System and method for secure decryption using multi-party computation

A system for secure decryption of an encrypted message, the system comprising:

• a set of computer systems, wherein each computer system in the set of computer systems comprises a memory and a processor and stores a respective private share of a set of shares of a secret decryption key;
• and
• wherein each computer system in the set of computer systems is to:
• compute a decryption share of the encrypted message using the private share of the secret decryption key;
• compute a modified decryption share by removing a noise share from the decryption share;
• and
• wherein one or more of the computer systems in the set of computer systems is to recover a decrypted message by aggregating a plurality of the modified decryption shares, wherein the modified decryption shares are transmitted among the computer systems over a communication network, and wherein the noise shares are not transmitted among the computer systems over the communication network.

A method of computerized decryption, the method comprising:

• by each computer device of a set of computer devices, wherein each computer device comprises a memory and a processor and stores a respective share of a set of shares of a secret key:
• computing a decryption share of a cyphertext using the respective share of the secret key;
• computing a modified decryption share by stripping a noise share from the decryption share;
• and
• reconstructing, by one or more of the computer devices, a plaintext by combining a plurality of the modified decryption shares, wherein the modified decryption shares are transmitted among the computer devices over a data network, and wherein the noise shares are not transmitted among the computer devices over the data network.