Encrypted E-mail: Close One Door, Open Another

While e-mail encryption protects data against confidentiality and privacy attacks, encrypted e-mail messages open a new and relatively unexplored security vulnerability. Today, most popular virus scanners use a variety of techniques for detecting malicious code, but perhaps the most prevalent technique is scanning for telltale 'signatures' of known malicious code. This presents an immediate problem: the malicious code is encrypted along with the message thus the scanner will not detect malicious code if it is present. The purpose of this paper is to propose a solution that allows protection of e-mail through content encryption without compromising server-based virus scanning.