A colleague asked if it was possible to register a copyright on a work that contains trade secrets.
The issue is that when you register a copyright with the U.S. Copyright Office you generally have to provide a deposit copy of the work to be registered to the Library of Congress. And, distributing a trade secret without restriction means that it no longer remains a trade secret.
The Copyright Office provides instructions for how to handle this situation as applied to computer software. See Circular 61 (Copyright Registration for Computer Programs).
Computer Programs Containing Trade Secrets
Where a computer program contains trade secret material, include a cover letter stating that the claim contains trade secrets, along with the page containing the copyright notice, if any. Include a source code deposit as described below. The source code may be uploaded electronically with the exceptions noted above.
Entirely new computer programs
• First 25 and last 25 pages of source code with portions containing trade secrets blocked out, or
• First 10 and last 10 pages of source code alone, with no blocked out portions, or
• First 25 and last 25 pages of object code plus any 10 or more consecutive pages of source code, with no blocked out portions, or
• For programs 50 pages or less in length, entire source code with trade secret portions blocked out
Revised computer programs
If the revisions are present in the first 25 and last 25 pages, any one of the four options above, as appropriate, or if the revisions are not present in the first 25 and the last 25 pages:
• 20 pages of source code containing the revisions with no blocked out portions, or
• any 50 pages of source code containing the revisions with some portions blocked out
note: Whenever portions of code are blocked out, the following requirements must be met:
1 the blocked out portions must be proportionately less than the material remaining; and
2 the visible portion must represent an appreciable amount of original computer code.
Circular 61 at 3; See also Help: Deposit Copy.
The Copyright Office, however, does not offer any specific guidance for other works. The limited guidance that is provided pertains to requesting "Special Relief" from the deposit copy requirements. See Circular 7d (Mandatory Deposit of Copies or Phonorecords for the Library of Congress) at 4. But, such relief is discretionary and depends on a number of factors such as the acquisition policies of the Library of Congress, the examining requirements of the Copyright Office, and the hardship to the copyright owner.
Thus, you can register a copyright on a computer program containing trade secrets. However, unless you are granted Special Relief, you should not register a copyright on a non computer program containing trade secrets.