US5060266A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous cipher synchronization for cellular communication system
Assignee: Ericsson Inc
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Filing: 1990-07-20
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Granted: 1991-10-22
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Expires: 2010-07-20
Abstract
Abstract A system for the synchronization of encryption devices in a digital cellular communications system. Each of the encryption devices includes a multi-bit counter and generates a pseudo-random keystream which is combined with the data to be encrypted. The keystream is a function of the multi-bit counter value which is periodically incremented in response to a series of clock pulses. To allow proper decryption of the encrypted data, the system of the present invention provides continuous or very frequent updates of the transmitter counter value which may be used to reset the receiver counter and to resynchronize the system without the necessity of reinitialization and repetition of the intervening clock pulses.
Inventors
- 👤 Paul Dent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:28
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/24; H04B7/26; H04L; H04L9/00; H04L9/12; H04L9/06; H04L9/065; H04L9/0656; H04W; H04W12/00; H04W12/03; H04W12/033; H04L2209/00; H04L2209/80; H04W12/04
Claims Analysis
Total Claims: 66
Claim 1
Independent Claim
252 words
A method of communicating with cryptographically encoded data within a digital telecommunications system, comprising: generating a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to cryptographically encode said data; transmitting said encoded data to a receiver; transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register; generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; incrementing the value contained in said second register at the same defined intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream; combining the bits of the second pseudo-random key stream with the received stream of cryptographically encoded data to decode said data into said communications information; and periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 2
Independent Claim
252 words
A method of communicating with cryptographically encoded data within a digital telecommunications system, comprising: generating a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to cryptographically encode said data; transmitting said encoded data to a receiver; transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register; generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; incrementing the value contained in said second register at the same defined intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream; combining the bits of the second pseudo-random key stream with the received stream of cryptographically encoded data to decode said data into said communications information; and periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 3
Dependent Claim
61 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 1 which also includes: resetting the value contained in said second register with the received value of the first register for a corresponding moment in time when the values have become different to resynchronize the first and second key streams with one another.
Claim 4
Dependent Claim
58 words
A method of communicating with cryptographically encoded data within a digital telecommunications systems as set forth in claim 1 in which: said step of transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register includes multiplexing said encoded data transmissions and said transmissions of first register values.
Claim 5
Dependent Claim
40 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 3 in which: said first register values are transmitted on a low bit rate auxiliary channel of a digital cellular communications stream.
Claim 6
Dependent Claim
32 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 4 wherein: said low bit rate auxiliary channel is a slow associated control channel.
Claim 7
Dependent Claim
38 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 4 wherein: said first register values are transmitted along with other low-rate data on said low bit rate auxiliary channel.
Claim 8
Dependent Claim
45 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 6 in which: transmission of said first register values are temporarily interrupted when it is necessary to transmit other data on said low bit rate auxiliary channel.
Claim 9
Dependent Claim
44 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 3 in which components of each of said first register values multiplexed with said encoded data transmissions are dispersed within several successive blocks of transmitted data.
Claim 10
Dependent Claim
87 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 1 in which: said step of periodically comparing the value contained in said second register with the received value of the first register to determine whether two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another includes adding to the received value of the first register an incremental value to account for a time delay in transmission.
Claim 11
Dependent Claim
65 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 1 in which: the bits of the first pseudo-random key stream are combined with said stream of data bits carrying communications information by modulo-2 addition; and the bits of the second pseudo-random key stream are combined with the received stream of cryptographically encoded data by modulo-2 subtraction.
Claim 12
Dependent Claim
70 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 1 in which: the bits of the first pseudo-random key stream are combined with said stream of data bits carrying communications information to alter the order thereof; and the bits of the second pseudo-random key stream are combined with the received stream of cryptographically encoded data to restore the original order thereof.
Claim 13
Dependent Claim
41 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 1 in which the defined intervals with which the values contained in said first and second registers are incremented are regular and periodic.
Claim 14
Dependent Claim
41 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 1 in which the intervals with which the value contained in said first register are transmitted to said receiver are regular and periodic.
