[ 0029 ] fig1 illustrates one embodiment of a content transmission system 100 . the content transmission system 100 comprises a plurality of global positioning system ( gps ) satellites 102 , an advanced television systems committee ( atsc ) transmitter 104 , an atsc communication path 110 , one or more terrestrial integrated receivers / descramblers ( irds ) 116 , a direct broadcast satellite ( dsb ) dish 106 , a dbs communication path 112 , one or more consumer irds 118 , a quadrature amplitude modulation ( qam ) modulator 108 , a cable 114 and one or more digital set - top boxes ( stbs ) 120 . the atsc transmitter 104 in fig1 transmits content signals , such as advanced tv ( atv ), digital tv ( dtv ) or high definition tv ( hdtv ) signals , via the atsc path 110 to one or more terrestrial irds 116 . the dbs dish 106 transmits content signals via the dbs path 112 to one or more consumer irds 118 . the qam modulator 108 transmits content signals via the cable 114 to one or more digital set - top boxes 120 . the system 100 in fig1 may have any number of atsc transmitters 104 , dbs dishes 106 , qam modulators 108 , terrestrial irds 116 , consumer irds 118 and digital set - top boxes 120 . the irds 116 , 118 and stbs 120 in fig1 are configured to receive and decode encrypted or scrambled signals transmitted by the atsc transmitter 104 , the dbs dish 106 and the qam modulator 108 , respectively . the irds 116 , 118 and the stbs 120 may be referred to herein as ‘ content receivers ,’ ‘ content players ,’ or ‘ content processing devices .’ the content receivers / players 116 - 120 in fig1 may be used in any suitable location , such as a residence , a vehicle or a business , such as a movie theater , a bar or a restaurant . the content receivers / players 116 - 120 in fig1 each contain a gps receiver , as described below , which may be used to authenticate the locations of the content receivers / players 116 - 120 . [ 0032 ] fig2 illustrates one embodiment of a content processing device 200 in the system 100 of fig1 . the content processing device 200 may comprise a content receiver , such as a set - top box , a content player , such as a dvd player , or both . thus , the content processing device 200 may be referred to herein as a ‘ content receiver ,’ a ‘ content player ’ or both . the content receiver / player 200 of fig2 may represent the terrestrial ird 116 , the consumer ird 118 , the digital set - top box 120 or a combination of the irds 116 , 118 and the set - top box 120 in fig1 . the content processing device 200 in fig2 may interface with a conditional access ( ca ) module 236 , a minidisc player 240 , a digital vhs ( d - vhs ) player 242 , an audio / video ( a / v ) hard disk player 244 , a home control unit 246 , a first display 248 , external media reader 250 b and / or a second display 228 . in one embodiment , the ca module 236 is integrated with the content receiver / player 200 . the content receiver / player 200 in fig2 comprises an antenna or port 201 , such as a coaxial cable , a data over cable systems interface specifications ( docsis ) or cablelabs certified cable modem 202 , a qam / vestigial sideband ( vsb )/ quatemary phase shift keying ( qpsk ) tuner 204 , a qpsk transmitter and receiver out - of - band ( oob ) unit 206 , a demodulator 208 , a central processing unit ( cpu ) 210 ( also called a ‘ host cpu 210 ’ or ‘ main cpu 210 ’), a gps receiver 212 , a cp de - scrambling unit 216 , a demultiplexer ( demux ) 214 , a telephone port 218 , a moving pictures experts group ( mpeg ) decoder 220 , an ieee 1394 bus interface 222 , a graphics unit 224 , a digital video interface ( dvi ) unit 226 , a media reader 250 a and an access criteria receiver 252 . in one embodiment , the cryptographic cpu 230 in fig2 is housed in an integrated circuit ( ic ), such as a smart card ic . in one embodiment , the gps receiver 212 is part of a gps module that is separate from the content receiver / player 200 in fig2 . the main cpu 210 interacts with the gps unit , whether a module or embedded in the player / receiver , and passes the gps location information to the cryptographic cpu 230 . other embodiments of the content receiver / player 200 may not comprise all of the components listed above . for example , one embodiment of the content receiver / player 200 in fig2 comprises either a docsis modem 202 , a qam / vsb / qpsk tuner 204 or a qpsk transmitter and receiver oob unit 206 , but not all three components . as another example , one embodiment of the content receiver / player 200 communicates with an external media reader 250 b and does not have an internal media reader 250 a . as another example , one embodiment of the content receiver / player 200 receives access criteria with the content signals and does not have an access criteria receiver 252 . other embodiments of the content receiver / player 200 may comprise additional components instead of or in addition to the components listed above . in fig2 the docsis modem 202 , qam / vsb / qpsk tuner 204 and qpsk transmitter and receiver oob unit 206 are configured to receive various content signals ( e . g ., cable , terrestrial , dbs ) via antenna / port 201 transmitted by one or more content providers with the atsc transmitter 104 , the dbs dish 106 and the qam modulator 108 of fig1 . the content providers , such as a cable tv operator , typically modulate the content signals for transmission . for example , the signals may be formatted according to 8 - vsb , which is a standard radio frequency ( rf ) modulation format used by atsc for transmitting digital tv ( dtv ) signals . the