Patent JPS641918A successfully refreshed from Google Patents.
Patent US6516412B2 successfully refreshed from Google Patents.
US6516412B2
Expired / Lapsed
US
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Authorization of services in a conditional access system
Assignee: Tech 5 Sas
•
Filing: 2001-03-16
•
Granted: 2003-02-04
•
Expires: 2021-03-16
Abstract
Abstract A cable television system provides conditional access to services. The cable television system includes a headend from which service “instances”, or programs, are broadcast and a plurality of set top units for receiving the instances and selectively decrypting the instances for display to system subscribers. The service instances are encrypted using public and/or private keys provided by service providers or central authorization agents. Keys used by the set tops for selective decryption may also be public or private in nature, and such keys may be reassigned at different times to provide a cable television system in which piracy concerns are minimized.
Inventors
- 👤 Anthony J. Wasilewski
- 👤 Howard G. Pinder
- 👤 Glendon L. Akins, III
- 👤 Robert O. Banker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:50
CPC Classifications
H; H04; H04L; H04L63/00; H04L63/04; H04L63/0428; H04L63/0442; H04L63/045; H04L63/06; H04L63/062; H04L63/08; H04L63/0823; H04L63/12; H04L63/123; H04N; H04N21/00; H04N21/20; H04N21/21; H04N21/226; H04N21/2265; H04N21/23; H04N21/234; H04N21/2347; H04N21/23476; H04N21/25; H04N21/266; H04N21/26606; H04N21/40; H04N21/41; H04N21/426; H04N21/43; H04N21/44; H04N21/4405; H04N21/45; H04N21/4508; H04N21/4524; H04N21/60; H04N21/63; H04N21/633; H04N21/6332; H04N21/6334; H04N21/63345; H04N7/00; H04N7/16; H04N7/162; H04N7/163; H04N7/167; H04N7/1675; H04N7/173; H04N7/17345; H04N7/17354; H04J; H04J2203/00; H04J2203/0001; H04J2203/0073; H04J2203/008; H04L2463/00; H04L2463/101
Claims Analysis
Total Claims: 55
Claim 1
Independent Claim
291 words
A conditional access apparatus in the receiver for giving a receiver, in a cable television system, conditional access to a given encrypted instance of service of a plurality of encrypted instances of services received in the receiver, the conditional access apparatus comprising: an agent establishment apparatus adapted to establish an entitlement agent in the receiver in response to a first message received in the receiver, wherein the agent establishment apparatus imposes constraints in the receiver on the established entitlement agent, and the established entitlement agent is associated with the given encrypted instance of service, and wherein the agent establishment apparatus further disestablishes the established entitlement agent, whereupon the access granting apparatus no longer grants access to an instance of service associated with the disestablished entitlement agent; an entitlement specification apparatus in communication with the agent establishment apparatus, the entitlement specification apparatus adapted to specify the one or more service entitlements, wherein specified service entitlements include entitlements of the receiver for instances of services received in the receiver that are associated with the established entitlement agent; and an access granting apparatus in communication with the entitlement specification apparatus, the access granting apparatus adapted to grant access to the given instance of service in response to a second message received in the receiver, the second message includes an entitlement identifier associated with the given encrypted instance of service, wherein the access granting apparatus uses the specified service entitlement and the entitlement identifier to grant access to the given instance of service, and the access granting apparatus grants access to the given instance of service only if the agent establishment apparatus has established the entitlement agent, and the given instance of service includes services including programming that are provided to the cable television system.
Claim 2
Dependent Claim
291 words
A conditional access apparatus in the receiver for giving a receiver, in a cable television system, conditional access to a given encrypted instance of service of a plurality of encrypted instances of services received in the receiver, the conditional access apparatus comprising: an agent establishment apparatus adapted to establish an entitlement agent in the receiver in response to a first message received in the receiver, wherein the agent establishment apparatus imposes constraints in the receiver on the established entitlement agent, and the established entitlement agent is associated with the given encrypted instance of service, and wherein the agent establishment apparatus further disestablishes the established entitlement agent, whereupon the access granting apparatus no longer grants access to an instance of service associated with the disestablished entitlement agent; an entitlement specification apparatus in communication with the agent establishment apparatus, the entitlement specification apparatus adapted to specify the one or more service entitlements, wherein specified service entitlements include entitlements of the receiver for instances of services received in the receiver that are associated with the established entitlement agent; and an access granting apparatus in communication with the entitlement specification apparatus, the access granting apparatus adapted to grant access to the given instance of service in response to a second message received in the receiver, the second message includes an entitlement identifier associated with the given encrypted instance of service, wherein the access granting apparatus uses the specified service entitlement and the entitlement identifier to grant access to the given instance of service, and the access granting apparatus grants access to the given instance of service only if the agent establishment apparatus has established the entitlement agent, and the given instance of service includes services including programming that are provided to the cable television system.