Claim 15
Dependent Claim
86 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 1 which includes the additional step of: receiving a plurality of values of said first register successively transmitted to said receiver; and comparing said plurality of successively received first register values with one another after allowing for the increment of time between the transmission of each value to determine the accuracy of transmission of the received first register values before comparing said value to said second register value.
Claim 16
Independent Claim
270 words
A system for communicating with cryptographically encoded data within a digital telecommunications system, comprising: means for generating a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; means for incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; means for combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to cryptographically encode said data; means for transmitting said encoded data to a receiver; means for transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register; means for generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; means for incrementing the value contained in said second register at the same defined intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream; means for combining the bits of the second pseudo-random key stream with the received stream of cryptographically encoded data to decode said data into said communications information; and means for periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 17
Independent Claim
270 words
A system for communicating with cryptographically encoded data within a digital telecommunications system, comprising: means for generating a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; means for incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; means for combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to cryptographically encode said data; means for transmitting said encoded data to a receiver; means for transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register; means for generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; means for incrementing the value contained in said second register at the same defined intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream; means for combining the bits of the second pseudo-random key stream with the received stream of cryptographically encoded data to decode said data into said communications information; and means for periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 18
Dependent Claim
63 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 15 which also includes: means for resetting the value contained in said second register with the received value of the first register for a corresponding moment in time when the values have become different to resynchronize the first and second key streams with one another.
Claim 19
Dependent Claim
60 words
A system for communicating with Cryptographically encoded data within a digital telecommunications system as set forth in claim 15 in which: said means for transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register includes means for multiplexing said encoded data transmissions and said transmissions of first register values.
Claim 20
Dependent Claim
40 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 17 in which: said first register values are transmitted on a low bit rate auxiliary channel of a digital cellular communications stream.
Claim 21
Dependent Claim
32 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 18 wherein: said low bit rate auxiliary channel is a slow associated control channel.
Claim 22
Dependent Claim
38 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 18 wherein: said first register values are transmitted along with other low-rate data on said low bit rate auxiliary channel.
Claim 23
Dependent Claim
47 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 20 which also includes: means for temporarily interrupting transmission of said first register values when it is necessary to transmit other data on said low bit rate auxiliary channel.
Claim 24
Dependent Claim
89 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 15 in which: said means for periodically comparing the value contained in said second register with the received value of the first register to determine whether two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another includes means for adding to the received value of the first register an incremental value to account for a time delay in transmission.
Claim 25
Dependent Claim
65 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 15 in which: the bits of the first pseudo-random key stream are combined with said stream of data bits carrying communications information by modulo-2 addition; and the bits of the second pseudo-random key stream are combined with the received stream of cryptographically encoded data by modulo-2 subtraction.
Claim 26
Dependent Claim
70 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 15 in which: the bits of the first pseudo-random key stream are combined with said stream of data bits carrying communications information to alter the order thereof; and the bits of the second pseudo-random key stream are combined with the received stream of cryptographically encoded data to restore the original order thereof.
Claim 27
Independent Claim
342 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system, comprising: generating at a first location a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to be sent from said first location to a second location to cryptographically encode said data stream and with a stream of cryptographically encoded data stream received from said second location; transmitting the data stream encoded at said first location to a receiver at said second location; transmitting to said receiver at said second location at intervals and interspersed with said transmissions of encoded data the value contained in said first register; generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; incrementing the value contained in said second register at the same defined intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream; combining the bits of the second pseudo-random key stream with the stream of cryptographically encoded data received at said second location to decode said data into said communications information and with a stream of data bits carrying communications information to be sent from said second location to said first location to cryptographically encode said data stream; transmitting the data stream encoded at the second location to a receiver at the first location; periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 28
Independent Claim
342 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system, comprising: generating at a first location a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to be sent from said first location to a second location to cryptographically encode said data stream and with a stream of cryptographically encoded data stream received from said second location; transmitting the data stream encoded at said first location to a receiver at said second location; transmitting to said receiver at said second location at intervals and interspersed with said transmissions of encoded data the value contained in said first register; generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; incrementing the value contained in said second register at the same defined intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream; combining the bits of the second pseudo-random key stream with the stream of cryptographically encoded data received at said second location to decode said data into said communications information and with a stream of data bits carrying communications information to be sent from said second location to said first location to cryptographically encode said data stream; transmitting the data stream encoded at the second location to a receiver at the first location; periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 29
Dependent Claim
62 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 25 which also includes: resetting the value contained in said second register with the received value of the first register for a corresponding moment in time when the values have become different to resynchronize the first and second key streams with one another.
