Selected File: Pretty Good Privacy Encryption Software by PGP Corporation
available versions :
PGP v9.0x Trial Release
PGP is a powerful cryptographic software suite that enables people to securely exchange messages, and to secure files, disk volumes and network connections with both privacy and strong authentication. By providing the ability to encrypt messages, PGP provides protection against anyone eavesdropping on the network. Even if the information is intercepted, it is completely unreadable to the snooper. Authentication identifies the origin of the information, certainty that it is authentic, and that it has not been altered. In addition to secure messaging, PGP also provides secure data storage, enabling you to encrypt files stored on your computer. 30 days trial with a personal licence send to your email by PGP corporation.
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Here are FAQ for PGP
Here is a study of secure deletion of data from RAM and magnetic media
Here is encryption security info
http://www.pgp.com/downloads/index.html