<HTML ><HEAD ><TITLE >Physical Emissions</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="Secure Programming for Linux and Unix HOWTO" HREF="index.html"><LINK REL="UP" TITLE="Special Topics" HREF="special.html"><LINK REL="PREVIOUS" TITLE="Write Audit Records" HREF="write-audit-records.html"><LINK REL="NEXT" TITLE="Miscellaneous" HREF="miscellaneous.html"></HEAD ><BODY CLASS="SECT1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >Secure Programming for Linux and Unix HOWTO</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="write-audit-records.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 11. Special Topics</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="miscellaneous.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="PHYSICAL-EMISSIONS" ></A >11.10. Physical Emissions</H1 ><P >Although it's really outside the scope of this book, it's important to remember that computing and communications equipment leaks a lot information that makes them hard to really secure. Many people are aware of TEMPEST requirements which deal with radio frequency emissions of computers, displays, keyboards, and other components which can be eavesdropped. The light from displays can also be eavesdropped, even if it's bounced off an office wall at great distance [Kuhn 2002]. Modem lights are also enough to determine the underlying communication.</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="write-audit-records.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="miscellaneous.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Write Audit Records</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="special.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Miscellaneous</TD ></TR ></TABLE ></DIV ></BODY ></HTML >