Encryption device, encryption method, decryption device and decryption method

An encryption method comprising:

• performing a conversion function having a predetermined relationship that outputs a plurality of output values configured of plain text according to a plurality of input values configured of plain text, wherein the plurality of input values are divided into parts of the plain text and the plurality of output values are converted into parts, with a part of the plurality of output values being inputted to a trapdoor one-way function, the predetermined relationship being defined by which converted parts of the plurality of output values are not inputted to the trapdoor one-way function and one arbitrary input value of the plurality of input values;
• and
• performing the trapdoor function having a property of encrypting the part of the plurality of output values according to the trapdoor one-way function, and the trapdoor one-way function not being able to decrypt encrypted data in a state in which a trapdoor is unknown.

A decryption device comprising:

• hardware configured to decrypt a plurality of input values configured of plain text and outputs a plurality of output values configured of plain text, wherein the plurality of input values are divided into parts of the plain text and the plurality of output values are converted into parts,
• wherein the hardware performs decryption by an inverse operation of a conversion function having a predetermined relationship that outputs the plurality of output values according to the plurality of input values configured of plain text, with a part of the plurality of output values being inputted to a trapdoor one-way function, the predetermined relationship being defined by which converted parts of the plurality of output values are not inputted to the trapdoor one-way function and one arbitrary input value of the plurality of input values,
• wherein the trapdoor one-way function has a property of encrypting the part of the plurality of output values, and not being able to decrypt encrypted data in a state in which a trapdoor is unknown.

A decryption method, comprising:

• decrypting a plurality of input values configured of plain text and outputting a plurality of output values configured of plain text, wherein the plurality of input values are divided into parts of the plain text and the plurality of output values are converted into parts,
• wherein the decryption method performs decryption by an inverse operation of a conversion function having a predetermined relationship that outputs the plurality of output values according to the plurality of input values configured of plain text, with a part of the plurality of output values being inputted to a trapdoor one-way function, the predetermined relationship being defined by which converted parts of the plurality of output values are not inputted to the trapdoor one-way function and one arbitrary input value of the plurality of input values, and
• wherein the trapdoor one-way function has a property of encrypting the part of the plurality of output values, and not being able to decrypt encrypted data in a state in which a trapdoor is unknown.