O
`Ufllted States Patent
`
`[19]
`
`[11] Patent Number:
`
`4,613,901
`
`Gilhousen et al.
`[45] Date of Patent:
`Sep. 23, 1986
`
`
`
`
`.
`3/1982 Saeki et al.
`4,322,745
`4/1982 Guillou .............
`4,323,921
`2,338,922 4/1982 den_Toonder et a1.
`4~33,’g;,3,
`Ej,‘,‘,‘;‘,,f:,,*‘:,-1-1--------
`353/120
`4,336,553
`6/1982 den Toonder et al.
`353/120
`4,338,628
`7/1932 Payne et al.
`......
`358/122
`4,354,201 10/1982 Sechet et al.
`..
`64
`.
`358/122
`4,388,
`3
`6/1983 Amuietzah ........
`178/22.16
`4,458,109
`7/1984 Mueller-Schloer
`455/4
`4,461,032
`7/1984 Skerlos
`
`43:72:11
`21:21-12: 2:122: 4:,:*:;r
`358/122
`......
`4,484,027 l1/1984 Lee et a1.
`178/22.08
`4,531,011
`7/1985 Bluestein et al.
`. 178/22.08
`4,531,020 7/1985 Wechselber er et al.
`8/12
`4533 948
`8/1985 M N
`g
`1
`35
`2
`,
`,
`c
`t
`.
`358,122
`4,533,949 3,198, F,,,~,,,,a,:?:’:,e,f_
`4,535,355
`8/1985 Arnetal. .......................... .. 358/122
`.
`.
`.
`.
`fi”’,”‘”J’ %‘“’""_"”—§‘,’,~“P,1,‘e‘}Cv-VB“°Z1“5k‘
`,i:::::::$ ,:;:;’:'"::;;,-,1,“ :sw;;‘::e C11,,
`[57]
`ABSTRACT
`
`358/123
`358/114
`358/l 17
`
`1
`
`[54] S[GNAL ENCRYPTION AND
`DISTRIBUTION SYSTEM FOR
`CONTROLLING SCRAMBLING AND
`SELECIIVE REMOTE DESCRAMBLING or
`TELEVISION SIGNALS
`Inventors: Klein S. Gilhousen, San Diego;
`_
`-
`Charles F. Newby, Jr., El Ca_1on, Karl
`E Moerder Poway all of Calif
`°
`9
`’
`'
`[73] Assignee, M/ Linkabit Inc, San
`’
`’
`
`[75]
`
`[21] APP1, No,, 493,309
`' 22
`Filed:
`May 27, 1983
`[51]
`int. cw ........................ H04N 7/167; H04L 9/oo
`[52] U.S.Cl. ............................... .. 358/122; 178/22.07;
`178/22.1; 178/22.16
`[58] Field of Search ..................... 353/122; 178/22.07,
`
`[56]
`
`References Cited
`
`A system and method for scrambling and selectively
`descrambling television signals that are transmitted to
`subscribers’ descramblers in a subscription television
`system. A working key signal is generated by process-
`ing an “initialization vector” signal in accordance with
`t1.‘,,e,,DES algomhmtupon til’: a1g°ri;1hm being k‘;,"°dkby
`6.‘ er 3 °°m.m°” Ca egm?’ Cy mg“
`°’ .S°‘“° °t 6’ ey
`signal.
`unique ,e,nc,ryp,tion keystream is generated by
`processing the initialization vector signal in accordance
`with the DES algorithm upon the algorithm being
`keyed by the working key signal. A television signal is
`scrambled in accordance with the unique encryption
`'
`‘
`'
`'
`kfystfiamfto imvlde 2‘ Sirimblted te]°1‘:‘S‘°’.‘ s‘g1"a.1'd’.°‘
`p.““” 3' ° ““‘‘‘“° encryp. ° °‘’ °g°’y ey 513"“ S.” ",
`vidually addressed to different selected subscribers
`descramblers are generated by processing the, initial
`common category key signal in accordance with the
`DES algorithm upon the algorithm being keyed by a
`plurality of different “unit key” signals unique to differ-
`ent selected descramblers. The scrambled television
`signal, the initialization vector signal, and the plurality
`of encrypted category key signals are broadcast to the
`descramblers. A corresponding tier of DES algorithms
`are employed at the descrambler to reproduce the en-
`.
`.
`.
`cryption keystream; and the TV signal 1S descrambled
`.
`h
`. h
`h
`.
`in,accord,ance
`erewit
`.
`l:?ac
`descrambler has its
`unique unit key signal stored in a secure memory for use
`in reproducing the common category key signal when
`the descrambler is addressed by its unique encrypted
`°‘“°g°‘y *7 “W1-
`26 Claims, 8 Drawing Figures
`SCRAIIILEI
`scnmaizo ‘n
`SIGNAL
`rnanzsson
`
`
`,,
`41163125,, 7/1979 B,
`, ,1,
`4’163’255
`7/1979 Pigs ‘’
`’
`’
`"""""""
`.. 178/22
`4,172,213 10/1979 Barnes et al
`.