Claim 30
Dependent Claim
59 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 25 in which: said step of transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register includes multiplexing said encoded data transmissions and said transmissions of first register values.
Claim 31
Dependent Claim
41 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 27 in which: said first register values are transmitted on a low bit rate auxiliary channel of a digital cellular communications stream.
Claim 32
Dependent Claim
33 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 28 wherein: said low bit rate auxiliary channel is a slow associated control channel.
Claim 33
Dependent Claim
39 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 28 wherein: said first register values are transmitted along with other low-rate data on said low bit rate auxiliary channel.
Claim 34
Dependent Claim
46 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 30 in which: transmission of said first register values are temporarily interrupted when it is necessary to transmit other data on said low bit rate auxiliary channel.
Claim 35
Dependent Claim
89 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 25 in which: said step of periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another includes adding to the received value of the first register an incremental value to account for a time delay in transmission.
Claim 36
Dependent Claim
66 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 25 in which: the bits of the first pseudo-random key stream are combined with said stream of data bits carrying communications information by modulo-2 addition; and the bits of the second pseudo-random key stream are combined with the received stream of cryptographically encoded data by modulo-2 subtraction.
Claim 37
Dependent Claim
41 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 25 in which the defined interval with which the values contained in said first and second registers are incremented are regular and periodic.
Claim 38
Dependent Claim
41 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 25 in which the interval with which the value contained in said first register are transmitted to said receiver are regular and periodic.
Claim 39
Independent Claim
363 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system, comprising: means for generating at a first location a first pseudorandom key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; means for incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; means for combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to be sent from said first location to a second location to cryptographically encode said data stream and with a stream of cryptographically encoded data stream received from said second location; means for transmitting the data stream encoded at said first location to a receiver at said second location; means for transmitting to said receiver at said second location at intervals and interspersed with said transmissions of encoded data the value contained in said first register; means for generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; means for incrementing the value contained in said second register at the same defined intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream; means for combining the bits of the second pseudo-random key stream with the stream of cryptographically encoded data received at said second location to decode said data into said communications information and with a stream of data bit carrying communications information to be sent from said second location to said first location to cryptographically encode said data stream; means for transmitting the data stream encoded at the second location to a receiver at the first location; and means for periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 40
Independent Claim
363 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system, comprising: means for generating at a first location a first pseudorandom key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; means for incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; means for combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to be sent from said first location to a second location to cryptographically encode said data stream and with a stream of cryptographically encoded data stream received from said second location; means for transmitting the data stream encoded at said first location to a receiver at said second location; means for transmitting to said receiver at said second location at intervals and interspersed with said transmissions of encoded data the value contained in said first register; means for generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; means for incrementing the value contained in said second register at the same defined intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream; means for combining the bits of the second pseudo-random key stream with the stream of cryptographically encoded data received at said second location to decode said data into said communications information and with a stream of data bit carrying communications information to be sent from said second location to said first location to cryptographically encode said data stream; means for transmitting the data stream encoded at the second location to a receiver at the first location; and means for periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 41
Dependent Claim
64 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 36 which also includes: means for resetting the value contained in said second register with the received value of the first register for a corresponding moment in time when the values have become different to resynchronize the first and second key streams with one another.
Claim 42
Dependent Claim
59 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 36 in which: said step of transmitting to said receiver at interval and interspersed with said transmissions of encoded data the value contained in said first register includes multiplexing said encoded data transmissions and said transmissions of first register values.
