key4.db is an NSS key database.
The nss libraries were written and maintained by developers with Netscape, Red Hat, Sun, Oracle, Mozilla, and Google.
Authors: Elio Maldonado <email@example.com>.
Licensed under the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.