Enciphering/deciphering apparatus and method incorporating random variable and keystream generation
First Claim
1. An enciphering apparatus comprising:
- chaos generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map;
bit generation means for normalizing individual real values in said real-valued sequence over a predetermined interval and for binarizing said normalized real values using values indicated by a predetermined number of second common keys as thresholds to generate a binary sequence; and
logic operation means for executing a predetermined logic operation on a binary sequence of an input plaintext and said generated keystream sequence bit by bit to generate a binary sequence of ciphertext.
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Abstract
An enciphering apparatus embodying this invention comprises chaos generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map, bit generation means for performing predetermined binarization on each real value in the generated real-valued sequence based on a predetermined number of second common keys to generate a binary sequence, and logic operation means for executing a predetermined logic operation on a binary sequence of an input plaintext and the generated keystream sequence bit by bit to generate a binary sequence of a ciphertext. For example, the first common keys are an initial seed of a nonlinear map and a value of a parameter k, and the bit generation means acquires plural pieces of binary data for each real value in the real-valued sequence using values indicated by a plurality of second keys as thresholds and obtains exclusive OR of those binary data.
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Citations
78 Claims
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1. An enciphering apparatus comprising:
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chaos generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map; bit generation means for normalizing individual real values in said real-valued sequence over a predetermined interval and for binarizing said normalized real values using values indicated by a predetermined number of second common keys as thresholds to generate a binary sequence; and logic operation means for executing a predetermined logic operation on a binary sequence of an input plaintext and said generated keystream sequence bit by bit to generate a binary sequence of ciphertext. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A keystream generating method for a keystream generating apparatus for use in a stream enciphering apparatus or a stream deciphering apparatus for performing a logic operation on a binary sequence of a plaintext or a ciphertext and a keystream sequence generated based on a predetermined common key to generate a ciphertext or an original plaintext, said keystream generating method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a Chebyshev map of degree k (k;
being a real value equal to or greater than
2) given by a differential equation ω
n+1 =cos (k cos-1 ω
n), the first common keys being an initial seed ω
0 of the Chebyshev map where -1<
ω
0 <
1, and a value of the parameter k; andperforming predetermined binarization on each real value in said generated real-valued sequence based on a predetermined number of second common keys to generate a binary sequence. - View Dependent Claims (16)
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17. A random variable generating method in a stream enciphering system based on a chaotic binary sequence comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map; normalizing individual real values in said real-valued sequence over a predetermined interval and binarizing said normalized real values using values indicated by a predetermined number of second common keys as thresholds to generate a binary sequence; and executing a predetermined logic operation on a binary sequence of an input plaintext and said generated keystream sequence bit by bit to generate a random variable. - View Dependent Claims (18, 19, 20)
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21. A random variable generating method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map with a given real value as an initial seed; performing binarization on each real value in said generated real-valued sequence with given 2M+1 (M being an integer equal to or greater than
1) values as thresholds to generate 2M+1 binary sequences, said 2M+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take; andexecuting a predetermined logic operation based on said generated 2M+1 binary sequences to generate random variables. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. An enciphering apparatus comprising:
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real-valued sequence generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map using a real value, indicated by a first common key, as an initial seed; binarization means for performing binarization on each real value in said generated real-value sequence with 2M+1 (M being an integer equal to or greater than
1) values indicated by a second common key as thresholds to generate 2M+1 binary sequence, said 2M+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take;first logic operation means for executing a predetermined first logic operation based on said generated 2M +1 binary sequences to generate a keystream sequence; and second logic operation means for executing a predetermined second logic operation based on a binary sequence of a plaintext and said keystream sequence to generate a binary sequence of a ciphertext. - View Dependent Claims (29, 30, 31, 33, 34, 35, 36, 37, 39, 40, 41, 42, 43, 45, 46, 47, 48, 49, 51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62, 63, 64)
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32. An enciphering apparatus comprising:
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real-valued sequence generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map having an equidistributivity of the invariant measure, symmetric property of the invariant measure and symmetric property of the map, using a real value, indicated by a first common key, as an initial seed; binarization means for performing binarization on each real value in said generated real-valued sequence with 2M+1 (M being an integer equal to or greater than