`358/124
`4,215,366 7/1980 Davidson ..
`358/122
`4,225,884 9/1080 B1oCkcta1_
`358/122
`4,250,524 2/1931 -1-omizawa _
`_. 353/114
`4,253,114
`2/1981 Tang et a1,
`358/123
`4,292,650
`9/1981 Hendrickson .
`"2§§%§S
`1’§8Z’ZZé 152331 ‘i'?;%‘“‘
`,
`,
`3. ....
`4,316,055
`2/1982 Feistal ............................ .. 178/2206
`
`
`
`1-.514:-unou uuuszn
`
`CDIHROL
`
`:m,u,“
`
`
`
`izruu: COUNT
`
`I9
`
`nusnmiunun
`ensaour xiv
`Sm,“
`ruenv-no cnzaonxzvs
`sunscmzn monassrs
`I!
`
`sulsemnzn xzvs
`I4
`
`
`
`PMC Exhibit 213
`
`Apple v. PM
`IPRZO16-0075
`
`Page 1
`
`U-S- PATENT DOCUMENTS
`3,233,297
`3/1965 pawley at 31,
`_
`3,668,307
`6/1972 Face et a1.
`_
`3,729,581
`4/1973 Anderson
`1:’; ,‘:Vl,“,1g, at 31
`3:8o3’:49i 4/1974 ozifoiniii
`5/1975 Kosoo
`3,886,302
`3,894,170 7/1975 Mellon _________,
`3,399,533
`3/1975 so,-enson et 31,
`3,916,091 10/1975 Kirk, Jr. et al.
`3,919,462 11/1975 Hartung et al.
`lg; £_aIr,:>I1,:>n,e,t,,a1-
`,
`,
`10 C
`C
`.
`4,024,574 5/1977 Nieson .......
`4,025,942
`5/1977 Loshin
`4,058,830 11/1977 Gums, et 31
`4,068,264
`1/1978 Fires
`4,091,417
`5/1973 Nieson
`4,112,454 9/1973
`'
`4,115,662 9/1978
`4,1l5,807 9/1978
`
`,
`..
`
`173/22
`173/5,6
`178/6.8
`
`~
`I 325/53
`.
`l78/5.1
`_ 178/5_1
`, 173/5,1
`_ 173/5,1
`. 178/5.1
`~
`.....
`
`.
`358/117
`.. 353/122
`______ 358/86
`358/122
`__ 357/117
`353/122
`179/15 BV
`358/122
`
`-- 178/22
`353/114
`
`
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 1
`
`

`
`U.S. Patent
`
`Sep. 23, 1986
`
`Sheet 1 of8
`
`4,613,901
`
`.5omjmzqmom
`
`c.u._m2<mum
`
`._<zo_m
`
`mommmooma
`
`ON
`
`SE28mmwoomm.
`
`
`
`mwmzszzo:<Ezmo
`
`5;mum_Eomm:m
`
`
`
`
`
`m.#2300m_2<EH
`
`
`
`
`
`Exdzz<:oowEEozwmfimmmmommmmmogE0820
`
`
`
`
`
`
`
`
`
`.mmm;Eoontqoourcéozuzo_<_‘.w.%..m5_oExEo82o
`
`
`
`
`
`\Mu»;
`
`m
`
`
`
`_mummmmoo<mmm_momm:m
`
`
`
`mxmxmmm_momm:m
`
`._oEzoo
`
`mmtisou
`
`PMC Exhibit 213
`
`Apple v. PM
`|PR2016-0075
`
`‘
`
`Page
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 2
`
`
`
`
`
`
`
`
`
`

`
`U.S. Patent
`
`Sep.23,1986
`
`Sheet2of8
`
`4,613,901
`
`cozqmmpmywx
`
`2<mm»m>mx
`
`mok<mmzmo
`
`»mz
`
`oz_xmo3
`
`4mzz<:u
`
`ow»a>muzw
`
`«w
`
`m»<uz:m»
`
`mm
`
`4mzz<:o
`
`>mx
`
`>mx
`
`ov
`
`mop<mmzmo
`
`fin
`
`on
`
`vo
`
`«o
`
`on
`
`mm
`
`oz<axm
`
`ozimoa
`
`>ux
`
`mokqmmzmo
`
`mm
`
`O
`r0
`
`V
`LD
`
`¢N
`
`oz<uxu
`
`<1‘N
`
`m_Hzsoo
`
`H
`
`mz<mu
`
`mwmu>mmm
`
`om»a>mozm
`
`>moou»<o
`
`>m¥
`
`mmvm
`
`»moowh<o
`
`rmx
`
`mo»<muzmo
`
`¢w
`
`mm
`
`mm
`
`M
`n
`
`ozqaxm
`
`¢m
`
`pm
`
`mm
`
`¢o
`
`mm
`
`oz<¢xm
`
`vn
`
`¢w
`
`mu
`
`oz<mxu
`
`
`
`mermx
`
`mm
`
`4wzz<:u
`
`9
`
`
`
`w.mmwmoo<
`
`»moom»<u
`
`mm»moom»<u
`
`
`
`m.>ux
`
`mm
`
`m.mmm_mumm:m
`
`mmmum_mumm:m
`
`mummmmooa
`
`mrmx
`
`312HWh.XECMD:
`
`.0D|v5W10mmP
`M5e
`Pmw
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 3
`
`
`
`
`
`
`

`
`P
`
`1
`
`1|.6
`
`’
`
`1
`
`oz»mmmmhzaooe.zoioufioSm.GP.‘
`
`
`
`
`
`
`
`39msmoo9:“.Jmmmmooq
`
`.%Etnam2...
`_6Ejogzoo
`
`5.
`
`
`
`ommmooq
`
`t
`
`
`
`.....So%mm
`
`o\<.PozE<:mm><;uz:89>8.nome89>ab.pmmmmmmmon
`amm._.._EE0222.Sham
`
`
`
`
`
`
`
`omSE28mmmoomaE03566B._m2<5mmmSE28o¢Ex._uzz<:oom:&&ozn.__wmoimmzmwm_pzzoum2<EH%.
`
`
`mommmoomn.9mmmmooq EmiommammmSmotxmzmommmm;>moem:<oSirmozm05<3x:s_mozumfim“mm.3s_<uEw»uv_252,52zofiamzmoEv.
`
`
`
`
`
`
`
`
`49zotxmzuo
`
`255$
`
`%,mommmuomn.
`
`3oapqmvo_n5<
`
`PMC Exhibit 213
`
`Apple v. PM
`|PR2016-0075
`
`Page
`
`
`
`
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 4
`
`
`

`
`U.S. Patent
`
`Sep. 23, 1986
`
`Sheet4of8
`
`4,613,901
`
`:04
`
`A
`
`‘
`
`°
`
`A/D
`
`'23
`
`I06
`
`I07
`
`.05
`
`B _
`
`46b
`
`A/D
`
`:5
`
`124
`
`I5
`
`:25
`
`II
`
`I26
`
`MUX
`
`compaessmm
`
`‘
`
`I08
`
`:35
`
`IH
`
`.09
`
`
`N
`:32 . PARITY BIT
`'
`'35“
`"0
`
`
`.00
`H
`'34
`GENERATOR ’
`
`I2
`
`I
`
`55¢
`
`
`
`KEYSTREAM
`
`
`
`
`
`B
`INTERLEAVER
`
` H9 I43 2
`
`FIFO
`QUEUE
`
`2
`
`I44
`X
`
`M”
`
`2
`
`I20
`SHIFT
`REGISTER
`
`2
`
`|2|
`8
`PAM DATA
`CONVERTER .95
`
`SYNC
`
`I02
`
`CONTROL DATA
`
`IOI
`
`‘ffiki
`
`4?
`
`» PMC Exhibit 213
`
`Apple v. PM
`|PR2016-0075
`
`Page
`
`H3
`
`A
`INTERLEAVER
`
`
`
`
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 5
`
`

`
`3D...3U
`
`tn
`
`eS
`
`3920..
`
`.91
`
`600
`
`56.
`
`4
`
`31
`
`0
`
`r09..
`
`om.omo_>omjms_<mommo
`
`
`
`
`
`
`
`0/9.5.o_o:<om._m2<mowmo
`
`1,WI
`
`mmmM.Mv.nuPmmmxP0E0.2CAW
`
`532<momn._o
`
`Ex
`
`
`
`1mEmznzzofiqmmzmoExEmiommsmS2m_»m»m
`
`
`
`ZO:.Dm_m._.m_Omm.Ex>mO0m._.<UouE>muzm
`
`mm.O2<.u_Em>mv_
`
`
`
`.6528mmmoomm
`
`..<zo.m
`
`mommmoomm
`
`
`
`mmmEoo<Eoemfio
`
`$._m2<mumwo
`
`
`
`weExdzz<:o8E>mozm
`
`m 9
`
`F2300mz<E>H
`
`
`
`Em..0\k>»om_._m_s_<mom
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 6
`
`
`
`
`
`
`

`
`U.S. Patent
`
`Sep. 23, 1986
`
`Sheet6of8
`
`4,613,901
`
`I78
`
`' 5
`
`6
`
`54 KEYSTREAM
`GENERATOR
`
`KEYSTREAM
`54
`I59
`
`
`
`.
`WORKING
`KEY
`GENERATOR
`
`.92
`
`I90
`
`I93
`
`’
`
`I77
`
`TRUNCATE
`
`
`
`WOEEKYING
`
`174
`I73
`'89
`’ TRUNCATE
`e4
`
`56
`
`.cHANNEL
`KEY
`
`137
`
`A
`
`I88
`
`24
`
`FRAME
`00 NT,53
`
`EXPAND
`
`54
`
`.9.
