 UTC
var t = DateTime.Now.ToUniversalTime() - DateTime.SpecifyKind(DateTime.Parse("00:00:00 January 1, 1970"), DateTimeKind.Utc);
var signatureValue = new StringBuilder();
const string start = " ";
const string end = ";";
signatureValue.Append("v=1;");
// algorithm used
signatureValue.Append(start);
signatureValue.Append("a=");
signatureValue.Append(_privateKeySigner.Algorithm);
signatureValue.Append(end);
// Canonicalization
signatureValue.Append(start);
signatureValue.Append("c=");
signatureValue.Append(HeaderCanonicalization.ToString().ToLower());
signatureValue.Append('/');
signatureValue.Append(BodyCanonicalization.ToString().ToLower());
signatureValue.Append(end);
// signing domain
signatureValue.Append(start);
signatureValue.Append("d=");
signatureValue.Append(_domain);
signatureValue.Append(end);
// headers to be signed
signatureValue.Append(start);
signatureValue.Append("h=");
foreach (var header in headers)
{
signatureValue.Append(header.Key);
signatureValue.Append(':');
}
signatureValue.Length--;
signatureValue.Append(end);
// i=identity
// not supported
// l=body length
//not supported
// public key location
signatureValue.Append(start);
signatureValue.Append("q=dns/txt");
signatureValue.Append(end);
// selector
signatureValue.Append(start);
signatureValue.Append("s=");
signatureValue.Append(_selector);
signatureValue.Append(end);
// time sent
signatureValue.Append(start);
signatureValue.Append("t=");
signatureValue.Append((int)t.TotalSeconds);
signatureValue.Append(end);
// x=expiration
// not supported
// hash of body
signatureValue.Append(start);
signatureValue.Append("bh=");
signatureValue.Append(SignBody(email));
signatureValue.Append(end);
// x=copied header fields
// not supported
signatureValue.Append(start);
signatureValue.Append("b=");
return(signatureValue.ToString());
}
public MailHeader CreateHeader(IEnumerable <MailHeader> headers, string body, DateTime date)
{
var _headers = headers
.Where(h => required_headers.Contains(h.Key.Trim().ToLower()))
.ToArray();
TimeSpan t = date -
DateTime.SpecifyKind(DateTime.Parse("00:00:00 January 1, 1970"), DateTimeKind.Utc);
var value = new StringBuilder();
const string start = " ";
const string end = ";";
value.Append("v=1;");
// algorithm used
value.Append(start);
value.Append("a=");
value.Append(GetAlgorithmName());
value.Append(end);
// Canonicalization
value.Append(start);
value.Append("c=");
value.Append(HeaderCanonicalization.ToString().ToLower());
value.Append('/');
value.Append(BodyCanonicalization.ToString().ToLower());
value.Append(end);
// signing domain
value.Append(start);
value.Append("d=");
value.Append(Domain);
value.Append(end).Append(Keyword.CRLF);
// headers to be signed
value.Append(start);
value.Append("h=");
foreach (var header in _headers)
{
value.Append(header.Key.ToLower());
value.Append(':');
}
value.Length--;
value.Append(end).Append(Keyword.CRLF);
// public key location
value.Append(start);
value.Append("q=dns/txt");
value.Append(end);
// selector
value.Append(start);
value.Append("s=");
value.Append(Selector);
value.Append(end);
// time sent
value.Append(start);
value.Append("t=");
value.Append((int)t.TotalSeconds);
value.Append(end);
// hash of body
value.Append(start);
value.Append("bh=");
value.Append(SignBody(body));
value.Append(end).Append(Keyword.CRLF);
value.Append(start);
value.Append("b=");
var x = new MailHeader(HeaderName.DkimSignature, value.ToString());
x.Append(SignHeaders(_headers, x));
return(x);
}