1) values indicated by a second common key as thresholds to generate 2M+1 binary sequences;first exclusive OR means for performing an exclusive OR of said generated 2M+1 binary sequences to generate a keystream sequence; and second exclusive OR means for performing an exclusive OR of a binary sequence of a plaintext and said keystream sequence to generate a binary sequence of a ciphertext, whereby a binary sequence of ideal random variables is generated by using, as said nonlinear map, one having an equidistributivity of the invariant measure, symmetric property of the invariant measure and symmetric property of the map, and permitting said 2M+1 thresholds tr (r=0 to 2M) to satisfy relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take. - View Dependent Claims (38, 44, 50, 56)
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65. An enciphering method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map having an equidistributivity of the invariant measure, symmetric property of the invariant measure and symmetric property of the map, using a real value, indicated by a first common key, as an initial seed; performing binarization on each real value in said generated real-valued sequence with 2M+1 (M being an integer equal to or greater than
1) values indicated by a second common key as thresholds to generate 2M+1 binary sequences;performing an exclusive OR of said generated 2M+1 binary sequences to generate a keystream sequence; and performing an exclusive OR of a binary sequence of a plaintext and said keystream sequence to generate a binary sequence of a ciphertext, whereby a binary sequence of ideal random variables is generated by using, as said nonlinear map, one having an equidistributivity of the invariant measure, symmetric property of the invariant measure and symmetric property of the map, and permitting said 2M+1 thresholds tr (r=0 to 2M) to satisfy relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take.
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66. A deciphering apparatus, comprising:
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chaos generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map; bit generation means for normalizing individual real values in said real-valued sequence over a predetermined interval and for binarizing said normalized real values using values indicated by a predetermined number of second common keys as thresholds to generate a binary sequence; and means for executing a predetermined logic operation on a binary sequence of an input ciphertext and said generated keystream sequence bit by bit to generate a binary sequence of an original ciphertext.
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67. A keystream generating apparatus for use in a stream enciphering apparatus or a stream deciphering apparatus for performing a logic operation on a binary sequence of a plaintext or a ciphertext and a keystream sequence generated based on a predetermined common key to generate a ciphertext or an original plaintext, said keystream generating apparatus comprising:
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chaos generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map; and bit generation means for normalizing individual real values in said real-valued sequence over a predetermined interval and for binarizing said normalized real values using values indicated by a predetermined number of second common keys as thresholds to generate to binary sequence.
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68. An enciphering method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map; normalizing individual real values in said real-valued sequence over a predetermined interval and binarizing said normalized real values using values indicated by a predetermined number of second common keys as thresholds to generate to binary sequence; and executing a predetermined logic operation on a binary sequence of an input plaintext and said generated keystream sequence bit by bit to generate a binary sequence of a ciphertext.
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69. A deciphering method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map; normalizing individual real values in said real valued sequence over a predetermined interval and binarizing said normalized real values using values indicated by a predetermined number of second common keys as thresholds to generate a binary sequence; and executing a predetermined logic operation on a binary sequence of an input ciphertext and said generated keystream sequence bit by bit to generate a binary sequence of an original plain text.
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70. A keystream generating method for a keystream generating apparatus for use in a stream for use in a stream enciphering apparatus or a stream deciphering apparatus for performing a logic operation on a binary sequence of a plaintext or a ciphertext and a keystream sequence generated based on a predetermined common key to generate a ciphertext or an original plaintext, said keystream generating method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map and normalizing individual real values in said real-valued sequence over a predetermined interval and binarizing said normalized real values using values indicated by a predetermined number of second common keys as thresholds to generate a binary sequence.
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71. A computer readable storage medium storing a program for generating a random variable and for controlling a computer, said program comprising:
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a computer readable program code means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined number of first common keys and a predetermined nonlinear map; a computer readable program code means for normalizing individual real values in said real-valued sequence over a predetermined interval and binarizing said normalized real values using values indicated by a predetermined number of second common keys to generate to binary sequence; and a computer readable program code means for executing a predetermined logic operation on a binary sequence of an input plaintext and the generated keystream sequence bit by bit to generate a binary sequence of a ciphertext.
