In a letter to Apple to Apple CEO Tim Cook, U.S. Sen. Al Franken questions how the company plans to safeguard the privacy of customers who buy the new iPhone 5S, which includes a fingerprint reader.
Franken wants to know if it's possible to obtain fingerprint data from the iPhone, either remotely or with access to the device.
Franken's also questioned what Apple has done to ensure that the fingerprint data is secure and whether the company can assure users that it will not share or sell fingerprint files with third parties.
Analysts predict Apple will sell at least 5 million of the devices this weekend.
"Passwords are secret and dynamic; fingerprints are public and permanent," Franken wrote.
"You can't change your fingerprints. You only have ten of them. And you leave them on everything you touch; they are definitely not a secret. What's more, a password doesn't uniquely identify its owner -- a fingerprint does. Let me put it this way: if hackers get a hold of your thumbprint, they could use it to identify and impersonate you for the rest of your life."
Here's a copy of the letter Franken sent to Cook: