Aa!)m  0 @p   PP` 0HH $ @d HHHH̀̀̀ff@  d Footnote TableFootnote**.\t.\t/ - :;,.!?9.ceZTOCHeading1Heading2   _EquationVariablesD ;`<<=7=P=i=;B;D;F;H <$lastpagenum><$monthname> <$daynum>, <$year>"<$monthnum>/<$daynum>/<$shortyear>J<$hour>:<$minute00> <$ampm> on <$dayname>, <$monthname> <$daynum>, <$year>"<$monthnum>/<$daynum>/<$shortyear><$monthname> <$daynum>, <$year>"<$monthnum>/<$daynum>/<$shortyear> <$fullfilename> <$filename> <$paratext[Title]> <$paratext[Heading1]> <$curpagenum> <$marker1> <$marker2> (Continued)+ (Sheet <$tblsheetnum> of <$tblsheetcount>)Heading & Page <$paratext> on page<$pagenum>Pagepage<$pagenum>See Heading & Page%See <$paratext> on page<$pagenum>. Table All7Table<$paranumonly>, <$paratext>, on page<$pagenum>Table Number & Page'Table<$paranumonly> on page<$pagenum>Heading <$paratext> Number Only<$paranumonly>EHTML Headings++A335577A<<>>@@A;b;d;f;h;j;l;n;p;r;t;v;x;z;|;~;;;;;;;;;;;;;;;;;;;;;AZA\;;;;;;;;;;A~A;;;;;;;;;;;;;;;;;;;;AA;;;;;;;;;;<<<<<< < <<<<<<<<BB< <"<$<&<(<*<,<.<0<2<4<6<8<:<<BJBL<@HH  W,eH* }H ;=?H  W-eN }H ;>@H  W.eN } H ;?A H  W/a }H(;@BH(  W0e P:Numbered }HH(;ACHH(( 3eP 1e Parent = OL Q2e Depth = 0 }H(;BDH(  W4eN }H(;CEH(  W5eY } H(;DF H(  W6a }H ;EGH  W7e P:CellBody }HH ;FHHH  W8eP }H ;GIH  W9eN }H ;HJH  W:eN } H ;IK H  W;a }H ;JLH  W<eP:CellHeading }HH ;KMHH  W=eP }H ;LNH  W>eN }H ;MOH  W?eN } H ;NP H  W@a }H ;OQH  WAe P:Footnote }HH ;PRHH  WBeP }H ;QSH  WCeN }H ;RTH  WDeN } H ;SU H  WEa }H(;TVH( WFe P:Bulleted }HH(;UWHH((IeLI Ge Parent = UL QHe Depth = 0 }H(;VXH( WJeN }H(;WYH( WKeN } H(;XZ H( WLa }H ;Y[H WMe P:Heading2 }HH ;Z\HH WNeH* }H ;[]H WOeN }H ;\^H WPeN } H ;]_ H WQa }H;^`HR% P:HeadingRuPEnIn }HH;_aHH WSeP }H<`bH WTeN }H<acH WUeN } H<bd H WVa }7H <ce7H WWe P:Indented }H7H < dfH7H WXeP }7H < eg7H WYeN }7H < fh7H WZeN } 7H <gi 7H W[a }CH<hjCH\% P:TableFootPEnote }HCH<ikHCH W]eP }CH<jlCH W^eN }CH<kmCH W_eN } CH<ln CH W`a }]H(<mo]H( Wae P:TableTitle }H]H(<npH]H((deLI be Parent = OL Qce Depth = 0 }]H( H "W4a }©H(<=?©H( #W5e P:Lettered }H©H(<>@H©H((#6eLI me Parent = OL Qne Depth = 0 }©H(<?A©H( #W7eN }©H(<@B©H( #W8eN } ©H(<Ao ©H( #W9a }»d <DZF»d F$W:aHTML Options Table }D»d <DD»d F$W;a }D»d <DD»d F$W<a }D <DCGD F%W=eControl }DH <DFHDH F%W>eValue }H <DGIH F%W?e Comments }D6<DHJD6 F&W@e Image Format }DH6<DIKDH66F&A% 0001IMAGGIF p MACP0001GIEF }H6<DJLH6 F&WBa }D <DKMD F'WCeBanners }DH <DLNDH F'WDeN }H <DMOH F'WEa }D<DNPDF(F% Banner ReferPE ence Frame }DH<DOQDH F(WGe }H<DPRH F(WHa }D(<DQSD((F)I$% Copy Files  Imported by PE Rerefernce }DH(<DRTDH( F)WJe }H(<DSUH( F)WKa }DD(<DTVDD((F*L% Copy Files  Imported by PE Reference }DDH(<DUWDDH( F*WMeN }DH(<DVwDH( F*WNa }Vd <Dv[Vd F+WOaSystem Macros }?Vd <D?Vd F+WPa }Vd <DVd F+WQa }f? <DX\f? F,WRe Macro Name }?fH <D[?fH F,WSe Replace With }fH <D^fH F,WTe Comments }r? =D]_r? F-WUe StartOfDoc }?rH =D^?rH F-WVa }rH =DarH F-WWa }~? =D`b~? F.WXe EndOfDoc }?