public static string GetFileSubjectValue(string fileName, string keyName)
{
X509Certificate cert = X509Certificate.CreateFromSignedFile(fileName);
Tokenizer t = new Tokenizer(cert.Subject);
while (true)
{
t.EatWhitespace();
string key = t.EatId();
if (string.IsNullOrEmpty(key))
return null;
t.EatWhitespace();
string equals = t.EatSymbol();
if (equals != "=")
return null;
t.EatWhitespace();
string value = t.EatQuotedString();
if (string.IsNullOrEmpty(value))
{
value = t.EatUntil(',');
}
if (string.IsNullOrEmpty(value))
return null;
if (key == keyName)
return value;
}
}
private static string GetX500Value(string subject, string keyName)
{
Tokenizer t = new Tokenizer(subject);
// Use the "tokenizer" to get the Common Name (CN).
while (true)
{
t.EatWhitespace();
string key = t.EatId();
if (string.IsNullOrEmpty(key))
return null;
t.EatWhitespace();
string equals = t.EatSymbol();
if (equals != "=")
return null;
t.EatWhitespace();
string value = t.EatQuotedString();
if (string.IsNullOrEmpty(value))
{
// The value probably isn't quoted.
value = t.EatUntil(',');
}
if (string.IsNullOrEmpty(value))
return null;
if (key == keyName)
return value;
string comma = t.EatSymbol();
if (comma != ",")
return null;
}
}