Combinational combiner cryptographic method and apparatus
First Claim
Patent Images
1. A method operational on an encrypting device for selectively securing symbol transmissions during a telephonic transaction, comprising:
- obtaining a plurality of input symbols from a dual tone multi-frequency (DTMF) signal, originating at a telephone device, for the telephonic transaction over a communication path between the telephone device and a destination device;
obtaining a pseudorandomly selected translation table, from a plurality of translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be encrypted;
translating the input symbols into corresponding output symbols using their corresponding translation table for each of the input symbols to individually encrypt each input symbol; and
transmitting the output symbols to the destination device as a dual tone multi-frequency (DTMF) output signal over the communication path.
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Abstract
Another feature provides an efficient encryption method that safeguards the security of encrypted symbols. Each plaintext symbol is encrypted by using a separate pseudorandomly selected translation table. Rather than pre-storing every possible permutation of symbols as translation tables, the translation tables may be efficiently generated on-the-fly based on a pseudorandom number and a symbol shuffling algorithm. A receiving device may similarly generate reverse translation tables on-the-fly to decrypt received encrypted symbols.
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Citations
47 Claims
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1. A method operational on an encrypting device for selectively securing symbol transmissions during a telephonic transaction, comprising:
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obtaining a plurality of input symbols from a dual tone multi-frequency (DTMF) signal, originating at a telephone device, for the telephonic transaction over a communication path between the telephone device and a destination device; obtaining a pseudorandomly selected translation table, from a plurality of translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be encrypted; translating the input symbols into corresponding output symbols using their corresponding translation table for each of the input symbols to individually encrypt each input symbol; and transmitting the output symbols to the destination device as a dual tone multi-frequency (DTMF) output signal over the communication path. - View Dependent Claims (2, 6, 36, 37, 38, 39, 40, 41, 42, 43)
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3. A method operational on an encrypting device, comprising:
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obtaining a plurality of input symbols; obtaining a pseudorandomly selected translation table, from a plurality of translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be encrypted; and translating the input symbols into corresponding output symbols using their corresponding translation table for each of the input symbols to individually encrypt each input symbol, wherein the plurality of input symbols is defined by a set of N symbols, where N is a positive integer and a translation table is a permutation of the N symbols, and the first pseudorandom number is obtained by generating a pseudorandom number for the first input symbol, where the pseudorandom number is k bits long and k is a positive integer; determining whether the pseudorandom number is within a maximum number Pmax, where Pmax is the largest multiple of N factorial that is less than a maximum threshold 2k; discarding the pseudorandom number if it is greater than the maximum number Pmax; obtaining different pseudorandom numbers for the first input symbol until an acceptable pseudorandom number is obtained that is less than or equal to the maximum number Pmax; and dividing the acceptable pseudorandom number modulo N factorial to obtain the first pseudorandom number. - View Dependent Claims (4, 5)
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7. An encryption device for selectively securing symbol transmissions during a telephonic transaction, comprising:
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means for obtaining a plurality of input from a dual tone multi-frequency (DTMF) signal, originating at a telephone device, for the telephonic transaction over a communication path between the telephone device and a destination device; means for obtaining a pseudorandomly selected translation table, from a plurality of translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be encrypted; means for translating the input symbols into corresponding output symbols using their corresponding translation table for each of the input symbols to individually encrypt each input symbol; and means for transmitting the output symbols to the destination device as a dual tone multi-frequency (DTMF) output signal over the communication path. - View Dependent Claims (8, 9, 10, 11)
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12. An encryption device for selectively securing symbol transmissions during a telephonic transaction, comprising:
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an input interface for receiving a dual tone multi-frequency (DTMF) signal, originating at a telephone device, the DTMF signal including an input symbol stream for the telephonic transaction over a communication path between the telephone device and a destination device; and a processing circuit coupled to the input interface, the processing circuit configured to obtain a plurality of input symbols from the input interface; obtain a pseudorandomly selected translation table, from a plurality of translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be encrypted; translate the input symbols into corresponding output symbols using their corresponding translation table for each of the input symbols to individually encrypt each input symbol; and an output interface coupled to the processing circuit for transmitting the output symbols as a dual tone multi-frequency (DTMF) output signal to the destination device over the communication path.