~H = DaR?~H F.WYa }~H = DRd~H F.WZa }?= Dce?F/[% StartOfSubPEDoc }?H=DdS?H F/W\a }H=DSgH F/W]a }?=Dfh?F0^% EndOfSubPEDoc }?H=DgT?H F0W_a }H=DTjH F0W`a }?=Dik?F1a% StartOfFirstPESubDoc }?H=DjU?H F1Wba }H=DUmH F1Wca }?=Dln?F2d% EndOfFirstPESubDoc }?H=!DmV?H F2Wea }H=#DVpH F2Wfa }?=%Doq?F3g% StartOfLastPESubDoc }?H='DpW?H F3Wha }H=)DWsH F3Wia } ?=+Drt ?F4j% EndOfLastPESubDoc }? H=-DsX? H F4Wka } H=/DXy H F4Wla }HC*D_wHF5go% X:Number EOnly }HC,DvxH F5G^e See Also }HC.DwYH F5G_eN },d =8Du|,d F6WpaCross-Reference Macros }?,d =:D?,d F6Wqa },d =<D,d F6Wra }<? =>Dy}<? F7Wse Macro Name }?<H =@D|~?<H F7Wte Replace With }<H =BD}<H F7Wue Comments }H?=DD~H? F8Wve See Also }?HH=FD?HHF8w% See Also: PE <$paratext> }HH=HDHH F8Wxa }Vd @pDVd F+Wye }fH @rD\]fH F,WzeHead }rH @tD_`rH F-W{e }hd =QD hd F:WaGeneral Macros }?hd =SD?hd F:Wa }hd =UDhd F:Wa }hd =WDhd F:Wa }x? =YD"x? F;We Macro Name d= d= d l d= du  WBm }d = d  <W|aHeadings Table }Hd = Hd  <W}a }Hd = Hd  <W~a }H= H  =WeHeading Level }HH= HH =%Paragraph ForPEmat }H= H  =We Comments }H= H >W e2 }HH= HH  >We Heading1 }H= H  >Wa }KH = KH  ?We3 }HKH = HKH  ?We Heading2 }KH = KH  ?Wa }WH = WH  @We4 }HWH = HWH  @W e Lettereda }WH = WH  @W a }cH= cH  AW e1 }HcH= HcH AW eTitle }cH= cH  AW a }?H ?D ?H FBWDe... }H ?DH FBWEe }? ?DH8? FGWFe }?xH =[D #?xH F;We Replace With }xH =]D"$xH F;W eHead }xH =_D#%xH F;W!e Comments }? =aD$&? FCW"a }?H =cD%'?H FCW#a }H =eD&(H FCW$a }H =gD')H FCW%a }d =jD(.d FDW&aCharacter Macros HHˆ;"HHˆ+Ge HHˆ;$3HHˆ**l}?d =lD?d FDW'a }d =nDd FDW(a }? =pD)/? FEW)e Character }?H =rD.0?H FEW*e Replace With }H =tD/1H FEW+e Comments }? =vD0B? FFW,e HUV ;.HUV 3Ge HUV ;05+HUV 22l H$ ;1H$ 5Ge H$ ;33H$ 44l HHˆ;4HHˆ!%%7 ` Homework 3 G `Due Date : May 3, 2001 :`Points : 100 H` !0 n( 20 points ; text, exercise 5.2)  Given the security levels TOPSECRET, SECRET, CONFIDENTIAL, and nUNCLASSIFIED (ordered from highest to lowest), and the categories A, B, and C, say what type of access (read, qwrite, or both) is allowed in the following situations. Assume discretionary access controls allow anyone access @unless otherwise specified. =`cPaul, cleared for (TOPSECRET, { A, C }), wants to access a document classified (SECRET, { B, C }). !> bAnna, cleared for (CONFIDENTIAL, { C }), wants to access a document classified (CONFIDENTIAL, { B @}). ?`aJesse, cleared for (SECRET, { C }), wants to access a document classified (CONFIDENTIAL, { C }). !@ cSammi, cleared for (TOPSECRET, { A, C }), wants to access a document classified (CONFIDENTIAL, { A @}). !A bRobin, who has no clearances (and so works at the UNCLASSIFIED level), wants to access a document @"classified (CONFIDENTIAL, { B }). 