Opportunistic Encryption

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.

Opportunistic encryption can be used to combat passive wiretapping. (An active wiretapper, on the other hand, can disrupt encryption negotiation to force an unencrypted channel.) 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.