Claim 43
Dependent Claim
41 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 38 in which: said first register values are transmitted on a low bit rate auxiliary channel of a digital cellular communications stream.
Claim 44
Dependent Claim
33 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 39 wherein: said low bit rate auxiliary channel is a slow associated control channel.
Claim 45
Dependent Claim
39 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 39 wherein: said first register values are transmitted along with other low-rate data on said low bit rate auxiliary channel.
Claim 46
Dependent Claim
46 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 41 in which: transmission of said first register values are temporarily interrupted when it is necessary to transmit other data on said low bit rate auxiliary channel.
Claim 47
Dependent Claim
89 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system as set forth in claim 36 in which: said step of periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another includes adding to the received value of the first register an incremental value to account for a time delay in transmission.
Claim 48
Dependent Claim
66 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications systems as set forth in claim 36 in which: the bits of the first pseudo-random key stream are combined with said stream of data bits carrying communications information by modulo-2 addition; and the bits of the second pseudo-random key stream are combined with the received stream of cryptographically encoded data by modulo-2 subtraction.
Claim 49
Dependent Claim
41 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 36 in which the defined intervals with which the values contained in said first and second registers are incremented are regular and periodic.
Claim 50
Dependent Claim
41 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 36 in which the intervals with which the value contained in said first register are transmitted to said receiver are regular and periodic.
Claim 51
Independent Claim
188 words
A method of communicating with cryptographically encoded data within a digital telecommunications system, comprising: generating a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to cryptographically encode said data; transmitting said encoded data to a receiver; transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register; generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; combining the bits of the second pseudo-random key stream with the received stream of cryptographically encoded data to decode said data into said communications information; and periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 52
Independent Claim
188 words
A method of communicating with cryptographically encoded data within a digital telecommunications system, comprising: generating a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to cryptographically encode said data; transmitting said encoded data to a receiver; transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register; generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; combining the bits of the second pseudo-random key stream with the received stream of cryptographically encoded data to decode said data into said communications information; and periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 53
Dependent Claim
54 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 47 which also includes: resetting the value contained in said second register with the received value of the first register for a corresponding moment in time resynchronize the first and second key streams with one another.
Claim 54
Dependent Claim
86 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 48 which also includes: incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; and incrementing the value contained in said second register at the same intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream.
Claim 55
Independent Claim
202 words
A system for communicating with cryptographically encoded data within a digital telecommunications system, comprising: means for generating a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; means for combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to cryptographically encode said data; means for transmitting said encoded data to a receiver; means for transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register; means for generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; means for combining the bits of the second pseudo-random key streams with the received stream of cryptographically encoded data to decode said data into said communications information; and means for periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 56
Independent Claim
202 words
A system for communicating with cryptographically encoded data within a digital telecommunications system, comprising: means for generating a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; means for combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to cryptographically encode said data; means for transmitting said encoded data to a receiver; means for transmitting to said receiver at intervals and interspersed with said transmissions of encoded data the value contained in said first register; means for generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; means for combining the bits of the second pseudo-random key streams with the received stream of cryptographically encoded data to decode said data into said communications information; and means for periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 57
Dependent Claim
57 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 50 which also includes: means for resetting the value contained in said second register with the received value of the first register for a corresponding moment in time to resynchronize the first and second key streams with one another.
Claim 58
Dependent Claim
90 words
A system for communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 51 which also includes: means for incrementing the value contained in said first register at defined intervals to vary the pattrn of bits in the first key stream; and means for incrementing the value contained in said second register at the same intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream.
