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US 11,115,183 B2Granted
Terminal device performing homomorphic encryption, server device processing ciphertext and methods thereof
AssigneeCrypto Lab Inc.
InventorsJung Hee Cheon, Duhyeong Kim, Yongsoo Song, Kyoohyung Han
Life of this patent
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Abstract
A decryption method includes: receiving a homomorphic ciphertext; and obtaining a result value added an error value at a message from the received homomorphic ciphertext. The error is disposed on the least significant bit (LSB) side in the homogeneous ciphertext, and the message is disposed at a position adjacent to the error.
Claims11
A decryption method, the method comprising:
- receiving a homomorphic ciphertext;
- and
- obtaining a result value added an error value at a message from the received homomorphic ciphertext,
- wherein the error is disposed on the least significant bit (LSB) side in the result value, and the message is disposed at a position adjacent to the error,
- wherein the homomorphic ciphertext is generated by reflecting a scaling factor in a message, and
- wherein the result value is obtained by multiplying an error value by a value in which the scaling factor is reflected in the message, and
- wherein a modulus of the homomorphic ciphertext is a value obtained by multiplying a plurality of different scaling factors by each other, and the plurality of different scaling factors are set as values which are disjoint from each other.
4 more elements
A terminal device, comprising:
- a memory configured to store a homomorphic ciphertext;
- and
- a processor configured to obtain a result value added an error value at a message from the homomorphic ciphertext,
- wherein the error is disposed on the least significant bit (LSB) side in the result value, and the message is disposed at a position adjacent to the error,
- wherein the homomorphic ciphertext is generated by reflecting a scaling factor in a message, and
- wherein the result value is obtained by multiplying an error value by a value in which the scaling factor is reflected in the message, and
- wherein a modulus of the homomorphic ciphertext is a value obtained by multiplying a plurality of different scaling factors by each other, and the plurality of different scaling factors are set as values which are disjoint from each other.
4 more elements
A non-transitory computer readable recording medium including a program for executing a decryption method,
- wherein the method comprises:
- receiving a homomorphic ciphertext;
- and
- obtaining a result value added an error value at a message from the received homomorphic ciphertext, and
- wherein the error is disposed on the least significant bit (LSB) side in the result value, and the message is disposed at a position adjacent to the error,
- wherein the homomorphic ciphertext is generated by reflecting a scaling factor in a message, and
- wherein the result value is obtained by multiplying an error value by a value in which the scaling factor is reflected in the message, and
- wherein a modulus of the homomorphic ciphertext is a value obtained by multiplying a plurality of different scaling factors by each other, and the plurality of different scaling factors are set as values which are disjoint from each other.
5 more elements
Dependencies are inferred from the claim text.