Capitol Records has brought a copyright infringement lawsuit against the startup ReDigi, which bills itself as a used digital music store.

ReDigi, which stands for “recycled digital media,” says it allows consumers to resell digital music they have bought. The company says it scans users' hard drives for proof that the music was acquired legally, and then makes a copy while deleting the original from the users' computer.

ReDigi subsequently offers to sell the “used” version to other buyers.

The company takes the position that the “first sale” doctrine gives consumers the same ability to resell digital tracks as physical CDs or vinyl records. Courts have generally said that the first sale doctrine allows people to resell lawfully products they have lawfully acquired.

But the record industry says that ReDigi's business model is unlawful.

Capitol argues in its lawsuit that ReDigi isn't selling the same tracks that users have purchased, but unauthorized copies of those tracks. “While ReDigi touts its service as the equivalent of a used record store, that analogy is inapplicable: Used record stores do not make copies to fill their shelves,” the record label argues in a lawsuit filed in federal district court in New York. “ReDigi is actually a clearinghouse for copyright infringement and a business model built in widespread, unauthorized copying of sound recordings.”

ReDigi founder John Ossenmacher counters that the case is meritless. “We will defend ... the digital rights of consumers vigorously,” he said in a statement.

But ReDigi is likely to face an uphill battle in court, predicts New York Law School professor and copyright expert James Grimmelmann. He says the “first sale” doctrine allows people to sell objects they have purchased, but not copies of those objects. “The courts have interpreted 'first sale' in ways that simply do not cover what ReDigi is doing,” Grimmelmann says.

He adds that the situation would be different if ReDigi was selling physical CDs, or even hard drives or flash drives containing digital music. But the company can't lawfully “make fresh copies, put a file on a device, or download or upload it.”

Plus, Grimmelmann says ReDigi has no way to determine whether users have made other copies of the music in their hard drives.

Capitol Records is seeking monetary damages and an injunction ordering ReDigi to stop selling the tracks it copied.