Patent ID: 11909877
Assignee: KONINKLIJKE PHILIPS N.V.
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 16:
17. A private-key decryption method comprising:
establishing communication with a public-key encryption device;
generating a first private-key matrix;
computing a first public-key matrix from the first private-key matrix, and allow transfer of the first public-key matrix to the public-key encryption device;
receiving from the public-key encryption device an indication of a key size and/or matrix size;
receiving a second public-key matrix and a masked transmission key, wherein the second public-key matrix has fewer matrix elements than the first public-key matrix;
computing a first raw shared key from the second public-key matrix and the first private-key matrix;
computing the first raw shared key comprising a matrix multiplication between the second public-key matrix and the first private-key matrix; and
unmasking the masked transmission key in dependence on the received size using at least part of the first raw shared key to obtain a transmission key wherein the processor circuit is arranged to perform a handshake with the public-key encryption device, the handshape comprising:
sending to the public-key encryption device at least two indications of at least two first public-key matrices of the private-key decryption device, wherein the two first public-key matrices have different sizes;
receiving an indication of a selected first public-key matrix from the public-key encryption device;

sending the selected first public-key matrix, when a request for the selected first public-key matrix is received, wherein the transmission key is decapsulated with the selected first-public key.