`
`ENCRYPTED
`CHQENYNEL
`I54
`64
`
`I7!
`CHANNEL
`KEY
`GENERATOR
`
`CATEGORY
`ADRESS
`I55
`
`I6
`
`'73
`EXPAND
`
`’
`
`64
`
`-ENCRYPTED
`
`C‘}(TE§,G0RY
`'56
`64
`
`1361.3
`
`I67
`
`A
`
`'69
`CATEGORY
`GENERATOR
`M 1 64
`KEY
`. '85
`
`
`56
`
`SUBSCRIBER KEY
`
`
`
`
`I82
`
`'
`
`I64
`
`SUBSCRIBER
`
`158
`
`A
`use
`
`'70
`TRUNCATE
`
`CATEGORY
`56
`
`KEY
`
`6
`
`|6
`
`TRuNcATE
`
`
`
`SUBSCRIBER KEY
`GENERATION NUMBER
`I57
`32
`
`
`'65
`SUBEE$lBER
`GENERATOR _
`
`
`
`I8!
`
`
`
`2
`
`.
`
`56 I63
`'79
`SUBSCRIBER
`KEY
`
`SUBSCRIBER KEY
`SEED SELECTION
`
`55593
`
`_
`
`F/Q 5
`
`PMC Exhibit 213
`
`Apple v. PM
`|PR2016-0075
`
`Page
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 7
`
`

`
`U.S. Patent
`
`Sep. 23,1986
`
`Sheet7of8
`
`4,613,901
`
`¢.m_>wv_:_wZZ<IUQm._.n_>m_UZmu_OK._.ZOU
`
`Exam
`
`
`
`ma<3$._._oEzoo
`
`ma
`
`mobzmzuo
`
`mum
`
`uz>mxaz
`
`mmopmmm
`
`mm.228m2<EZmmmEm
`
`
`
`8._ms_<mo$omsmsoour.
`
`
`
`om.Etnauz_._
`
`mmmpznoo
`
`mmumoo<
`
`mmumoo<
`
`ZQFUMFND.I92
`
`mma2<4o
`
`¢a
`
`mom
`
`
`._mmmz:omo_>ommomoom
`nmmwawmza2mamw_n__.Es_<>»
`
`.oz<mm.
`mmmuammomjmzéom
`
`
`
`
`992
`
`
`
`
`om.>mx>moou»<oom»¢>mozunvm
`mm.mmmE8<Eoomfioomommmoomammmmooma
`
`
`
`
`
`
`
`
`
`Nn_mmmzpzzo:<mmzuo>mxmuemommpm
`
`
`
`mm.2<um»m»wx
`
`
`
`
`
`mm.Jomhzoommmooma
`
`.9
`
`ougmzqmommo
`
`9034K.®P.\
`
`PMC Exhibit 213
`
`Apple v. PM
`|PR2016-0075
`
`Page
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 8
`
`
`
`
`
`
`
`

`
`U.S. Patent
`
`Sep.23, 1986
`
`Sheet8of8
`
`4,613,901’
`
`227
`
`250 8
`
`25I
`PAM DATA
`
`2
`
`252
`FIFO
`
`I5
`
`SYNC AND TIMING
`
`243
`
`27|
`
`A
`DEINTERLEAVER
`
` 253
`
`B
`DEINTERLEAVER Z74
`
`
`
`
`255
`
`A
`REGISTER
`
`REGISTER
`
`HAM MING
`CODE ERROR
`
`
`
`CORRECTOR
`
` I29
`
`266
`D/A
`
`267
`
`[)/A
`
`-'5'“
`
`I6|b
`
`PMC Exhibit 213
`
`Apple v. PM
`|PR2016-0075
`
`Page
`
`EXPANSION
`
`'5
`
`265
`DEMUX
`
`292
`
`_
`
`FIG. 8
`
` 2
`
`242
`
`258
`KEYSTREAM '3
`REGISTER
`
`278
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 9
`
`

`
`1
`
`4,613,901
`
`SIGNAL ENCRYPTION AND DISTRIBUTION
`SYSTEM FOR CONTROLLING SCRAMBLING
`AND SELECTIVE REMOTE DESCRAMBLING OF
`TELEVISION SIGNALS
`
`BACKGROUND OF THE INVENTION
`
`The present invention generally pertains to subscrip-
`tion television systems and is particularly directed to a
`system for controlling scrambling and selective, remote
`descrambling of television signals.
`There are many schemes for controlling scrambling
`and selective, remote descrambling of television signals
`available for use in subscription television systems, in-
`cluding schemes wherein only selected subscribers’
`descramblers are addressed to be enabled to descramble
`scrambled television signals. These schemes heretofore
`have not provided the degree of security against unau-
`thorized descrambling that is desired by the subscrip-
`tion television industry.
`
`SUMMARY OF THE INVENTION
`
`The present invention is characterized by a key signal
`encryption and distribution system for scrambling and
`selective, remote descrambling of television signals.
