Opportunistic Encryption: Encryption, Telephone Tapping, Openswan, OpenWrt, Linksys WRT54G Series, FreeS/WAN, Domain Name System, OpenVPN

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Opportunistic Encryption (OE) refers to any system that, when connecting to another system, attempts to encrypt the communications channel otherwise falling back to unencrypted communications. This method requires no pre-arrangement between the two systems. It is sometimes described as "Better Than Nothing Security" or ANONSEC (anonymous security). Opportunistic encryption can be used to combat passive wiretapping. It does not provide a strong level of security as authentication may be difficult to establish and secure communications are not mandatory. Yet, it does make the encryption of most internet traffic easy to implement, which removes a significant impediment to the mass adoption of Internet traffic security.