sentences:  It held that Quaid's software was not a derivative work of Vault's software, despite having approximately 30 characters of source code in common.Finally, it held that the Louisiana Software License Enforcement Act clause permitting a copyright holder to prohibit software decompilation or disassembly was preempted by the Copyright Act, and was therefore unenforceable.Vault Corporation created and held the copyright for a program called PROLOK, which provided copy protection for software on floppy disks.