The security of your information, transactions, and money is the core of Paypal and there top priority.
PayPal automatically encrypts your confidential information in transit from your computer to there's using the Secure Sockets Layer protocol (SSL) with an encryption key length of 128-bits (the highest level commercially available). Before you even start your transactions, there server checks that you're using an approved browser - one that uses SSL 3.0 or higher.
Once your information reaches PayPla, it resides on a server that is heavily guarded both physically and electronically. There servers sit behind an electronic firewall and are not directly connected to the Internet, so your private information is available only to authorized computers.