Claim 3
Dependent Claim
29 words
The conditional access apparatus of claim 1 , wherein: the constraints imposed on the established entitlement agent includes a limit for the entitlements the established entitlement agent may offer.
Claim 4
Dependent Claim
22 words
The conditional access apparatus of claim 2 , wherein: the limit limits the kinds of entitlements the established entitlement agent may offer.
Claim 5
Dependent Claim
22 words
The conditional access apparatus of claim 2 , wherein: the limit limits the number of entitlements the established entitlement agent may offer.
Claim 6
Dependent Claim
29 words
The conditional access apparatus of claim 2 , wherein: the entitlement specification apparatus specifies the one or more service entitlements within the limit established by the agent establishment apparatus.
Claim 7
Dependent Claim
28 words
The conditional access apparatus of claim 1 , wherein: the agent establishment apparatus and the entitlement specification apparatus operate in response to further messages received in the receiver.
Claim 8
Dependent Claim
31 words
The conditional access apparatus of claim 6 , wherein: the agent establishment apparatus and the entitlement specification apparatus respond to the further messages without interruption to currently-granted access to the information.
Claim 9
Dependent Claim
54 words
The conditional access apparatus of claim 6 , wherein: the agent establishment apparatus and the entitlement specification apparatus include at least first and second keys, employ the at least first and second keys to determine whether a received message is authentic, and respond to the received message only if the received message is authentic.
Claim 10
Dependent Claim
56 words
The conditional access apparatus of claim 8 , wherein: the agent establishment apparatus, the entitlement specification apparatus, and the access granting apparatus are implemented in a secure element, which includes a processor and storage for the service entitlements and the keys, and the storage is writable and accessible only to the processor of the secure element.
Claim 11
Dependent Claim
31 words
The conditional apparatus of claim 8 , wherein: the further messages are encrypted; and the conditional access apparatus includes another key and employs the other key to decrypt the further messages.
Claim 12
Dependent Claim
36 words
The conditional access apparatus of claim 10 , wherein: the receiver has a public key and a private key; the further messages are encrypted with the public key; and the private key is the other key.
Claim 13
Dependent Claim
74 words
The conditional access apparatus of claim 8 , wherein: the second message includes an authentication token that was processed by the private key of a private key-public key associated with the entitlement agent; the access granting apparatus uses the authentication token with a public key of the established entitlement agent to determine whether the second message is authentic and grants access to the given instance of service only if the second message is authentic.
Claim 14
Dependent Claim
28 words
The conditional access apparatus of claim 6 , wherein: the agent establishment apparatus disestablishes the established entitlement agent in response to a third message of the further messages.
Claim 15
Dependent Claim
52 words
The conditional access apparatus of claim 13 , wherein: the agent establishment apparatus includes a first key representing a conditional access authority; and the agent establishment apparatus employs the first key to determine whether the third message is authentic and disestablishes the established entitlement agent only if the third message is authentic.
Claim 16
Dependent Claim
28 words
The conditional access apparatus of claim 6 , wherein: the agent establishment apparatus establishes a new entitlement agent in response to a third message of the further messages.
Claim 17
Dependent Claim
52 words
The conditional access apparatus of claim 15 , wherein: the agent establishment apparatus includes a first key representing a conditional access authority; and the agent establishment apparatus employs the first key to determine whether the third message is authentic and establishes the new entitlement agent only if the third message is authentic.
Claim 18
Dependent Claim
28 words
The conditional access apparatus of claim 6 , wherein: the entitlement specification apparatus specifies the given service entitlement in response to a fourth message of the further messages.
Claim 19
Dependent Claim
60 words
The conditional access apparatus of claim 17 , wherein: the entitlement specification apparatus includes a second key representing the entitlement agent; and the entitlement specification apparatus employs, if the third message is authentic, the second key to determine whether the fourth message is authentic and, in response to determining that the fourth message is authentic, further specifies the given entitlement.
