Encryption method, cryptogram decoding method, encryptor, cryptogram decoder, and communication system

An encryption method comprising a modulation step for modulating one-bit input data into a coded signal by associating said one-bit input data with a discrete value determined by a pseudo random number and a physical random number and for generating said discrete value as said coded signal, wherein:

• 1) said coded signal can be demodulated into said input data by said pseudo random number;
• 2) the number of sets of said input data, said pseudo random number, and said physical random number corresponding to a particular value of said discrete value is equal in number for respective two values of said input data;
• and
• 3) the number of sets of said pseudo random number and said physical random number corresponding to respective values of said input data and respective values of said discrete value is equally associated also with any set of said input data and said discrete value;
• and
• wherein:
• said modulation step generates said coded signal premised that the number of states of said pseudo random number is 4, the number of states of said physical random number is 2, and the number of states of said discrete value is 4.

A cryptogram decoding method comprising:

• a channel decoding step for channel-decoding encrypted data into a decoded signal, said encrypted data being obtained by channel-encoding an output, obtained by performing modulation to associate one-bit input data with a discrete value of at least two bits determined by a pseudo random number and a physical random number, into a desired coded word, said modulation premising that:
• 1) said coded signal can be demodulated into said input data by said pseudo random number;
• 2) the number of sets of said input data, said pseudo random number, and said physical random number corresponding to a particular value of said discrete value is equal in number for respective two values of said input data;
• and
• 3) the number of sets of said pseudo random number and said physical random number corresponding to respective values of said input data and respective values of said discrete value is equally associated also with any set of said input data and said discrete value;
• and
• a demodulation step for demodulating said decoded signal into said input data by a pseudo random number based on the same encryption key as the encryption key having generated said pseudo random number used in said modulation.

A cryptogram decoding method comprising a demodulation step for demodulating a coded signal, said coded signal being obtained by performing modulation to associate one-bit input data with a discrete value determined by a pseudo random number and a physical random number, said modulation premising that:

• the number of states of said pseudo random number is 4, the number of states of said physical random number is 2, and the number of states of said discrete value is 4;
• and
• 1) said coded signal can be demodulated into said input data by said pseudo random number;
• 2) the number of sets of said input data, said pseudo random number, and said physical random number corresponding to a particular value of said discrete value is equal in number for respective two values of said input data;
• and
• 3) the number of sets of said pseudo random number and said physical random number corresponding to respective values of said input data and respective values of said discrete value is equally associated also with any set of said input data and said discrete value,
• wherein:
• said demodulation step demodulates said coded signal into said input data by a pseudo random number based on the same encryption key as the encryption key having generated said pseudo random number used in said modulation.

An encryptor comprising:

• a pseudo random number generation section for generating a pseudo random number based on an encryption key;
• a physical random number generation section for generating a physical random number based on a physical phenomenon;
• a modulation section for generating a coded signal by performing modulation to associate one-bit input data with a discrete value of at least two bits determined by said pseudo random number generated by said pseudo random number generation section and said physical random number generated by said physical random number generation section;
• and
• a channel coding section for channel-coding said coded signal generated by said modulation section into a desired coded word and outputting said coded signal channel-coded as encrypted data,
• wherein:
• 1) said coded signal can be demodulated into said input data by said pseudo random number;
• 2) the number of sets of said input data, said pseudo random number, and said physical random number corresponding to a particular value of said discrete value is equal in number for respective two values of said input data;
• and
• 3) the number of sets of said pseudo random number and said physical random number corresponding to respective values of said input data and respective values of said discrete value is equally associated also with any set of said input data and said discrete value.

An encryptor comprising:

• a pseudo random number generation section for generating a pseudo random number based on an encryption key;
• a physical random number generation section for generating a physical random number based on a physical phenomenon;
• and
• a modulation section for generating a coded signal by performing modulation to associate one-bit input data with a discrete value determined by said pseudo random number generated by said pseudo random number generation section and said physical random number generated by said physical random number generation section, wherein said modulation section premises that:
• the number of states of said pseudo random number is 4, the number of states of said physical random number is 2, and the number of states of said discrete value is 4;
• and
• 1) said coded signal can be demodulated into said input data by said pseudo random number;
• 2) the number of sets of said input data, said pseudo random number, and said physical random number corresponding to a particular value of said discrete value is equal in number for respective two values of said input data;
• and
• 3) the number of sets of said pseudo random number and said physical random number corresponding to respective values of said input data and respective values of said discrete value is equally associated also with any set of said input data and said discrete value.

