In conjunction with US copyright law, the NPL has established the following policies regarding author's rights to their works submitted to The ENIGMA:

1. All material submitted for publication in The ENIGMA remains the full property and copyright of the author. The NPL asserts and owns a copyright on its collections of works, including all issues of The ENIGMA and our web sites.
2. The NPL retains the right to reproduce submitted material in any medium whose audience is primarily NPL members or whose primary intent is NPL recruitment.
3. If the NPL wishes to reproduce submitted material in a medium whose audience is broader than listed above, it must get written permission from the author.
4. Individual authors may freely republish their own puzzles anywhere they so choose (but are asked to refrain from doing so until the solving deadlines for their puzzles have expired).