Claim 20
Dependent Claim
88 words
The conditional access apparatus of claim 6 , wherein: the agent establishment apparatus includes other keys representing a conditional access authority; the agent establishment apparatus changes a first key of the plurality of keys in response to at least second and third messages of the further messages, the agent establishment apparatus using the other keys of the plurality of keys to determine whether the at least second and third messages are authentic and changing the other keys only when the at least second and third messages are authentic.
Claim 21
Dependent Claim
39 words
The conditional access apparatus of claim 19 , wherein the agent establishment apparatus both establishes and disestablishes the conditional access authority in accordance with use of the other keys and authentication of the at least second and third messages.
Claim 22
Dependent Claim
75 words
The conditional access apparatus of claim 1 , wherein: the receiver includes decryption apparatus for decrypting the instance of service; the second message contains a decryption value; the entitlement specification apparatus contains an additional key for the established entitlement agent; the access granting apparatus employs the additional key and the decryption value to obtain a decryption key for the instance of service; and the receiver uses the decryption key to decrypt the instance of service.
Claim 23
Dependent Claim
59 words
The conditional access apparatus of claim 21 , wherein: the additional key is a shared secret that the entitlement specification apparatus shares with the established entitlement agent; and the access granting apparatus uses the shared secret to determine whether the second message is authentic and grants access to the instance of service only if the second message is authentic.
Claim 24
Dependent Claim
53 words
The conditional access apparatus of claim 1 , wherein: the agent establishment apparatus, the entitlement specification apparatus, and the access granting apparatus are implemented in a secure element that includes storage for the entitlements and a processor, and wherein the storage is writable and accessible only to the processor of the secure element.
Claim 25
Dependent Claim
29 words
The conditional access apparatus of claim 1 , wherein: the agent establishing apparatus and the entitlement specification apparatus operate without interruption to currently-granted access to the instance of service.
Claim 26
Dependent Claim
17 words
The conditional access apparatus of claim 1 , wherein all authentication is performed using RSA digital signatures.
Claim 27
Dependent Claim
30 words
The conditional access apparatus of claim 1 , wherein the instance of service is a program from the set of programs consisting of video programs, audio programs and audio-video programs.
Claim 28
Dependent Claim
17 words
The conditional access apparatus of claim 1 , wherein the instance of service is an MPEG program.
Claim 29
Independent Claim
289 words
A method for providing a receiver, in a conditional access system, with an entitlement for an encrypted instance of service, wherein the instance of service is provided by a service provider to the conditional access system, the method comprising the steps of: receiving at the receiver a first message, the first message having an indicator associated with an entitlement agent included therein; processing in the receiver the first message to authenticate the first message and, to establish, in the receiver, the entitlement agent associated with the indicator of the first message, wherein only when the first message is authentic is the entitlement agent established, and the act of establishing the entitlement agent imposes constraints, in the receiver, on the established entitlement agent; wherein the entitlement agent is one of a plurality of entitlement agents that are associated with instances of services provided to the receiver, a conditional access authority assigns constraints that are imposed upon the established entitlement agent, the first message, which is from the conditional access authority, includes the constraints for the entitlement agent, and the act of establishing the entitlement agent includes imposing the constraints assigned by the conditional access authority on the established entitlement agent; receiving at the receiver a second message, the second message having a service entitlement specifier associated with the instance of service included therein; processing the second message to associate the service entitlement specifier with the established entitlement agent; receiving at the receiver the encrypted instance of service and a third message having an entitlement identifier included therein, wherein the entitlement identifier is associated with the instance of service; and processing in the receiver the third message to determine whether the receiver is entitled to decrypt the encrypted instance of service.
Claim 30
Independent Claim
289 words
A method for providing a receiver, in a conditional access system, with an entitlement for an encrypted instance of service, wherein the instance of service is provided by a service provider to the conditional access system, the method comprising the steps of: receiving at the receiver a first message, the first message having an indicator associated with an entitlement agent included therein; processing in the receiver the first message to authenticate the first message and, to establish, in the receiver, the entitlement agent associated with the indicator of the first message, wherein only when the first message is authentic is the entitlement agent established, and the act of establishing the entitlement agent imposes constraints, in the receiver, on the established entitlement agent; wherein the entitlement agent is one of a plurality of entitlement agents that are associated with instances of services provided to the receiver, a conditional access authority assigns constraints that are imposed upon the established entitlement agent, the first message, which is from the conditional access authority, includes the constraints for the entitlement agent, and the act of establishing the entitlement agent includes imposing the constraints assigned by the conditional access authority on the established entitlement agent; receiving at the receiver a second message, the second message having a service entitlement specifier associated with the instance of service included therein; processing the second message to associate the service entitlement specifier with the established entitlement agent; receiving at the receiver the encrypted instance of service and a third message having an entitlement identifier included therein, wherein the entitlement identifier is associated with the instance of service; and processing in the receiver the third message to determine whether the receiver is entitled to decrypt the encrypted instance of service.
