US 12,438,697 B2
Communication system, information processing apparatus, communication method and program
Keizo Murakami, Tokyo (JP); Yuki Okano, Tokyo (JP); and Tetsutaro Kobayashi, Tokyo (JP)
Assigned to NTT, Inc., Tokyo (JP)
Appl. No. 18/260,113
Filed by NTT, Inc., Tokyo (JP)
PCT Filed Jan. 14, 2021, PCT No. PCT/JP2021/001111
§ 371(c)(1), (2) Date Jun. 30, 2023,
PCT Pub. No. WO2022/153455, PCT Pub. Date Jul. 21, 2022.
Prior Publication US 2024/0056288 A1, Feb. 15, 2024
Int. Cl. H04L 29/06 (2006.01); H04L 9/06 (2006.01); H04N 7/15 (2006.01)
CPC H04L 9/0618 (2013.01) [H04N 7/15 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A communication system comprising:
an information processing device that provides a video conference service; and
a plurality of communication terminals using the video conference service, said communication terminals being configured to generate communication data, encrypt the communication data and transmit the communication data to the information processing device,
wherein the information processing device includes:
a memory; and
a first processor configured to execute
recording the communication data related to a video conference encrypted and transmitted from each of the communication terminals in a first storage for each of the communication terminals;
transmitting, to the communication terminals, a ciphertext obtained by encrypting an encryption key capable of decoding each item of the communication data recorded in the first storage such that the encryption key can be decoded by the communication terminals; and
transmitting the communication data recorded in the first storage to the communication terminals, and
the communication terminals each include:
a memory; and
a second processor configured to execute
decoding the communication data for each of the communication terminals using a decoding result of the ciphertext; and
reproducing video and audio included in the communication data decoded for each of the communication terminals in synchronization with each other on a basis of control data included in each of the communication data,
the second processor is configured to execute synchronized reproduction of the video and audio by adjusting a reproduction start timing of the video and audio and a display position of screen sharing information, based on control metadata included in the communication data of each of the communication terminals, the control metadata including time data and a display position on a screen,
wherein the first processor further executes:
when receiving a public key generated by any of the communication terminals from said any one of the communication terminals, recording the public key in a second storage;
receiving, from any of the communication terminals, the ciphertext of the encryption key encrypted using all the public key recorded in the second storage in the video conference; and
converting the ciphertext such that the ciphertext can be decoded using a secret key for the public key of any of the communication terminals in response to a request from said any of the communication terminals, and
transmitting the ciphertext after conversion to said any of the communication terminals.