Significant effort has been contributed to the security of POP Peeper. Here's a list of the security-related features:

• Passwords and other sensitve information are encrypted using well-established encryption algorithms
• Two methods of password protection allow you to protect individual accounts and\or access to the main interface
• Support for SSL, TLS and APOP encrypt data when using mainstream protocols
• Methods for detecting tampering of passwords and other sensitive data are used to help protect the data
• All data can be stored on a portable device so no data will be left behind when you leave the computer
• Many options are provided for reading your email, including conversion to plain text, removing images and data stored on another server, and more

See also: How can I ensure POP Peeper is as secure as it can be?