Claim 31
Dependent Claim
30 words
The method of claim 28 , wherein the act of establishing includes the act of configuring at least a portion of the memory of receiver according to a predetermined configuration.
Claim 32
Dependent Claim
32 words
The method of claim 29 , wherein the predetermined configuration of the receiver memory is determined by the conditional access authority, and the first message includes information related to the predetermined configuration.
Claim 33
Dependent Claim
39 words
The method of claim 28 , wherein the act of determining further includes using at least the entitlement identifier and the service entitlement specifier to determine whether the receiver is entitled to decrypt the received encrypted instance of service.
Claim 34
Dependent Claim
34 words
The method of claim 28 , wherein the receiver includes a memory, and the constraints imposed on the established entitlement agent includes allocating a maximum amount of the memory to the established entitlement agent.
Claim 35
Dependent Claim
24 words
The method of claim 28 , wherein the constraints imposed on the established entitlement agent includes controlling the entitlements offered by the entitlement agent.
Claim 36
Dependent Claim
24 words
The method of claim 33 , wherein controlling the entitlements includes act of limiting the number of entitlements offered by the established entitlement agent.
Claim 37
Dependent Claim
25 words
The method of claim 34 , wherein controlling the entitlements includes the act of limiting the types of entitlements offered by the established entitlement agent.
Claim 38
Dependent Claim
65 words
The method of claim 28 , further including the steps of: receiving a fourth message having a second service entitlement specifier associated with the instance of service; and processing the fourth message to associate the second service entitlement specifier with the established entitlement agent, wherein the second service entitlement specifier specifies that the receiver is not entitled to decrypt the received encrypted instance of service.
Claim 39
Dependent Claim
53 words
The method of claim 28 , further including the step of: receiving at the fourth message; processing a fourth message to authenticate the fourth message and, only when the fourth message is authentic, to disestablish the established entitlement agent, whereupon the receiver is not entitled to decrypt the received encrypted instance of service.
Claim 40
Dependent Claim
46 words
The method of claim 37 , wherein the receiver includes memory, the entitlement agent has a portion of the memory allocated thereto for the established entitlement agent, and the act of disestablishing the established entitlement agent includes allocating none of the memory to the entitlement agent.
Claim 41
Dependent Claim
33 words
The method of claim 28 , wherein the act of establishing includes storing a public key of a private key-private key pair associated with the entitlement agent in a memory of the receiver.
Claim 42
Dependent Claim
112 words
The method of claim 39 , wherein the memory of the receiver has a first and at least a second public key stored therein, each public key being half of public key-private key pair, the first public key is associated with a conditional access authority that authorizes the establishment of the entitlement agent in the receiver, the first public key is used to authenticate the first message, the second public key is associated with the entitlement agent and is included in the first message, the second public key is stored in the memory only if the first message is authentic, and the second public key is used to authenticate the second message.
Claim 43
Dependent Claim
116 words
The method of claim 40 , further including the steps of: receiving at the receiver a fourth message having encrypted content and an authentication token included therein; using at least the authentication token of the fourth message to authenticate the source of the fourth message; decrypting the encrypted content of the fourth only when the source of the fourth message has been authenticated, and wherein the decrypted content of the fourth message includes a long-term key; using the long-term key and a portion of the fourth message to generate a short-term key, and using the short term key to decrypt the encrypted instance of service only when the receiver is entitled to the instance of service.
Claim 44
Dependent Claim
38 words
The method of claim 41 , wherein the memory of the receiver includes a private key of a public key-private key pair, and the receiver uses the private key to decrypt the encrypted content of the fourth message.
Claim 45
Dependent Claim
17 words
The method of claim 41 , wherein the source of the fourth message is the entitlement agent.
