PayPal was built to keep you secure. As a pioneer in online payments, we set the standard for fraud prevention by continuously developing and deploying a broad range of security measures so you can focus on your customers.

Fraud prevention measures.
PayPal's industry-leading loss rate is less than 0.5%. We keep sellers secure with:

•Data encryption
•Antifraud risk models
•Card Security Code (CSC)
•Verification
•Antifraud specialists
For details, go to Security for Merchants.

The PayPal security advantage.
•Security comparison. See how our security measures match up to the competition with PayPal vs. Merchant Accounts.
•Seller Protection Policy. For qualified transactions, we protect you at no additional cost with PayPal's Seller Protection Policy.
•What others are saying. Hear what fellow sellers are saying about our security in Seller Testimonials.
Other security measures.
•Confirmed address. For added protection, send items to a Confirmed Address.
•Postage and package tracking integration. For even more security when sending goods to buyers.
•Government agency partnerships. Our security teams cooperate and share investigations with the FBI and other law enforcement agencies.
•Educational resources. Including how to avoid and respond to chargebacks with our Chargeback Guide and Chargeback FAQ, and protecting yourself with the Identity Theft Guide and Tips to Sell Securely.

source :  https://www.paypal.com/hk/cgi-bin/webscr?cmd=xpt/Marketing/securitycenter/sell/SecurityForSellers-outside
 

How PayPal Protect Buyers

Privacy to Fight Identity Theft
Shop without sharing financial information with sellers. Your privacy is also safeguarded with:

•Data Encryption
•Online Safety Essentials
•Identity Protection Guide
Prevention to Help Stop Fraud
Feel secure knowing our extensive fraud-prevention programme includes:

•24/7 transaction monitoring
•Worldwide fraud specialists
•Cutting-Edge Fraud Models
•PayPal Verification System
Protection for Your Purchases
Get 100% protection against unauthorised payments sent from your account and get additional coverage for your transactions from purchase protection programmes:

•100% protection against unauthorised payments sent from your account
•Purchase Protection Programmes

Source: hthttps://www.paypal.com/hk/cgi-bin/webscr?cmd=xpt/Marketing/securitycenter/buy/Index-outside