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Started by Ruth Covington
Tue, 22 Apr 2003 22:26
CS Colloquium for Tom Lookabaugh 4/24/2003
Author: Ruth Covington
Date: Tue, 22 Apr 2003 22:26
Date: Tue, 22 Apr 2003 22:26
375 lines
17735 bytes
17735 bytes
This is a multi-part message in MIME format. ------=_NextPart_000_0046_01C308EB.E685C8D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable University of Colorado at Boulder Department of Computer Science ECOT 717 Engineering Center Campus Box 430 Boulder, Colorado 80309-0430 (303) 492-7514, FAX (303) 492-2844 CS COLLOQUIUM Multimedia and Security Selective Encryption Tom Lookabaugh University of Colorado at Boulder Thursday, 24 April 2003 3:30 - 4:30 Engineering Center Classroom 265 Refreshments will be served afterwards in ECOT 832 Most multimedia content is compressed to save on communication bandwidth = or storage; although the cost of both has declined rapidly, the cost of = computation has declined even faster so ubiquitous compression makes = sense. Moreover, much multimedia content needs to be secured for = privacy or for rights management. Increasingly, then, multimedia is = subject to both compression and encryption operations. Selective encryption leverages this now common combination; rather than = encrypt all the content, we only encrypt a small but critical fraction, = relying on the characteristics of compression algorithms to make the = remainder (in the clear) unusable. This basic idea has occurred to a = number of authors in scattered applications, including MPEG-1 video, = wireless video, MP-3 audio, and G.723 audio. But the fundamental idea = has much broader applicability, both in terms of the range of = compression and encryption algorithms that can be exploited and in terms = of functionality. =20 For example, selective encryption can be used to reduce computational = complexity, a potentially important feature in any kind of portable = multimedia application. (Indeed, this feature is likely to be important = outside of multimedia as well.) It can allow for the overlaying of = multiple security systems on a single multimedia stream with low = overhead (a commercially important application in digital television). = It can allow for efficient caching of bulk "in-the-clear" content close = to users while providing a small fraction of encrypted content at decode = time from more distant locations. =20 This presentation starts the process of building a comprehensive = theoretical basis for selective encryption (and the more general = variable encryption), and takes a cryptanalytic approach to validating = the security implications; both of these are novel contributions to the = field. The commercially important MPEG-2 algorithm is taken as a test = case and selective encryption choices and their security consequences = are experimentally analyzed. From this work, we validate the key = insight that practical high performance selective encryption will be = strongly dependent on the way in which the compressor is operated: a = cooperative compressor can yield good security even with a low fraction = of encryption, while an antagonistic compressor can easily undermine = selective encryption unless much higher fractions of the content are = encrypted (while a neutral compressor might do either). ------------------------------ http://www.cs.colorado.edu/department/events/colloquia/colloquia.html =20 Sign Language Interpreters Available Upon Request. Please contact Ruth = Covington, Department of=20 Computer Science, Engineering ECOT 717, 303-492-7514, at least five = days prior to the colloquium ------=_NextPart_000_0046_01C308EB.E685C8D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 6.00.2800.1126" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><FONT face=3DArial color=3D#000080 size=3D2> <DIV><FONT face=3DArial color=3D#000080 size=3D2><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>University of Colorado at Boulder</FONT></SPAN></DIV> <DIV> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>Department of Computer Science</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>ECOT 717 Engineering Center</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>Campus Box 430</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>Boulder, Colorado 80309-0430</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>(303) 492-7514, FAX (303) 492-2844</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3></FONT></SPAN> </P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>CS COLLOQUIUM</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3></FONT></SPAN> </P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>Multimedia and Security Selective Encryption</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>Tom Lookabaugh</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>University of Colorado at Boulder</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3></FONT></SPAN> </P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>Thursday, 24 April 2003</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>3:30 - 4:30</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>Engineering Center Classroom 265</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3></FONT></SPAN> </P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3>Refreshments will be served afterwards in ECOT = 832</FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3></FONT></SPAN> </P><SPAN=20 style=3D"COLOR: black; FONT-FAMILY: 'Times New Roman'; = mso-bidi-font-size: 12.0pt"><FONT=20 size=3D3> <P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: = normal"><SPAN=20 style=3D"FONT-SIZE: 11pt; FONT-FAMILY: 'Times New Roman'">Most = multimedia content=20 is compressed to save on communication bandwidth or storage; although = the cost=20 of both has declined rapidly, the cost of computation has declined even = faster=20 so ubiquitous compression makes sense.