`The present
`invention utilizes advanced crypto-
`graphic techniques to provide a video scrambling and
`selective descrambling system that is highly secure
`against unauthorized descrambling.
`Such security is based in part upon the use of an
`encryption algorithm, such as the DES (Data Encryp-
`tion Standard) algorithm. The DES algorithm is keyed
`by a 56-bit key signal. Without knowing the content of
`the key signal, a DES encrypted message cannot be
`decrypted unless all 72,057,590,000,000,000 possible key
`signals are tested by trial and error. Such a task would
`require an incredibly expensive and powerful computer.
`Since there is no such thing as an “unbreakable” deter-
`ministic cipher generator, the best one can hope for is to
`make the cryptanalysis process vastly more expensive
`than the value of the information that one is trying to
`protect. The DES algorithm succeeds in this endeavor
`quite nicely for subscription TV systems. The DES
`algorithm is the one commercially available crypto-
`graphic algorithm that has been most thoroughly ana-
`lyzed and tested under attack and which is now be-
`lieved to provide an extremely high level of security. At
`least three levels of encryption algorithms are used in
`scrambling and descrambling the television signal in the
`system of the present invention.
`The following functions are performed in the system
`of the present invention.
`A subsystem in each descrambler provides a sub-
`scriber key signal that is unique to the descrambler.
`A control computer stores a list of the unique sub-
`scriber key signals for the descramblers of the system.
`The control computer also stores a list defining a hierar-
`chy of common category key signals corresponding to a
`hierarchy of address groups defined on the basis of
`subscribers having a common grade of service or other
`attributes that makes it desirable to address a group of
`subscribers’ descramblers in common.
`The control computer generates from the stored hier-
`archy list, a common category key signal corresponding
`to a selected address group in the hierarchy of address
`groups. The computer further generates from the stored
`subscriber key signal list, a group of unique subscriber
`
`5
`
`I0
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`2
`key signals corresponding to the selected address
`group.
`The scrambler generates a group of unique encrypted
`category key signals individually addressed to different
`selected subscribers’ descramblers by processing the
`generated common category key signal in accordance
`with a first encryption algorithm upon the first algo-
`rithm being keyed by the generated group of unique
`subscriber key signals; generates a working key signal
`by processing an initialization vector signal in accor-
`dance with a second encryption algorithm upon the
`second algorithm being keyed by either the generated
`common category key signal or some other key signal;
`generates a unique keystream by processing the initial-
`ization vector signal in accordance with a third encryp-
`tion algorithm upon the third algorithm being keyed by
`the working key signal; and scrambles a television sig-
`nal in accordance with the unique keystream to provide
`a scrambled television signal.
`Preferably, a new working key signal is generated
`every few TV frames. The initialization vector signal is
`a signal derived from real time that is communicated to
`the descrambler as a synchronization control signal.
`Preferably it provides a time-based repetitive sequen-
`tially varying count of TV frames.
`The category membership of a subscriber defines the
`grade of service that a subscriber receives. Preferably
`the category key signal is varied from time to time, such
`as weekly, or whenever the subscriber’s grade of ser-
`vice is changed.
`Preferably the control computer stores a list defining
`a plurality of charmel key signals respectively corre-
`sponding to different time blocks for different television
`charmels in the system, and generates a selected channel
`key signal from said channel key signal list; and the
`scrambler generates an encrypted channel key signal by
`processing the selected channel key signal in accor-
`dance with a fourth encryption algorithm upon the
`fourth algorithm being keyed by the generated common
`category key signal; and generates the working key
`signal by processing the initialization vector signal in
`accordance with the second encryption algorithm upon
`the second algorithm being keyed by the selected chan-
`nel key signal.
`the initialization
`The scrambled television signal,
`vector signal, and the group of unique encrypted cate-
`gory key signals are communicated to the subscribers’
`descramblers.
`Each descrambler reproduces the common category
`key signal, when the descrambler receives the unique
`encrypted category key signal addressed thereto, by
`processing the encrypted category key signal addressed
`to the descrambler in accordance with the first algo-
`rithm upon the first algorithm being keyed by the
`unique subscriber key signal provided in the addressed
`descrambler; reproduces the working key signal, when
`the common category key signal is reproduced in the
`descrambler, by processing the initialization vector
`signal in accordance with the second algorithm upon
`the second algorithm being keyed by either the com-
`mon category key signal that is reproduced in the de-
`scrambler in relation to the reproduced common cate-
`gory key signal (such as the selected charmel key sig-
`nal), consistent with which key signal was used to key
`the second algorithm in the scrambler; reproduces the
`unique keystream, when the working key signal is re-
`produced in the descrambler, by processing the initial-
`ization vector signal in accordance with the third algo-
`
`PMC Exhibit 213
`
`Apple v. PM
`|PR2016-0075
`
`Page 1
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 10
`
`

`
`3
`rithm upon the third algorithm being keyed by the
`working key signal that is reproduced in the descram-
`bler; and descrambles the scrambled television signal,
`when the unique keystream is reproduced in the de-
`scrambler, by descrambling the scrambled television
`signal in accordance with the unique keystream that is
`reproduced in the descrambler.
