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

Claim 1:
2. A private-key decryption device comprising:
a communication interface circuit, wherein the communication interface circuit is arranged to communicate with a public-key encryption device; and
a processor circuit,
wherein the processor circuit is arranged to generate a first private-key matrix,
wherein the processor circuit is arranged to compute a first public-key matrix from the first private-key matrix,
wherein the processor circuit is arranged to allow transfer of the first public-key matrix to the public-key encryption device,
wherein the processor circuit is arranged to receive from the public-key encryption device an indication of a key size and/or matrix size, 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,
wherein the processor circuit is arranged to compute a first raw shared key from the second public-key matrix and the first private-key matrix,
wherein the processor circuit is arranged to compute the first raw shared key,
wherein the computing comprises a matrix multiplication between the second public-key matrix and the first private-key matrix,
wherein the processor circuit is arranged to unmask 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.