content providers may also scramble / encrypt the content signals in an attempt to prevent unauthorized reception . the demodulator 208 in fig1 demodulates the content signals received by the docsis modem 202 , qam / vsb / qpsk tuner 204 and / or qpsk transmitter and receiver oob unit 206 . the demodulator 208 transfers the demodulated content signals to the descrambler 234 in the ca module 236 . in addition to or instead of the signals from the demodulator 208 , the media reader 250 a or 250 b in fig2 may transfer scrambled content signals to the descrambler 234 in the ca module 236 . the media readers 250 a and 250 b are configured to read scrambled content from a media , such as a cassette tape , cd , floppy disk or dvd and transfer the read content to the descrambler 234 . the ca module 236 in fig2 may comprise a point of deployment ( pod ) conditional access module , a national renewable security system part b ( nrss - b ), a digital video broadcasting ( dvb ) common interface module ( e . g ., used in europe ) or a portable module such as a personal computer memory card international association ( pcmcia ) type 2 form factor . the ca module 236 comprises a cpu 230 , a copy protection ( cp ) scrambling unit 232 , a descrambler 234 and an access criteria receiver 254 . other embodiments of the ca module 236 may not comprise all of the components shown in fig2 . for example , one embodiment of the ca module 236 does not have an access criteria receiver 254 . other embodiments of the ca module 236 may comprise other components , such as a gps receiver 260 , in addition to or instead of the components shown in fig2 . thus , in one embodiment , the gps receiver 260 is physically located in the ca module 236 instead of a gpd receiver 212 in the player / receiver 201 . in another embodiment , the gps receiver 212 is closely coupled with the ca module 236 . in one embodiment , a content provider creates access criteria and transmits the access criteria in - band with content signals to the content receiver / player 200 , as described below with reference to fig3 . for example , the access criteria may be ‘ meta - data .’ in one embodiment , the demodulator 208 in fig2 transfers the content signals and the access criteria to the cpu 210 , which transfers the content signals and the access criteria to the cryptographic cpu 230 . in another embodiment , the demodulator 208 transfers the access criteria and / or any entitlements associated with the content directly to the ca module 236 . the cryptographic cpu 230 processes access criteria in the content signals . in one embodiment , the cpu 230 stores the access criteria . in one embodiment , the cpu 230 derives any content keys , i . e ., entitlement control messages ( ecm ), from the access criteria . in this embodiment , the cpu 230 sends the keys to the descrambler 234 to descramble the content . in another embodiment , a content provider transmits the access criteria independently of the content signals to the receiver 254 in fig2 which transfers the access criteria to the cpu 230 . the cpu 230 processes the access criteria . in another embodiment , a content provider transmits access criteria to the receiver 252 in fig2 which transfers the access criteria to the cpu 230 . the access criteria may comprise ‘ positive ,’ ‘ negative ’ or ‘ positive and negative ’ access criteria . ‘ positive ’ access criteria specify one or more locations or regions where one or more content receivers / players 200 are authorized to descramble content , such as a video - on - demand ( vod ) program . in one embodiment , the content is intended for a particular content receiver / player 200 in a particular location or region . ‘ negative ’ access criteria specify one or more locations or regions where one or more content receivers / players 200 are not authorized to descramble content . if a receiver / player 200 is not in one or more pre - determined specified locations or regions , then the receiver / player 200 may descramble the received content . ‘ positive and negative ’ access criteria specify at least one location where at least one content receiver 200 is authorized to descramble content signals and at least one location where at least one content receiver 200 is not authorized to descramble content signals the access criteria may comprise a relatively long list of authorized and / or unauthorized locations or regions . the access criteria may also comprise a time period when a content receiver 200 is authorized or not authorized to descramble content signals . in another embodiment , a content provider sends the access criteria to the content receiver / player 200 and / or the ca module 236 independently of the content signals . in another embodiment , the access criteria are pre - stored in the content receiver / player 200 when the content receiver / player is manufactured . the cpu 230 in fig2 may also process entitlement information and enforce the business rules of a service provider , such as a cable operator with monthly subscriptions . for example , the cpu 230 will grant a content receiver / player 200 access to content signals after the cpu 230 receives authorization from the cable operator that the customer has paid a monthly bill . the gps receiver 212 in fig2 receives a gps signal from a plurality of gps satellites 102 ( fig1 ) and determines the location of the content receiver / player 200 . the gps receiver 212 sends the location data to the cpu 210 automatically or upon a request from the cpu 210 . in one embodiment , the gps receiver 212 receives a gps signal within a particular