䪛 |( 20 points ; text, exercise 6.5) Explain why the system controllers in Lipners model need clearances of (SL, { D, @PC, PD, SD, T }).  t( 20 points ; text, exercise 7.4) Consider using mandatory access controls and compartments to implement an 0 ORCON control. Assume there are  k  different organizations. Organization  i  will produce  n ( i , j ) documents to be @&shared with organization  j . ! gHow many compartments are needed to allow any organization to share a document with any other organiza@tion? 5* JNow assume that organization  i  will need to share  n m ( i ,  i 1 , ,  i m ) documents with organizations  i 1 , ,  i m . UUL@&How many compartments will be needed? 1^`G( 20 points ; text, exercise 9.11) Please prove the following: 2j`EIf  p  is a prime,  f ( p ) =  p 1. 3`kIf  p  and  q  are both prime,  f ( pq ) = ( p 1)( q 1). 4`r( 20 points ; text, exercise 11.6) Needham and Schroeder suggest the following variant of their protocol: 6`Alice    Bob : Alice 7*`GBob    Alice : { Alice,  rand 3  }  k Bob 8U2`tAlice    Cathy : { Alice, Bob,  rand 1 , { Alice,  rand 3  }  k Bob  } 9`5Cathy    Alice : { Alice, Bob,  rand 1 ,  k session , {Alice,  rand 3 ,  k session }  k Bob  }  k Alice ;``Alice    Bob : { Alice,  rand 3 ,  k session  }  k Bob <`DBob    Alice : {  rand 2  }  k session B`EAlice    Bob : {  rand 2 1 } k session ICUU`QShow that this protocol solves the problem of replay due to stolen session keys. HHˆ;6HHˆ66 l}?H ?D!9?H FGWIe- }H ?D8H FGWJe }? @DKG? FHWKe d;;<@H$ ;<;>H$ == l H$ ;=;H$ <Wl6April 19, 2001ECS 253 Spring 2001Page 1  HUV ;>;<@HUV ?? l HUV ;?;HUV >WlBLast modified at  11:09 pm on Wednesday, April 18, 2001  HHˆ;@;>HHˆAA l HHˆ;A;HHˆ@W` }?H =xD1C?H FFW-e¢ }H =zDBOH FFW.a d=~EEd=DdFF l d=Dd$[ E$[vCFILORUwtX[^adgjmpsy| %).1OLI:!}?H @D:H?H FHWLe-- }H @DG!H FHWMe }? @DNJ? FIWNe }?H @DIK?H FIWOe° }H @ DJ:H FIWPe }? @ DQM? FJWQe }?H @DLN?H FJWRe® }H @DMIH FJWSe }? @DCP? FKWTe }?H @DOQ?H FKWUe© }H @DPLH FKWVe }~H @vDbc~H F.WWe }H@xDefH F/WXe }H@zDhiH F0WYe }H@|DklH F1WZe }H@~DnoH F2W[e }H@DqrH F3W\e } H@Dtu H F4W]e }HC0DxZH F5G`eN }HC2DYCH F5Gae }H C4D\H F9Gbe C:Symbol }H C6D[]H F9GceEM }H C8D\^H F9GdeN }H C:D]_H F9GeeN }H C<D^vH F9Gfe }H C>iaH LGgeC:Fixed }H C@`bH LGheEM }H CBacH LGieN }H CDbdH LGjeN }H CFcH LGke }H CHnfH MGle C:Emphasis }H CJegH MGmeEM }H CLfhH MGneN }H CNgiH MGoeN }H CPh`H MGpe }H CRskH NGqeP:Line }H CTjlH NGreP }H CVkmH NGseN }H CXlnH NGteN }H CZmeH NGue }H C\BpH OGve P:Lettereda }H C^oqH OGweH* }H C`prH OGxeN }H CbqsH OGyeN }H CdrjH OGze }DCDyuDFPg{% CSS Export E Encoding }HCDtvH FPG|e }HCDuXH FPG}e }DCDWxDFQg~% Export EnEcoding }HCDwyH FQGe }HCDxtH FQGe dLeftd;Rightd ReferenceddHTMLdDHTMLd Headings @@ `Mapping Table Title. @@ `Body.  f@P`TitleBody. f@E ` Numbered1.