Vault Corp v. Quaid Software Ltd.
United States Court of Appeals for the Fifth Circuit
847 F.2d 255 (1988)
Vault Corporation (Vault) (plaintiff) manufactured PROLOK disks designed to prevent unauthorized software copying by embedding an irremovable disk fingerprint that PROLOK software checked before running; software producers installed their own programs onto Vault's PROLOK disks. Quaid Software Limited (Quaid) (defendant) sold RAMKEY, a program letting users circumvent PROLOK by fooling the software into recognizing disk copies as containing the genuine fingerprint, allowing users to make fully functional copies of PROLOK-protected programs. Vault sued for copyright infringement seeking an injunction against Quaid's use and sale of RAMKEY; the district court found for Quaid, holding RAMKEY authorized under § 117 of the Copyright Act, and Vault appealed.
Whether the owner of a computer program is permitted to make unauthorized copies of the program if the copies are necessary to use the program.