An encryption method comprising a modulation step for modulating one-bit input data into a coded signal by associating said one-bit input data with a discrete value determined by a pseudo random number and a physical random number and for generating said discrete value as said coded signal,

• wherein:
• 1) said coded signal can be demodulated into said input data by said pseudo random number;
• 2) the number of sets of said input data, said pseudo random number, and said physical random number corresponding to a particular value of said discrete value is equal in number for respective two values of said input data;
• and
• 3) the number of sets of said pseudo random number and said physical random number corresponding to respective values of said input data and respective values of said discrete value is equally associated also with any set of said input data and said discrete value,
• wherein:
• said modulation step generates said coded signal premised that the state of said pseudo random number is one of four states, that is, 0, 1, 2, and 3, the state of said physical random number is one of two states, that is, 0 and 1, and the state of said discrete value is one of four states, that is, 0, 1, 2, and 3,
• wherein:
• if it is premised that a serial number given to each one bit of said input data is i, a number assigned to a set pattern of input data, a pseudo random number, a physical random number, and a discrete number is k (k is an integer from 0 through 15), said input data is Xk,i, said pseudo random number is rk,i, said physical random number is fk,i, and said discrete value is Sk,i, and when k is any one of integers from 0 through 7, said input data Xk,i=0;
• when k is any one of integers from 8 through 15, said input data xk,i=1;
• when k is any one of integers 0, 1, 8, and 9, said pseudo random number rk,i=0;
• when k is any one of integers 2, 3, 10, and 11, said pseudo random number rk,i=1;
• when k is any one of integers 4, 5, 12, and 13, said pseudo random number rk,i=2;
• when k is any one of integers 6, 7, 14, and 15, said pseudo random number rk,i=3;
• when k is an even number, said physical random number fk,i=0;
• and when k is an odd number, said physical random number fk,i=1, then a typical set Sj=(s0,i, s1,i, s2,i, s3,i, s4,i, s5,i, s6,i, s7,i, s8,i, s9,i, s10,i, s11,i, s12,i, s13,i, s14,i, s15,i) (j is an integer from 1 through 6) of said discrete value sk,i is
• S1=(0,1,0,1,2,3,2,3,2,3,2,3,0,1,0,1)
• S2=(0,1,0,2,1,3,2,3,2,3,1,3,0,2,0,1)
• S3=(0,1,0,3,1,2,2,3,2,3,1,2,0,3,0,1)
• S4=(0,2,0,2,1,3,1,3,1,3,1,3,0,2,0,2)
• S5=(0,2,0,3,1,2,1,3,1,3,1,2,0,3,0,2)
• S6=(0,3,0,3,1,2,1,2,1,2,1,2,0,3,0,3), and
• wherein:
• said modulation step generates said coded signal using any one of said six kinds of the typical sets S1 to S6.

A cryptogram decoder for demodulating a coded signal, said coded signal being obtained by performing modulation to associate one-bit input data with a discrete value determined by a pseudo random number and a physical random number, said modulation premising that:

• the number of states of said pseudo random number is 4, the number of states of said physical random number is 2, and the number of states of said discrete value is 4;
• and
• 1) said coded signal can be demodulated into said input data by said pseudo random number;
• 2) the number of sets of said input data, said pseudo random number, and said physical random number corresponding to a particular value of said discrete value is equal in number for respective two values of said input data;
• and
• 3) the number of sets of said pseudo random number and said physical random number corresponding to respective values of said input data and respective values of said discrete value is equally associated also with any set of said input data and said discrete value,
• into said input data:
• comprising:
• a demodulation pseudo random number generation section for generating demodulation pseudo random number based on the same encryption key as the encryption key having generated said pseudo random number used in said modulation;
• and
• a demodulation section for demodulating said coded signal into said input data by said demodulation pseudo random number generated by said demodulation pseudo random number generation section.

A communication system comprising:

• an encryptor configured so as to comprise a pseudo random number generation section for generating a random number based on an encryption key, a physical random number generation section for generating a physical random number based on a physical phenomenon, and a modulation section for generating a coded signal by performing modulation to associate one-bit input data with a discrete value of at least two bits determined by said pseudo random number generated by said pseudo random number generation section and said physical random number generated by said physical random number generation section, comprised in a sender communication device of said coded signal, and transmitting said coded signal to a destination communication device as a plurality of packets;
• and
• a cryptogram decoder configured so as to comprise a demodulation pseudo random number generation section for generating a demodulation pseudo random number based on the same encryption key having generated said pseudo random number used in said modulation and a demodulation section for demodulating said coded signal into said input data by said demodulation pseudo random number generated by said demodulation pseudo random number generation section, comprised in said destination communication device of said coded signal, and demodulating said coded signal in each packet received from said encryptor of said sender communication device into said input data,
• wherein:
• 1) said coded signal can be demodulated into said input data by said pseudo random number;
• 2) the number of sets of said input data, said pseudo random number, and said physical random number corresponding to a particular value of said discrete value is equal in number for respective two values of said input data;
• and
• 3) the number of sets of said pseudo random number and said physical random number corresponding to respective values of said input data and respective values of said discrete value is equally associated also with any set of said input data and said discrete value,
• wherein
• a serial number about said plurality of packets or said number of output times of pseudo random number used in said modulation of said coded signal in the container section of each packet is described in the header section of each packet to be transmitted from said encryptor to said cryptogram decoder;
• and
• wherein
• said cryptogram decoder comprises:
• a packet hold section for holding said plurality of packets from said encryptor;
• and
• a permutation section for permutating said plurality of packets held in said packet hold section into an order in accordance with said serial number or said number of output times described in the header section of each packet and inputting it to said demodulation section.