<SPAN style=3D"mso-spacerun: = yes"> =20 </SPAN>Moreover, much multimedia content needs to be secured for privacy = or for=20 rights management.<SPAN style=3D"mso-spacerun: yes"> = </SPAN>Increasingly,=20 then, multimedia is subject to both compression and encryption=20 operations.<?xml:namespace prefix =3D o ns =3D=20 "urn:schemas-microsoft-com:office:office" /><o:p></o:p></SPAN></P> <P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: = normal"><SPAN=20 style=3D"FONT-SIZE: 11pt; FONT-FAMILY: 'Times New Roman'">Selective = encryption=20 leverages this now common combination; rather than encrypt all the = content, we=20 only encrypt a small but critical fraction, relying on the = characteristics of=20 compression algorithms to make the remainder (in the clear) = unusable.<SPAN=20 style=3D"mso-spacerun: yes"> </SPAN>This basic idea has occurred = to a number=20 of authors in scattered applications, including MPEG-1 video, wireless = video,=20 MP-3 audio, and G.723 audio.<SPAN style=3D"mso-spacerun: yes"> = </SPAN>But=20 the fundamental idea has much broader applicability, both in terms of = the range=20 of compression and encryption algorithms that can be exploited and in = terms of=20 functionality.<o:p></o:p></SPAN></P> <P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: = normal"><SPAN=20 style=3D"FONT-SIZE: 11pt; FONT-FAMILY: 'Times New = Roman'"><o:p> </o:p></SPAN></P> <P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: = normal"><SPAN=20 style=3D"FONT-SIZE: 11pt; FONT-FAMILY: 'Times New Roman'">For example, = selective=20 encryption can be used to reduce computational complexity, a potentially = important feature in any kind of portable multimedia application.<SPAN=20 style=3D"mso-spacerun: yes"> </SPAN>(Indeed, this feature is = likely to be=20 important outside of multimedia as well.)<SPAN style=3D"mso-spacerun: = yes"> =20 </SPAN>It can allow for the overlaying of multiple security systems on a = single=20 multimedia stream with low overhead (a commercially important = application in=20 digital television).<SPAN style=3D"mso-spacerun: yes"> </SPAN>It = can allow=20 for efficient caching of bulk =93in-the-clear=94 content close to users = while=20 providing a small fraction of encrypted content at decode time from more = distant=20 locations.<o:p></o:p></SPAN></P> <P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: = normal"><SPAN=20 style=3D"FONT-SIZE: 11pt; FONT-FAMILY: 'Times New = Roman'"><o:p> </o:p></SPAN></P> <P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: = normal"><SPAN=20 style=3D"FONT-SIZE: 11pt; FONT-FAMILY: 'Times New Roman'">This = presentation starts=20 the process of building a comprehensive theoretical basis for selective=20 encryption (and the more general variable encryption), and takes a = cryptanalytic=20 approach to validating the security implications; both of these are = novel=20 contributions to the field.<SPAN style=3D"mso-spacerun: yes"> = </SPAN>The=20 commercially important MPEG-2 algorithm is taken as a test case and = selective=20 encryption choices and their security consequences are experimentally=20 analyzed.<SPAN style=3D"mso-spacerun: yes"> </SPAN>From this work, = we=20 validate the key insight that practical high performance selective = encryption=20 will be strongly dependent on the way in which the compressor is = operated: a=20 cooperative compressor can yield good security even with a low fraction = of=20 encryption, while an antagonistic compressor can easily undermine = selective=20 encryption unless much higher fractions of the content are encrypted = (while a=20 neutral compressor might do either).<o:p></o:p></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; mso-margin-top-alt: = auto; mso-margin-bottom-alt: auto"></FONT></SPAN></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; TEXT-ALIGN: center"=20 align=3Dcenter><FONT face=3DTimes color=3D#000000 size=3D3><SPAN=20 style=3D"mso-spacerun: yes"></SPAN></FONT> </P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; TEXT-ALIGN: center"=20 align=3Dcenter><B style=3D"mso-bidi-font-weight: normal"><FONT = face=3DTimes=20 color=3D#000000 size=3D3>------------------------------</FONT></B></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; TEXT-ALIGN: center"=20 align=3Dcenter><FONT face=3DTimes color=3D#000000=20 size=3D3>http://www.cs.colorado.edu/department/events/colloquia/colloquia= .html</FONT></P> <P class=3DMsoNormal=20 style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: normal; TEXT-ALIGN: center"=20 align=3Dcenter><o:p><FONT face=3DTimes color=3D#000000 = size=3D3> </FONT></o:p></P> <P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: = normal"><FONT=20 face=3DTimes color=3D#000000 size=3D3>Sign Language Interpreters = Available Upon=20 Request.<SPAN style=3D"mso-spacerun: yes"> </SPAN>Please contact = Ruth=20 Covington, Department of </FONT></P> <P class=3DMsoNormal style=3D"MARGIN: 0in 0in 0pt; LINE-HEIGHT: = normal"><FONT=20 face=3DTimes color=3D#000000 size=3D3>Computer Science, Engineering<SPAN = style=3D"mso-spacerun: yes"> </SPAN>ECOT 717, 303-492-7514, at = least five=20 days prior to the colloquium</FONT></P></DIV></FONT></FONT></DIV> <DIV><FONT face=3DArial color=3D#000080 = size=3D2> </FONT></DIV></BODY></HTML> ------=_NextPart_000_0046_01C308EB.E685C8D0-- _______________________________________________ cscolloq mailing list cscolloq@cs.colorado.edu http://www.cs.colorado.edu/mailman/listinfo/cscolloq
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