Abstract
Increasingly large numbers of people communicate today via electronic means such as email or news forums. One of the basic properties of the current electronic communication means is the identification of the end-points. However, at times it is desirable or even critical to hide the identity and/or whereabouts of the end-points (e.g., human users) involved. This paper discusses the goals and desired properties of anonymous email in general and introduces the design and salient features of Babel anonymous remailer. Babel allows email users to converse electronically while remaining anonymous with respect to each other and to other-even hostile-parties. A range of attacks and corresponding countermeasures is considered. An attempt is made to formalize and quantify certain dimensions of anonymity and untraceable communication.