Claim 46
Dependent Claim
145 words
The method of claim 28 , wherein the receiver has a memory having a plurality of public keys associated a conditional access authority stored therein, wherein the conditional access authority authorizes the establishment of the entitlement agent, and each public key is part of a public key-private key pair, and further including the steps of: receiving a fourth message at the receiver having a content that includes a particular public key, an authentication token and a key indicator included therein; using a first public key of the plurality of public keys to authenticate the source of the fourth message; associating the key indicator with a given public key of the plurality of keys associated with the conditional access authority; replacing the given public key with the particular public key only when the conditional access authority is authenticated as the source of the third entitlement message.
Claim 47
Dependent Claim
77 words
The method of claim 44 , further including the steps of: using at least a portion of the content of the fourth message as an input into a hash function to produce an output hash; comparing the output hash with a portion of the authentication token of the fourth message, and wherein the given key is replaced by the particular key only when the compared portion of the authentication token is the same as the output hash.
Claim 48
Dependent Claim
153 words
The method of claim 45 , further including the steps of: receiving a fifth message at the receiver having a content that includes a second particular public key, an authentication token and a second key indicator included therein, wherein the second particular public key is the same as the particular public key included in the fourth message, and the second key indicator is the same as the key indicator included in the fourth message; using a second public key of the plurality of public keys to authenticate the source of the fifth message; using at least a portion of the content of the fifth message as an input into a hash function to produce a second output hash; comparing the second output hash with the first output hash, and wherein the given key is replaced by the particular key only when the second output hash is the same as the first output hash.
Claim 49
Dependent Claim
406 words
An entitling apparatus in a receiver, wherein the receiver is in a conditional access system and receives an encrypted instance of service, the instance of service is associated with an entitlement agent that is included in the conditional access system, the apparatus comprising: means for establishing entitlements in the receiver for the entitlement agent, wherein the establishing means establishes the entitlements in response to a first message, wherein the establishing means imposes constraints in the receiver on the entitlements for the entitlement agent; a memory, wherein at a portion of the memory is allocated to the entitlement agent, and the imposed constraints includes limiting the memory usage of the entitlement agent to the portion of the memory allocated to the entitlement agent, wherein the memory has a public key of a public key-private key pair stored therein, wherein the public key is used to authenticate the first message, the first message includes a second public key that is associated with the entitlement agent, and when the first message is authentic the second public key is stored in portion of the memory allocated to the entitlement agent; means for specifying service entitlements of the receiver, wherein the specifying means specifies the service entitlements of the receiver for the instances of service associated with the entitlement agent, and the service entitlements are specified in response to a second message; means for generating a decryption key to generate a key for decrypting the encrypted instance of service, wherein the decryption key generating means uses at least a long-term key to generate a short-term decryption key for the decrypting the encrypted instance of service, wherein the long-term key is included in a third message, which is authenticated by the second public key, and only when the second message is authentic is the long-term key used by the decryption key generating means; means for granting the decryption of the received encrypted instance of service, wherein the encrypted instance of service is associated with an entitlement identifier, and the granting is based at least in part on the entitlement identifier and at least in part on the specified service entitlement of the receiver for the instance of service, wherein the receiver receives a fourth message that is associated with the encrypted instance of service, the fourth message includes the entitlement identifier and a short-term key indicator, wherein the decryption key generating means uses the short-term indicator to generate the short-term decryption key.
Claim 50
Dependent Claim
406 words
An entitling apparatus in a receiver, wherein the receiver is in a conditional access system and receives an encrypted instance of service, the instance of service is associated with an entitlement agent that is included in the conditional access system, the apparatus comprising: means for establishing entitlements in the receiver for the entitlement agent, wherein the establishing means establishes the entitlements in response to a first message, wherein the establishing means imposes constraints in the receiver on the entitlements for the entitlement agent; a memory, wherein at a portion of the memory is allocated to the entitlement agent, and the imposed constraints includes limiting the memory usage of the entitlement agent to the portion of the memory allocated to the entitlement agent, wherein the memory has a public key of a public key-private key pair stored therein, wherein the public key is used to authenticate the first message, the first message includes a second public key that is associated with the entitlement agent, and when the first message is authentic the second public key is stored in portion of the memory allocated to the entitlement agent; means for specifying service entitlements of the receiver, wherein the specifying means specifies the service entitlements of the receiver for the instances of service associated with the entitlement agent, and the service entitlements are specified in response to a second message; means for generating a decryption key to generate a key for decrypting the encrypted instance of service, wherein the decryption key generating means uses at least a long-term key to generate a short-term decryption key for the decrypting the encrypted instance of service, wherein the long-term key is included in a third message, which is authenticated by the second public key, and only when the second message is authentic is the long-term key used by the decryption key generating means; means for granting the decryption of the received encrypted instance of service, wherein the encrypted instance of service is associated with an entitlement identifier, and the granting is based at least in part on the entitlement identifier and at least in part on the specified service entitlement of the receiver for the instance of service, wherein the receiver receives a fourth message that is associated with the encrypted instance of service, the fourth message includes the entitlement identifier and a short-term key indicator, wherein the decryption key generating means uses the short-term indicator to generate the short-term decryption key.
