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

Claim 0:
1. A public-key encryption device comprising:
a communication interface circuit, wherein the communication interface circuit is arranged to communicate with a private-key decryption device; and
a processor circuit,
wherein the processor circuit is arranged to obtain a first public-key matrix,
wherein the public-key matrix is associated with the private-key decryption device,
wherein the processor circuit is arranged to obtain a key size for a transmission key,
wherein the processor circuit is arranged to generate the transmission key according to the key size,
wherein the processor circuit is arranged to determine a matrix size for a second private-key matrix,
wherein the matrix size is arranged to accommodate masking of the transmission key,
wherein the processor circuit is arranged to generate the second private-key matrix according to the matrix size,
wherein the processor circuit is arranged to compute a second public-key matrix from the second private-key matrix,
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 second raw shared key from the second private-key matrix and the first public-key matrix,
wherein computing the second raw shared key comprises a matrix multiplication between the second private-key matrix and the first public-key matrix,
wherein the processor circuit is arranged to mask the transmission key with at least part of the second raw shared key,
wherein the processor circuit is arranged to transfer an indication of the key size and/or matrix size, the second public-key matrix, and the masked transmission key to the private-key decryption device
wherein the processor circuit is arranged to perform a handshake with the private-key decryption device, the handshake comprising:
receiving at least two indications of at least two first public-key matrices of the private-key decryption device from the private-key decryption device,
wherein the two first public-key matrices have different sizes;
selecting the larger of the first public-key matrix and the second public-key matrix;
sending an indication of the selected first public-key matrix to the private-key decrypting device; and
requesting the first public-key matrix when the first public-key matrix is not available in a key-cache, wherein the transmission key is encapsulated with the selected first-public key.