Docker
Copyright 2012-2013 dotCloud, inc.

This product includes software developed at dotCloud,
inc. (http://www.dotcloud.com).

This product contains software (https://github.com/kr/pty) developed
by Keith Rarick, licensed under the MIT License.

Transfers of Docker shall be in accordance with applicable export
controls of any country and all other applicable legal requirements.
Docker shall not be distributed or downloaded to or in Cuba, Iran,
North Korea, Sudan or Syria and shall not be distributed or downloaded
to any person on the Denied Persons List administered by the U.S.
Department of Commerce.

What does that mean? 
Here is a further explanation from our legal counsel:

Like all software products that utilize cryptography, the export and
use of Docker is subject to the U.S. Commerce Department's Export
Administration Regulations (EAR) because it uses or contains
cryptography (see
http://www.bis.doc.gov/index.php/policy-guidance/encryption).  Certain
free and open source software projects have a lightweight set of
requirements, which can generally be met by providing email notice to
the appropriate U.S. government agencies that their source code is
available on a publicly available repository and making the
appropriate statements in the README.

The restrictions of the EAR apply to certain denied locations
(currently Iran, Sudan, Syria, North Korea, or Cuba) and those
individuals on the Denied Persons List, which is available here:
http://www.bis.doc.gov/index.php/policy-guidance/lists-of-parties-of-concern/denied-persons-list.
If you are incorporating Docker into a new open source project, the
EAR restrictions apply to your incorporation of Docker into your
project in the same manner as other cryptography-enabled projects,
such as OpenSSL, almost all Linux distributions, etc.

For more information, see http://www.apache.org/dev/crypto.html and/or
seek legal counsel.