A system and method for enabling authorized music from a CD or DVD to be compressed by a user for the user's own use, but to prevent the recompression of unauthorized music from, e.g., the Internet, includes hashing the music during recording with a cryptographic hash, and then signing the hash with a digital signature derived from the hash. Subsequent unauthorized compression and recompression will destroy the digital signature. Accordingly, music to be recorded is hashed to obtain a test digital signature and if, after hashing, the test digital signature matches the digital signature accompanying the music, compression and recording are allowed to proceed.