Method and apparatus for obtaining input of secure multiparty computation protocol

A system for privacy protection, wherein the system acts as a first computer device and comprises one or more processors and one or more non-transitory computer-readable memories coupled to the one or more processors and configured with instructions executable by the one or more processors to cause the system to perform operations comprising:

• obtaining a plurality of object IDs, wherein the plurality of object IDs include a target object ID;
• sending the plurality of object IDs to a second computer device storing a plurality of pieces of data respectively associated with the plurality of object IDs for the second computer device to generate a plurality of ciphertexts respectively based on the plurality of pieces of data, wherein the plurality of ciphertexts generated by the second computer device comprise a ciphertext associated with the target object ID and one or more different ciphertexts associated with one or more different object IDs of the plurality of object IDs;
• by executing a cryptography protocol with the second computer device;
• obtaining the ciphertext associated with the target object ID from the plurality of ciphertexts generated by the second computer device without obtaining the one or more different ciphertexts,
• wherein which of the plurality of object IDs being the target object ID obtained by the first computer device is unknown to the second computer device, and
• wherein the first computer device is unable to decrypt the ciphertext to determine the plurality of pieces of data;
• and
• sending the obtained ciphertext associated with the target object ID to a third computer device as an input to a secure multiparty computation protocol while concealing the target object ID from the third computer device.

A method for privacy protection, wherein the method is performed by a second computer device and comprises:

• receiving a plurality of object IDs from a first computer device, wherein the plurality of object IDs include a target object ID;
• encrypting a plurality of pieces of data respectively associated with the plurality of object IDs to generate a plurality of ciphertexts respectively associated with the plurality of object IDs, wherein the generated plurality of ciphertexts comprise a ciphertext associated with the target object ID and one or more different ciphertexts associated with one or more different object IDs of the plurality of object IDs;
• and
• executing a cryptography protocol with the first computer device for the first computer device to obtain the ciphertext associated with the target object ID from the plurality of ciphertexts without obtaining the one or more different ciphertexts,
• wherein which of the plurality of object IDs being the target object ID obtained by the first computer device is unknown to the second computer device, and
• wherein the first computer device is unable to decrypt the ciphertext to determine the plurality of pieces of data.