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13. An encryption device comprising:
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an input interface for receiving an input symbol stream; and a processing circuit coupled to the input interface, the processing circuit configured to obtain a plurality of input symbols from the input interface; obtain a pseudorandomly selected translation table, from a plurality of translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be encrypted; and translate the input symbols into corresponding output symbols using their corresponding translation table for each of the input symbols to individually encrypt each input symbol, wherein the plurality of input symbols is defined by a set of N symbols, where N is a positive integer and a translation table is a permutation of the N symbols, and the processing circuit is further configured to generate a pseudorandom number for the first input symbol, wherein the pseudorandom number is k bits long and k is a positive integer; determine whether the pseudorandom number is within a maximum number Pmax, where Pmax is the largest multiple of N factorial that is less than a maximum threshold 2k; discard the pseudorandom number if it is greater than the maximum number Pmax; obtain different pseudorandom numbers for the first input symbol until an acceptable pseudorandom number is obtained that is less than or equal to the maximum number Pmax; and divide the acceptable pseudorandom number modulo N factorial to obtain the first pseudorandom number. - View Dependent Claims (14, 15)
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16. A non-transitory machine-readable medium having one or more instructions operational for selectively securing symbol transmissions during a telephonic transaction, which when executed by a processor causes the processor to:
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obtain a plurality of input symbols from a dual tone multi-frequency (DTMF) signal, originating at a telephone device, for the telephonic transaction over a communication path between the telephone device and a destination device; obtain a pseudorandomly selected translation table, from a plurality of translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be encrypted; translate the input symbols into corresponding output symbols using their corresponding translation table for each of the input symbols to individually encrypt each input symbol; and transmit the output symbols to the destination device as a dual tone multi-frequency (DTMF) output signal over the communication path. - View Dependent Claims (17, 18, 19, 20)
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21. A method operational on a decryption device for decrypting symbols, comprising:
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obtaining a dual tone multi-frequency (DTMF) signal, originating at a telephone device, for a telephonic transaction over a communication path between the telephone device and a destination device, the DTMF signal including a plurality of input symbols defined within a set of n symbols; obtaining a pseudorandomly selected reverse translation table, from a plurality of reverse translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be decrypted; and translating the input symbols into corresponding output symbols using their corresponding reverse translation table for each of the input symbols to individually decrypt each input symbol. - View Dependent Claims (22, 24, 44, 45, 46, 47)
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23. A method operational on a decryption device for decrypting symbols, comprising:
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obtaining a plurality of input symbols defined within a set of n symbols; obtaining a pseudorandomly selected reverse translation table, from a plurality of reverse translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be decrypted; and translating the input symbols into corresponding output symbols using their corresponding reverse translation table for each of the input symbols to individually decrypt each input symbol, wherein the plurality of input symbols is defined by a set of N symbols, where N is a positive integer and a reverse translation table is a permutation of the N symbols, and the first pseudorandom number is obtained by generating a pseudorandom number for the first input symbol, wherein the pseudorandom number is k bits long and k is a positive integer; determining whether the pseudorandom number is within a maximum number Pmax, where Pmax is the largest multiple of N factorial that is less than a maximum threshold 2k; discarding the pseudorandom number if it is greater than the maximum number Pmax; obtaining different pseudorandom numbers for the first input symbol until an acceptable pseudorandom number is obtained that is less than or equal to the maximum number Pmax; and dividing the acceptable pseudorandom number modulo N factorial to obtain the first pseudorandom number.
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25. A decryption device, comprising:
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means for obtaining a dual tone multi-frequency (DTMF) signal, originating at a telephone device, for a telephonic transaction over a communication path between the telephone device and a destination device, the DTMF signal including a plurality of input symbols defined within a set of n symbols; means for obtaining a pseudorandomly selected reverse translation table, from a plurality of reverse translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be decrypted; and means for translating the input symbols into corresponding output symbols using their corresponding reverse translation table for each of the input symbols to individually decrypt each input symbol. - View Dependent Claims (26, 27, 28)
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29. A decryption device, comprising:
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an input interface for receiving a dual tone multi-frequency (DTMF) signal, originating at a telephone device, for a telephonic transaction over a communication path between the telephone device and a destination device, the DTMF signal including an input symbol stream; and a processing circuit coupled to the input interface, the processing circuit configured to obtain a plurality of input symbols defined within a set of n symbols; obtain a pseudorandomly selected reverse translation table, from a plurality of reverse translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be decrypted; and translate the input symbols into corresponding output symbols using their corresponding reverse translation table for each of the input symbols to individually decrypt each input symbol. - View Dependent Claims (30, 32)
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31. A decryption device, comprising:
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an input interface for receiving an input symbol stream; and a processing circuit coupled to the input interface, the processing circuit configured to obtain a plurality of input symbols defined within a set of n symbols; obtain a pseudorandomly selected reverse translation table, from a plurality of reverse translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be decrypted; and translate the input symbols into corresponding output symbols using their corresponding reverse translation table for each of the input symbols to individually decrypt each input symbol, wherein the plurality of input symbols is defined by a set of N symbols, where N is a positive integer and a reverse translation table is a permutation of the N symbols and the processing circuit is further configured to generate a pseudorandom number for the first input symbol, wherein the pseudorandom number is k bits long and k is a positive integer; determine whether the pseudorandom number is within a maximum number Pmax, where Pmax is the largest multiple of N factorial that is less than a maximum threshold 2k; discard the pseudorandom number if it is greater than the maximum number Pmax; obtain different pseudorandom numbers for the first input symbol until an acceptable pseudorandom number is obtained that is less than or equal to the maximum number Pmax; and divide the acceptable pseudorandom number modulo N factorial to obtain the first pseudorandom number.
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33. A non-transitory machine-readable medium having one or more instructions for decrypting symbols, which when executed by a processor causes the processor to:
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obtain a dual tone multi-frequency (DTMF) signal, originating at a telephone device, for a telephonic transaction over a communication path between the telephone device and a destination device, the DTMF signal including a plurality of input symbols defined within a set of n symbols; obtain a pseudorandomly selected reverse translation table, from a plurality of reverse translation tables defining different symbol-to-symbol permutations, for each of the input symbols to be decrypted; and translate the input symbols into corresponding output symbols using their corresponding reverse translation table for each of the input symbols to individually decrypt each input symbol. - View Dependent Claims (34, 35)
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Specification