Claim 51
Dependent Claim
28 words
The apparatus of claim 47 , wherein the constraints in the receiver imposed on the entitlement agent include controlling the types of services associated with the entitlement agent.
Claim 52
Dependent Claim
24 words
The apparatus of claim 47 , wherein the constraints in the receiver imposed on the entitlement agent include limiting the number of service entitlements.
Claim 53
Dependent Claim
42 words
The apparatus of claim 47 , wherein in response to the third message the entitlement agent is allocated none of the memory of the receiver, and thereupon the receiver is not entitled to decrypted instances of service associated with the entitlement agent.
Claim 54
Dependent Claim
31 words
The apparatus of claim 47 , wherein the second public key is used to authenticate the second message, and only when the second message is authentic are the service entitlements specified.
Claim 55
Dependent Claim
32 words
The apparatus of claim 47 , wherein through the duration of the instance of service a plurality of different short term decryption keys are used for decrypting the encrypted instance of service.
References Cited (Backward Citations)
US4150404A
Cited
US4155042A
Cited
US4405829A
Cited
US4358672A
Cited
USRE33808E
Cited
US4388643A
Cited
USRE33189E
Cited
US4531020A
Cited
US4613901A
Cited
US4736422A
Cited
US4658093A
Cited
US4600921A
Cited
US4649533A
Cited
US4712238A
Cited
US4634807A
Cited
US4887296A
Cited
US5036537A
Cited
US4982430A
Cited
US4885777A
Cited
US5018196A
Cited
US4712239A
Cited
US4866770A
Cited
US4823385A
Cited
US4912762A
Cited
US4864615A
Cited
US5175765A
Cited
US5151782A
Cited
US5003591A
Cited
US5124117A
Cited
US5155591A
Cited
US5282249A
Cited
US4993068A
Cited
US5029207A
Cited
US5237610A
Cited
US5073935A
Cited
US5270822A
Cited
US5235643A
Cited
US5301233A
Cited
US5142578A
Cited
US5282248A
Cited
US5231665A
Cited
US5249230A
Cited
US5565909A
Cited
US5432542A
Cited
US5402490A
Cited
US5243652A
Cited
US5400401A
Cited
US5341425A
Cited
US5465299A
Cited
WO1994013107A1
Cited
US5381477A
Cited
US5588058A
Cited
US5285497A
Cited
US5381481A
Cited
US5506904A
Cited
US5414773A
Cited
US5440633A
Cited
US5524052A
Cited
US5499295A
Cited
US5497422A
Cited
US5343527A
Cited
US5488410A
Cited
US5481542A
Cited
US5499294A
Cited
US5519780A
Cited
US5425101A
Cited
US5787172A
Cited
US5420866A
Cited
US5481613A
Cited
WO1995029560A1
Cited
US5557678A
Cited
US5557765A
Cited
US5568552A
Cited
US5473692A
Cited
US5550984A
Cited
US5740246A
Cited
EP0723371A1
Cited
US5590202A
Cited
US5568554A
Cited
US5563950A
Cited
US5559889A
Cited
US6246767B1
Cited
US6105134A
Cited
US5742677A
Cited
US5621793A
Cited
US5583939A
Cited
EP0752786A1
Cited
US5671276A
Cited
US5764770A
Cited
US5675649A
Cited
US5857020A
Cited
US5870474A
Cited
US5862220A
Cited
US6005938A
Cited
US5920626A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2006-02-03 | 2006-08-05 | 2007-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-02-03 | 2010-08-05 | 2011-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-02-03 | 2014-08-05 | 2015-02-04 | $7700.00 | Window Closed / Lapsed |