Claim 59
Independent Claim
278 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system, comprising: generating at a first location a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to be sent from said first location to a second location to cryptographically encode said data stream and with a stream of cryptographically encoded data stream received from said second location; transmitting the data stream encoded at said first location to a receiver at said second location; transmitting to said receiver at said second location at intervals and interspersed with said transmissions of encoded data the value contained in said first register; generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; combining the bits of the second pseudo-random key stream with the stream of cryptographically encoded data received at said second location to decode said data into said communications information and with a stream of data bits carrying communications information to be sent from said second location to said first location to cryptographically encode said data stream; transmitting the data stream encoded at the second location to a receiver at the first location; periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 60
Independent Claim
278 words
A method for duplex communication with cryptographically encoded data within a digital telecommunications system, comprising: generating at a first location a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to be sent from said first location to a second location to cryptographically encode said data stream and with a stream of cryptographically encoded data stream received from said second location; transmitting the data stream encoded at said first location to a receiver at said second location; transmitting to said receiver at said second location at intervals and interspersed with said transmissions of encoded data the value contained in said first register; generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; combining the bits of the second pseudo-random key stream with the stream of cryptographically encoded data received at said second location to decode said data into said communications information and with a stream of data bits carrying communications information to be sent from said second location to said first location to cryptographically encode said data stream; transmitting the data stream encoded at the second location to a receiver at the first location; periodically comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 61
Dependent Claim
55 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 53 which also includes: resetting the value contained in said second register with the received value of the first register for a corresponding moment in time to resynchronize the first and second key streams with one another.
Claim 62
Dependent Claim
86 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 54 which also includes: incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; and incrementing the value contained in said second register at the same intervals as said first register to vary the pattern of its in the second key stream in an identical fashion to the pattern of bits in the first key stream.
Claim 63
Independent Claim
294 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system, comprising: means for generating at a first location a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; means for combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to be sent from said first location to a second location to cryptographically encode said data stream and with a stream of cryptographically encoded data stream received from said second location; means for transmitting the data stream encoded at said first location to a receiver at said second location; means for transmitting to said receiver at said second location at intervals and interspersed with said transmissions of encoded data the value contained in said first register; means for generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; means for combining the bits of the second pseudo-random key stream with the stream of cryptographically encoded data received at said second location to decode said data into said communications information and with a stream of data bit carrying communications information to be sent from said second location to said first location to cryptographically encode said data stream; means for transmitting the data stream encoded at the second location to a receiver at the first location; and means for comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 64
Independent Claim
294 words
A system for duplex communication with cryptographically encoded data within a digital telecommunications system, comprising: means for generating at a first location a first pseudo-random key stream of bits in accordance with an algorithm which is a function of a multi-bit digital value contained in a first register; means for combining the bits of the first pseudo-random key stream with a stream of data bits carrying communications information to be sent from said first location to a second location to cryptographically encode said data stream and with a stream of cryptographically encoded data stream received from said second location; means for transmitting the data stream encoded at said first location to a receiver at said second location; means for transmitting to said receiver at said second location at intervals and interspersed with said transmissions of encoded data the value contained in said first register; means for generating a second pseudo-random key stream of bits in accordance with said algorithm which is a function of a multi-bit digital value contained in a second register; means for combining the bits of the second pseudo-random key stream with the stream of cryptographically encoded data received at said second location to decode said data into said communications information and with a stream of data bit carrying communications information to be sent from said second location to said first location to cryptographically encode said data stream; means for transmitting the data stream encoded at the second location to a receiver at the first location; and means for comparing the value contained in said second register with the received value of the first register to determine whether the two values correspond for corresponding moments of time and whether the first and second key streams are in synchronism with one another.
Claim 65
Dependent Claim
55 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 56 which also includes: resetting the value contained in said second register with the received value of the first register for a corresponding moment in time to resynchronize the first and second key streams with one another.
Claim 66
Dependent Claim
86 words
A method of communicating with cryptographically encoded data within a digital telecommunications system as set forth in claim 57 which also includes: incrementing the value contained in said first register at defined intervals to vary the pattern of bits in the first key stream; and incrementing the value contained in said second register at the same intervals as said first register to vary the pattern of bits in the second key stream in an identical fashion to the pattern of bits in the first key stream.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-21 | 1995-04-22 | 1995-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-21 | 1999-04-22 | 1999-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-21 | 2003-04-22 | 2003-10-22 | $7700.00 | Window Closed / Lapsed |