The process of sending data over a network in an unencrypted form. By using a packet sniffer or software such as Network Monitor, anyone who can capture clear-text packets can read the information within them.
Clear-text authentication methods are sometimes the best choice in a heterogeneous network environment where users running different operating system platforms need to access resources on network servers.
For example, UNIX clients that need to access an Internet Information Services (IIS) machine using a Web browser will need to be authenticated using a clear-text method called Basic Authentication.
Basic Authentication is usually described as clear-text authentication, but in actuality, Basic Authentication weakly encrypts data using the well-known uuencoding algorithm. This algorithm is in the public domain and can easily be decrypted by knowledgeable users.
The standard AppleTalk protocol uses clear-text authentication for allowing Macintosh clients to access shared folders on Macintosh file servers using AppleShare.