dnscrypt-proxy is covered by the following license :

/*
 * Copyright (c) 2011-2015 Frank Denis <j at pureftpd dot org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

====

This license applies to all parts of dnscrypt-proxy that are not externally
maintained libraries.

The externally maintained libraries used by dnscrypt-proxy are:

  - libsodium (https://github.com/jedisct1/libsodium). 2-clause BSD
    license. Based on NaCl (http://nacl.cr.yp.to), public domain. See
    src/libsodium/{COPYING,AUTHORS}.

  - libevent (http://libevent.org/). 3-clause BSD license.
    See src/libevent/LICENSE.