`A given descrambler cannot decrypt an encrypted
`category signal unless the unique subscriber key signal
`for the given descrambler was used to encrypt the com-
`mon category signal.
`Each descrambler includes a secure memory for stor-
`ing information that is used for providing the unique
`subscriber key signal in the descrambler. The secure
`memory makes the system of the present invention
`additionally secure. Even if a cryptanalyst were
`equipped with an operable descrambler, a complete set
`of drawings, and advanced cryptographic equipment he
`would not be able to descramble the television signal
`unless the descrambler memory contained information
`essential to providing a key signal identical to one of the
`unique subscriber key signals used in encrypting the
`category key signal. Only unique subscriber key signals
`of authorized subscribers are used in encrypting the
`category key signal. The information for providing the
`unique subscriber key signal is stored in a secure inter-
`nal read only memory (ROM) of a microprocessor chip
`having internal architecture that prohibits the ROM
`from being read off-chip. Since the ROM can only be
`read by the microprocessor, a high level of security
`against disclosing the unit key signal to signal process-
`ing methods of analysis is assured.
`In the preferred embodiment, a subscriber key gener-
`ation number that is common to all of the subscribers’
`descramblers corresponding to selected address group
`is generated by the control computer and communi-
`cated to the subscribers’ descramblers together with the
`group of unique encrypted category key signals. In such
`embodiment the subscriber key subsystem in each de-
`scrambler combines the communicated subscriber key
`generation number with a unique subscriber address
`signal stored in the secure memory of the descrambler
`to provide a unique subscriber key generation signal.
`The subsystem provides the unique subscriber key sig-
`nal by processing the subscriber key generation signal in
`accordance with an encryption algorithm upon the
`algorithm being keyed by a subscriber key seed signal
`that is unique to the descrambler. The subscriber key
`seed signal preferably is stored in the secure memory of 50
`the descrambler and is retrieved therefrom to key the
`encryption algorithm in response to a predetermined
`seed address included in a given position in the sub-
`scriber key generation number.
`Although the present invention is described herein as
`being applicable to a subscription television system, it
`also is broadly applicable to other types of communica-
`tions systems.
`Additional features of the present invention are de-
`scribed in relation to the description of the preferred
`embodiment.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`Ass
`
`4,613,901
`
`4
`FIG. 3 is a block diagram of the scrambler signal
`processor included in the system of FIG. 1.
`FIG. 4 is a block diagram of the audio processor
`included in the scrambler signal processor of FIG. 3.
`FIG. 5 is a block diagram of a preferred embodiment
`of a descrambling system according to the present in-
`vention.
`FIG. 6 is a block diagram of the descrambler key
`distribution system included in the system of FIG. 5.
`FIG. 7 is a block diagram of the descrambler signal
`processor included in the system of FIG. 5.
`FIG. 8 is a block diagram of the audio processor
`included in the descrambler signal processor of FIG. 7.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Referring to FIG. 1, a preferred embodiment of a
`scrambling system according to the present invention
`includes a scrambler signal processor 10, a scrambler
`key distribution system 11 and a control computer 12.
`The control computer 10 stores a list of subscriber
`key signals that are unique to the different descramblers
`of the subscription television system.
`The control computer 12 also stores a list defining a
`hierarchy of address groups defined on the basis of
`subscribers having a common grade of service or other
`attributes that makes it desirable to address a group of
`subscribers’ descramblers in common. From the stored
`hierarchy list, the control computer 12 generates a 56-
`bit common category key signal on line 13 correspond-
`ing to a selected address group in the hierarchy of ad-
`dress groups.
`From the stored subscriber key signal list, the control
`computer 12 generates a group of unique 56-bit sub-
`scriber key signals on line 14 corresponding to the se-
`lected address group.
`The control computer 12 further stores a list defining
`a plurality of channel key signals respectively corre-
`sponding to different time blocks for different television
`channels, and generates a selected 56-bit channel key
`signal from the channel key signal list onto line 15.
`Together with the channel key signal on line 15, the
`control computer 12 generates a selected 16-bit cate-
`gory address signal on line 16 corresponding to the
`selected address group.
`The control computer 12 generates a 32-bit sub-
`scriber key generation number on line 17 that is com-
`mon to all of the subscribers’ descramblers.
`'The control computer additionally stores a list of
`32-bit subscriber address signals that are unique to the
`different descramblers of the subscription television
`system, and generates a group of unique 32-bit sub-
`scriber address signals corresponding to the selected
`address group from the unit address signal
`list. The
`unique subscriber address signals on line 18 are gener-
`ated on line 18 by the control computer 12 together
`with the respective unique subscriber key signals gener-
`ated by the control computer on line 14.
