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

Claim 15:
16. A public-key encryption method comprising:
establishing communication with a private-key decryption device;
obtaining a first public-key matrix, wherein the first public-key matrix is associated with the private-key decryption device;
obtaining a key size for the transmission key;
generating a transmission key according to the key size;
determining a matrix size for the second private-key matrix, wherein the matrix size is arranged to accommodate masking of the transmission key;
generating a second private-key matrix according to the matrix size;
computing 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;
computing a second raw shared key from the second private-key matrix and the first public-key matrix;
computing the second raw shared key, wherein the second raw shared key comprises a matrix multiplication between the second private-key matrix and the first public-key matrix;
masking the transmission key with at least part of the second raw shared key; and
transferring 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; and
performing a handshake with the private-key decryption device, wherein the handshaking comprises:
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.