time window , estimates a time when the signal was received and sends the estimated time with the location data to the cpu 210 , which sends the estimated time with the location data to the cryptographic cpu 230 . for example , the content receiver / player 200 may change locations from time to time or certain programming may be authorized from time to time . the gps receiver 212 is not required to send both location and time data to the cpu 210 , but location data used in conjunction with time data may improve the security of the content receiver / player 200 . if the ca module 236 has its own gps receiver 260 , the functions of the gps receiver 260 are substantially similar to the gps receiver 212 , except the gps receiver 260 sends an estimated time with location data directly to the cpu 230 . in one embodiment , the gps receiver 212 or 260 has its own security perimeter . the gps receiver 212 or 260 sends a cryptographic signature with the location and / or time data to the cryptographic cpu 230 to prevent a user from sending fake location and / or time data to the cpu 230 . the signature comprises a secret or private key , such as a predetermined sequence of bits . in this embodiment , the cpu 230 has a corresponding secret or private key . if the signature from the gps receiver 212 or 260 matches the key in the cpu 230 , then the cpu 230 uses the location and / or time data to determine whether or not the received content signals should be descrambled . the gps receiver 212 or 260 is not required to send a cryptographic signature with the location and / or time data to the cpu 230 , but the signature may improve the security of the content receiver / player 200 . in one embodiment , the cryptographic cpu 230 securely communicates using secret or public key cryptography to send a query and a nonce to the gps receiver 212 or 260 . a nonce is a ‘ challenge ’ or a random value generated fresh for each use and included in inter - processor exchanges to make each exchange unique . the gps receiver 212 or 260 returns a response along with the location information securely to the cryptographic cpu 230 . the response could be the original nonce value encrypted with the private key of the gps receiver 212 or 260 ( along with the location data ). alternatively , the response could be the nonce value hashed with the location data and then the hash encrypted with a shared secret key . the cryptographic processor 230 will examine the response from the gps receiver 212 or 260 to see if the response is truly from the gps receiver 212 or 260 . gps simulators currently exist to test devices with gps functions . for example , a gps simulator may be coupled to the gps receiver 212 or 260 in fig2 . the gps simulator may be configured to simulate signals from satellites corresponding to any location in the world . gps simulators are not commonly available , but they may be used to defeat the security of a gps - based content receiver / player 200 system as outlined herein . gps simulators generally provide highly accurate location signals , but do not provide a simulated , current time signal with the location signal . in one embodiment , the gps receiver 212 or 260 in fig2 is configured to output a time signal that is associated with each derived location signal . the cpu 230 compares an independent , secure time source , preferably a local time source , with a time presumably output by the gps receiver 212 or 260 to verify the authenticity of the location signal from the gps receiver 212 or 260 . if the time presumably output by the gps receiver 212 or 260 is within a predetermined range of the independent time source , then the cpu 230 uses the gps location signal from the gps receiver 212 or 260 . if the time presumably output by the gps receiver 212 or 260 is outside of a predetermined range of the independent time source , then the cpu 230 discards the gps location signal from the gps receiver 212 or 260 . the cryptographic cpu 230 in fig2 is a secure processor that communicates with the cpu 210 and the gps receiver 212 or 260 . the cryptographic cpu 230 receives location information from the cpu 210 or the gps receiver 260 and determines whether the location of the content receiver / player 200 meets the access criteria ( either positive or negative ). as explained earlier , in one embodiment , the processor 230 uses a real - time clock ( either an internal or an external clock ) to authenticate the time of the location data from the gps receiver 212 or 260 . the cpu 230 informs the cpu 210 whether the content receiver / player 200 is authorized to access the received content signals . determining whether a content receiver / player 200 is authorized to receive and play content may be referred to as an ‘ authorization process .’ if access is granted , the cryptographic cpu 230 sends a decryption key ( control signal ) to the descrambler 234 . the descrambler 234 in fig2 is configured to descramble content signals from the demodulator 208 or the media reader 250 a or 250 b . the copy protection ( cp ) scrambling unit 232 in fig2 is configured to scramble content signals for copy protection to keep an eavesdropper from illegally copying the content descrambled by the descrambler 234 , i . e ., prevent a user from intercepting the content signals from the descrambler 234 to the content receiver / player 200 and making unauthorized copies of the content signals . the cp scrambling unit 232 sends copy protected content signals to the cp de - scrambling unit 216 in the content receiver 200 . the cp de - scrambling unit 216 in fig2 is configured to descramble the copy protection placed on the content signals by the cp scrambling unit 232 . the demultiplexer 214 in fig2 demultiplexes the signals and passes the signals to the mpeg decoder 220 and the 1394 bus interface 222 . the mpeg decoder 220 decompresses / decodes video signals and may access the graphics unit 224 . the digital video interface ( dvi ) unit 226 delivers decompressed signals to one or more displays 228 . the ieee 1394 bus interface 222 is configured to send decompressed , decoded content signals to the minidisc player 240 , the d - vhs player 242 and / or the a / v hard disk player 244 . the minidisc player 240 , d - vhs player 242 , and a / v hard disk player 244 in fig2 are configured to store content received by the content receiver 200 and later retrieve the content for playback . in one embodiment , the minidisc player 240 , d - vhs player 242 , and a / v hard disk player 244 in fig2 are coupled together using an ieee 1394 network and comprise a home network system 238 . the displays 228 , 248 in fig2 are configured to display content , such as motion pictures , received by the content receiver 200 . the content signals output by content receiver / player 200 in fig2 may have an assigned state of copy protection , which may be set by the ca module 236 . for example , the content signals may have a ‘ copy never ’ state of copy protection , which prevents any form of copying . a ‘ copy free ’ state allows free copying . ‘ copy once ’ allows a onetime copy to be made . ‘ copy no more ’ prevents further copying . there may be other states for certain technologies , e . g ., for personal video recorders , one copy protection state may allow temporary storage , e . g ., less than 40 minutes . the home control unit 246 in fig2 is configured to control household devices , such as lights , heat , air conditioning , an alarm system and devices such as the content receiver 200 . in one embodiment , gps circuitry is embedded in or integrated with a cryptographic ic to perform the functions described above related to the content receiver 200 . for example , a gps chip , such as nav - 2100 or nav - 2300 , made by analog devices , inc . in norwood , mass ., may be modified to include or operate with a rf front end and a gps antenna . the nav - 2100 and nav - 2300 include a digital signal processor ( dsp ), an on - chip sram and a plurality of i / o peripherals . the nav - 2300 could be built into a cryptographic ic to perform the functions described above related to the content receiver 200 . in one embodiment , the content receiver / player 200 is configured to perform the functions of the ca module 236 described above , and a separate ca module 236 is not used . [ 0061 ] fig3 illustrates one embodiment of a content provider system 300 , which sends content signals to the content receiver / player 200 of fig2 . the content provider system 300 comprises a content source unit 302 , an access criteria unit 304 , a processor 306 and a transmitter 308 . the content source unit 302 comprises a storage device , such as one or more disk drives , disk arrays , computer servers or solid state memory , or a live content receiver , such as a camera at a sports event . those skilled in the art will understand the functions of the content source unit 302 , the processor 306 and the transmitter 308 , except for the functions described herein . the content source unit 302 in fig3 provides content signals to the processor 306 . the access criteria unit 304 in fig3 provides access criteria , such as a predetermined location and / or time data , to the processor 306 . the content provider , such as a cable or satellite company , may create and modify the access criteria . the processor 306 in fig3 associates the access criteria from the access criteria unit 304 with the content signals from the content source unit 302 and passes the access criteria and content signals to the transmitter 308 . the processor 306 , the content source unit 302 or the transmitter 308 may modulate the content signals for transmission and scramble / encode / encrypt the content signals to prevent unauthorized access to the content signals . the transmitter 308 in fig3 may represent the atsc transmitter 104 , dbs dish 106 or qam modulator 108 of fig1 . the transmitter 308 transmits the content signals and access criteria to at least one content receiver / player 200 in fig2 . as described above , in another embodiment , the processor 306 and the transmitter 308 send access criteria to content processing devices independently of the content signals . in another embodiment , the content provider system 300 in fig3 comprises a media writer 310 coupled to the processor 306 instead of or in addition to the transmitter 308 . the media writer 310 is configured to write scrambled content with access criteria from the processor 306 onto media , such as cassette tapes , compact discs ( cds ) and digital video discs ( dvds ). the media is sold in stores , rented , played by customers with content players or programmed in a device at a customer &# 39 ; s home after a download . the above - described embodiments of the present invention are merely meant to be illustrative and not limiting . various changes and modifications may be made without departing from the invention in its broader aspects . for example , in one embodiment , cellular phone signals are received by the ca module 236 and used to determine a location of a content processing device 200 instead of gps signals . the appended claims encompass such changes and modifications within the spirit and scope of the invention .