[Casimiro Noteví]

Prueba:

Código Delphi [-]
function ObtenerAliasCertificado(Cert: ICertificate): string;
var
  Subject: string;
  p1, p2: Integer;
begin
  // 1. Intentar FriendlyName
  Result := Trim(Cert.FriendlyName);

  // 2. Si no hay FriendlyName, usar SubjectName
  if Result = '' then
    Result := Trim(Cert.SubjectName);

  // 3. Intentar extraer CN= del Subject
  Subject := Result;

  p1 := Pos('CN=', Subject);
  if p1 > 0 then
  begin
    Inc(p1, 3); // saltar "CN="

    p2 := PosEx(',', Subject, p1);
    if p2 = 0 then
      p2 := Length(Subject) + 1;

    Result := Copy(Subject, p1, p2 - p1);
    Result := Trim(Result);
  end;

  // 4. Valor final de seguridad
  if Result = '' then
    Result := '(sin alias)';
end;