`In addition, the control computer 12 generates a 24-
`bit initialization vector (IV) frame count signal on line
`19 and process control signals on lines 20. The IV signal
`on line 19 is a time-based signal indicating a repetitive
`sequentially varying count. In an alternative preferred
`embodiment (not shown) the IV frame count signal is
`produced in the scrambler signal processor 10 and pro-
`vided therefrom to the scrambler key distribution sys-
`tem 11.
`
`PMC Exhibit 213
`
`Apple v. PM
`|PR2016-0075
`
`Page 11
`
`BRIEF DESCRIPTION OF THE DRAWING
`
`FIG. 1 is a block diagram of a scrambling system
`according to the present invention.
`FIG. 2 is a block diagram of a preferred embodiment
`of the scrambler key distribution system included in the
`system of FIG. 1.
`
`65
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 11
`
`

`
`4,613,901
`
`6
`The keystream generator 21 generates a unique 64-bit
`keystream by processing the initialization vector signal
`on line 30 in accordance with the DES encryption algo-
`rithm upon the DES algorithm being keyed by the
`working key signal on line 43. The unique keystream is
`provided on line 44 to the scrambler signal processor
`10.
`
`5
`The process control signals on lines 20 effect control
`of various processes in the scrambler signal processor
`10 and the descrambling system of FIG. 5.
`Referring to FIG. 2, the scrambler key distribution
`system 11 includes a keystream generator 21, a working
`key signal generator 22, an encrypted channel key sig-
`nal generator 23 and an encrypted category key signal
`generator 24. The scrambler key distribution system of
`FIG. 2 further includes five expansion function ele-
`ments 25, 26, 27, 28 and 29 for expanding the signals
`respectively received from the control computer 12 on
`lines 19, 15, 16, 13 and 18 to 64 bits. Expansion is accom-
`plished by adding various sets of predetermined bit
`combinations to the end of each of the respectively
`received signals so that the word lengths match. Such
`expansion is implemented by programmed operation of
`a microprocessor. Accordingly a 24-bit initialization
`vector signal on line 19 is expanded to a 64-bit signal on
`line 30; the 56-bit channel key signal on line 15 is ex-
`panded to a 64-bit signal on line 31; the 16-bit category
`address signal on line 16 is expanded to a 64-bit signal on
`line 32; the 56-bit category key signal on line 13 is ex-
`panded to a 64-bit signal on line 33; and the 32-bit sub-
`scriber address signal on line 18 is expanded to a 64-bit
`signal on line 34.
`In addition, the scrambler key distribution system of
`FIG. 2 includes two exclusive-OR logic elements 35
`and 36. The logic element 35 exclusive-OR’s the se-
`lected charmel key signal on line 31 with the category
`address signal on line 32 to provide a scrambled selected
`channel key signal on line 37. The logic element 36
`exclusive-OR’s the common category key signal on line
`33 with the subscriber address signal on line 34 to pro-
`vide a scrambled common category key signal on line
`38.
`
`The encrypted category key signal generator 24 gen-
`erates a group of unique 64-bit encrypted category key
`signals individually addressed to different selected sub-
`scribers’ descramblers by processing the scrambled
`common category key signal on line 38 in accordance
`with the DES encryption algorithm upon the DES
`algorithm being keyed by the group of unique sub-
`scriber key signals received on line 14 from the control
`computer 12. The group of encrypted category key
`signals are provided sequentially on line 39 to the
`scrambler signal processor 10 (FIGS. 1 and 3).
`The encrypted charmel key signal generator 23 gen-
`erates a 64-bit encrypted channel key signal by process-
`ing the scrambled selected channel key signal on line 37
`in accordance with the DES encryption algorithm upon
`the DES algorithm being keyed by the generated com-
`mon category key signal received on line 13 from the
`control computer 12. The encrypted channel key signal
`is provided on line 40 to the scrambler signal processor
`10.
`The working key signal generator 22 generates a
`64-bit working key signal by processing the initializa-
`tion vector signal on line 30 in accordance with the
`DES encryption algorithm upon the DES algorithm
`being keyed by the generated channel key signal on line
`15. The generated working key signal is provided on
`line 41 and truncated by a truncation function element
`42 to a 56-bit signal on line 43. Truncation is accom-
`plished by deleting the last eight bits from the 64-bit
`signal. In the preferred embodiment, a new working
`key is generated every four TV frames or at a 7.5 Hz
`rate.
`
`10
`
`I5
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`65
`
`Referring to FIG. 1, the scrambler signal processor
`10 scrambles a video signal received on line 45 and an
`audio signal received on line 46 in accordance with the
`unique keystream received on line 44 to provide a
`scrambled television signal on line 47.
`Referring to FIG. 3, the scrambler signal processor
`10 includes a control processor 48, an audio processor
`49, a video amplifier 50, a sync detection circuit 51, an
`analog-to-digital (A/D) converter 52, a video line
`buffer memory 53, address counters 54, an address
`FIFO (first-in/first-out) queue 55, a line buffer control-
`ler 56, a waveshaping filter 57, a burst generator 58, a
`sync generator 59, a reference pattern generator 60, a
`multiplexer (MUX) 61 and a digital-to-analog (D/A)
`converter 62. The operation of the control processor 48
`is controlled by process control signals provided on line
`20 by the control computer 12.