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72. A random variable generating apparatus comprising:
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real-valued sequence generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map with a given real value as an initial seed; binarization means for performing binarization on each real value in said generated real-valued sequence with given 2M+1 (M being an integer equal to or greater than
1) values as thresholds to generate 2M+1 binary sequence, said 2M+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take; andlogic operation means for executing a predetermined logic operation based on said generated 2M+1 binary sequence to generate random variables.
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73. A storage medium readable by a computer and having stored a program for generating random variables and controlling said computer in such a manner as to generate a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map with a given real value as an initial seed;
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perform binarization on each real value in said generated real-valued sequence with given 2M+1 (M being an integer equal to or greater than
1) values as thresholds to generate 2M+1 binary sequences, said 2M+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take; andexecute a predetermined logic operation based on said generated 2M+1 binary sequence to generate random variables.
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74. A deciphering apparatus comprising:
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real-valued sequence generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map using a real value, indicated by a first common key, as an initial seed; binary sequence generation means for performing binarization on each real value in said generated real-valued sequence with 2M+1 ( M being an integer equal to or greater than
1) values indicated by a second common key as thresholds to generate 2M+1 binary sequences, said 2M+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take;first logic operation means for executing a predetermined first logic operation based on said generated 2M+1 binary sequences to generate a keystream sequence; and second logic operation means for executing a predetermined second logic operation based on a binary sequence of a ciphertext and said keystream sequence to generate a binary sequence of a plaintext.
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75. A keystream generating apparatus for use in a stream enciphering apparatus or a stream deciphering apparatus for performing a logic operation on a binary sequence of a plaintext or a ciphertext and a keystream sequence generated based on a predetermined common key to generate a ciphertext or an original plaintext, said keystream generating apparatus comprising:
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real-valued sequence generation means for generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map using a real value, indicated by a first common key, as an initial seed; binary sequence generation means for performing binarization on each real value in said generated real-valued sequence with 2M+1 (M being an integer equal to or greater than
1) values indicated by a second common key as thresholds to generate 2M+1 binary sequences, said 2M+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take; andlogic operation means for executing a predetermined logic operation based on said generated 2M+1 binary sequences to generate a keystream sequence.
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76. An enciphering method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map using a real value, indicated by a first common key, as an initial seed; performing binarization on each real value in said generated real-valued sequence with 2M+1 (M being an integer equal to or greater than
1) values indicated by a second common key as thresholds to generate 2M+1 binary sequence, said 2M=+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take;executing a predetermined first logic operation based on said generated 2M+1 binary sequences to generate a keystream sequence; and executing a predetermined second logic operation based on a binary sequence of a plaintext and said keystream sequence to generate a binary sequence of a ciphertext.
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77. A deciphering method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map using a real value, indicated by first common key, as an initial seed; performing binarization on each real value in said generated real-valued sequence with 2M +1 (M being an integer equal to or greater than
1) values indicated by a second common key as thresholds to generate 2M+1 binary sequences, said 2M+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take;executing a predetermined first logic operation based on said generated 2M+1 binary sequences to generate a keystream sequence; and executing a predetermined second logic operation based on a binary sequence of a ciphertext and said keystream sequence to generate a binary sequence of a plaintext.
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78. A keystream generating method in a keystream generating apparatus for use in a stream enciphering apparatus or a stream deciphering apparatus for performing a logic operation on a binary sequence of a plaintext or a ciphertext and a keystream sequence generated based on a predetermined common key to generate a ciphertext or an original plaintext, said keystream generating method comprising the steps of:
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generating a real-valued sequence along a chaotic orbit in accordance with a predetermined nonlinear map using a real value, indicated by a first common key, as an initial seed; performing binarization on each real value in said generated real-valued sequence with 2M+1 (M being an integer equal to or greater than
1) values indicated by a second common key as thresholds to generate 2M+1 binary sequences, said 2M+1 thresholds tr (r=0 to 2M) satisfying relationships tr +t2M-r =d+e and ti ≠
tj (when i≠
j) where d and e are respectively a minimum value and a maximum value said nonlinear map can take; andexecuting a predetermined logic operation based on said generated 2M+1 binary sequences to generate a keystream sequence.
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Specification