\tNumbered. @@ `Footer. f@T ` TableTitleT:Table : . @@ `Mapping Table Cell. f@ `. Body. @@` Mapping Table Cell. f@ `Body. @@ `Header Double Line. f@ ` CellFooting. f@ ` CellHeading. f@ ` CellBody. @@ `Mapping Table Cell. $f@NE `$. Lettered N:< >. Numbered-. @@9Mapping Table Cell. $f@NE `$. Lettered N:< >. Numbered-. @@ 9Mapping Table Cell. @@ `Mapping Table Cell. f@ `Body. f@ ` Indented. $f@NE `$. Lettereda N:< >. Numbered-. $f@NE `$. Lettereda N:< >. Numbered-. f@ ` BodySpaced. f@ ` Bulleted\t. f@ `...Date. mf@ `l. DateProject. @@ `Header Double Line. f@T `Heading1Body. f@ ` NumberedSpaced. f@E ` Numbered1.\tNumbered. f@ `.Reading.  f@P`TitleBody. f@$`.Line Single Line. f@ `CellBody. f@ ` CellHeading. f@ ` Footnote. f@T `Heading2Body. f@T ` HeadingRunInBody. f@ ` TableFootnote. f@T ` TableTitleT:Table : . f@ ` Numbered.\t. f@ ` Numbered.\t. f@ ` NumberedSpaced.  ` `` ` 9 ` ڝ``Emphasis ` \ Symbol``EquationVariables ڝ` 9  BoldItalic `Italic `Bold `9 ` ` ` \ Symbol ` # FixedZZThinMediumDoubleThick@ Very Thin HHHHHFormat AH Mapping Table HHHHHFormat BH Mapping Tableh65HHHHH$PDHH+4?HHH68?HH :C?HHHTDB?HH*< ? @ h( A B C D E h  F G H I J h  K L M N O h  P Q R S T h( UVWXYh Z[\]^h_`abc7h defghChijklm]h(nopqrh stuvwh xyz{|h(}~h h    h  h h h)h  !"#$5h%&'()Oh  *+,-.[h!/ 0 1 2 3 uh "4!5!6!7!8!h!#9":";"<"="©h("O>#?#@#A#B#» %FC$D$E$ $&FF%G%H%6%'FI&J&K& &(FL'M'N'')FO(P(Q(((*FR)S)T)D()QFU*V*W*Vd ,FX+Y++Z+f +-F[,\,,],r ,.F^-_--`-~ -/Fa.b.R.c..0Fd/e/S/f//1Fg0h0T0i002Fj1k1U1l113Fm2n2V2o224Fp3q3W3r3 3Fs4t4X4u4h9Fv5w5x5Y5Z5,d 7Fy6z6{6< 68F|7}7~7H7F888h L5F[9\9]9^9_9hd ;F::::x :CF ;";#;$; =  <<<<> ====? >>>K >@ ???W ?A @@@c@ AAA GFBB B ;F%C&C'C(Cd EF)D,D-D DFF.E/E0E EKF1FBFCF HBF!G8G9G IGF:HGHHH JHFIIJIKI KIFLJMJNJ FJFOKPKQKh M9`LaLbLcLdLh NLeMfMgMhMiMh OMjNkNlNmNnNh #NoOpOqOrOsOQFtPuPvP*PFwQxQyQComment ;C ;Gd BlackT!WhiteddARedddGreendd BluedCyandMagentad YellowHeader/Footer $1Header/Footer $1Header/Footer $2Header/Footer $2IndexIndexCommentCommentSubjectSubjectAuthorAuthorGlossaryGlossaryEquationEquation Hypertext Hypertext  Cross-Ref Cross-Ref Conditional TextConditional TextPositionFMPrivatePositionFMPrivateRangeEndFMPrivateRangeEndFMPrivate HTML Macro HTML Macro M.Times.P Times-Roman FrameRoman M.Times.B Times-Bold FrameRoman M.Helvetica.BHelvetica-Bold FrameRoman M.Symbol.PSymbol FrameRomanM.Helvetica.BIHelvetica-BoldOblique FrameRoman M.Times.I Times-Italic FrameRoman M.Courier.PCourier FrameRomann"Courier8 Helvetica[Symbol_Times#Regular$Roman MediumBoldRegular ObliqueItalic}"6%jDbݖ鹤_"d1xVYdk{w/rѴ:cPp„zD2'j~';[#EY>б8e! >[ hlQ{h:HYWR60!Pq=slֺ