`The video signal on line 45 is scrambled in accor-
`dance with one portion of each frame of the unique
`keystream on line 44. The audio signal on line 46 is
`scrambled by the audio processor 49 in accordance with
`a different portion of each frame of the unique keys-
`tream from line 44 that is provided to the audio proces-
`sor on line 63.
`The video amplifier 50 amplifies the video signal on
`line 45 and filters the same to remove any extraneous or
`harmonic signals. The amplified and filtered video sig-
`nal is provided on line 63 to the A/D converter 52 and
`the sync detection circuit 51. The sync detection circuit
`51 detects the vertical and horizontal synchronization
`signals in the video signal on line 63 and responds
`thereto by providing synchronization control and
`clocking signals on lines 64 to the control processor 48.
`Among these clocking signals is a 14.32 MHz signal,
`which is at four times the color subcarrier frequency of
`an NTSC video signal, and which is also provided by
`the sync detection circuit 51 on line 64a to clock the
`A/D converter 52.
`The A/D converter 52 converts the amplified video
`signal on line 63 into a digital video information signal
`on line 65 at the sampling rate of 14.32 MHz to provide
`910 8-bit samples per video line. The active video infor-
`mation corresponds to 744 samples in each line.
`The video line buffer memory 53 stores the digital
`video signal on line 65 in four groups of four video
`information lines each. Each stored video information
`line includes 744 8-bit samples of active video informa-
`tion. A first group includes four consecutive odd-num-
`bered lines from the same video field. A second group
`includes the next four consecutive odd numbered lines
`from the same video field. A third group includes four
`consecutive even-numbered lines from the same video
`field, and the fourth group includes the next four con-
`secutive even-numbered lines from the same video field.
`One group of odd-numbered lines is stored in the mem-
`ory 53 while the information from the previously-stored
`group of odd-numbered lines is retrieved from the mem-
`ory 53 to form a four-line group of odd-numbered
`scrambled video information line on line 66. Likewise,
`one group of even-numbered lines is stored in the mem-
`ory 53 while the information from the previously stored
`
`PMC Exhibit 213
`Apple v. PM
`IPR2016-0075
`
`Page 1
`
`PMC Exhibit 2132
`Apple v. PMC
`IPR2016-00753
`Page 12
`
`

`
`4,613,901
`
`10
`
`15
`
`25
`
`30
`
`35
`
`40
`
`7
`group of even-numbered lines is retrieved from the
`memory to form a four-line group of even-numbered
`scrambled video information lines on line 66. Video
`scrambling is accomplished by retrieving the active
`video information from the memory in a sequence dif-
`ferent from that in which it was stored.
`The address counters 54 provide the respective ad-
`dresses on line 67 to the memory 53 for storing and
`retrieving video information. These addresses are pro-
`vided to the address counters 54 on line 68 via the ad-
`dress FIFO queue 55 and line 69 from the control pro-
`cessor 48 in accordance with the unique keystream
`provided to the control processor 48 on line 44.
`The line buffer controller 56 provides clocking and
`control signals on lines 70 for synchronizing the opera-
`tions of the address FIFO queue 55, the address count-
`ers 54 and the memory 53 in accordance with clocking
`and synchronization control signals provided on line 71
`by the control processor 48. The control processor 48
`provides the clocking and synchronization control sig-
`nals on lines 71 in response to the clocking and synchro-
`nization control signals received on lines 64 from the
`sync detection circuit 51.
`Scrambling is accomplished within four-line groups.
`Two control bits of the keystream on line 44 designate
`which lines within a given, stored four-line group are to
`be paired for forming a corresponding pair of scrambled
`video information lines. The relative lengths of the
`retrieved portions in each pair of scrambled lines is
`designated by six control bits in the keystream, which
`indicate a cutpoint as being after a given number of
`segments from the beginning of the line.
`Another five control bits of the keystream on line 44
`designate the sequence within a four-line group in
`which the scrambled lines are formed. Twenty-four
`different sequences are possible. Thus nineteen bits of
`the keystream are used every four video line times to
`select one of 3X62X24=276,768 possible scrambling
`patterns. Descrambling requires local generation of the
`identical keystream in the descrambler.
`To further obscure the location of the cutpoint, the
`waveshaping filter 57 adjusts the values of the adjacent
`extremities of the retrieved portions of each scrambled
`line to smooth over any fast rise-time edges.
`The waveshaping filter 57 provides a smooth transi-
`tion between two nine-bit samples in a digital data
`stream separated by six clock periods. The process in-
`volves generating a plurality of interpolated values
`between the two selected samples in different adjacent
`retrieved portions of each scrambled line and inserting
`samples ha