Samsung Electronics Co., Ltd.

Hak-soo Ju

Myung-Sun Kim

Ji-young Moon

Young-sun Yoon

Choong-Hoon Lee

Sun-nam Lee

Ju-hee Seo

Mi-Hwa Park

Jin-Mok Kim

A method and apparatus for managing digital content are provided. The apparatus for managing digital content generated by applying digital rights management (DRM) includes: a content execution unit executing digital content; and a control unit confirming whether or not digital content is in a first period in which the digital content can be normally executed, and controlling the content execution unit so that, if the digital content is in the first period, the digital content can be executed normally, and if the digital content is in a second period which is not in the first period, the digital content can be executed in a manner which can be distinguished from that of execution in the first period. According to the apparatus and method, execution of digital content, which is close to expiration, can be controlled, thereby managing the expiration of the digital content for a user.

Method and apparatus for managing digital content

A reproduction method capable of immediately revoking a leaked device key by dividing the device key into a first partial key and a second partial key is provided. The reproduction method includes the operations of receiving encrypted content to be reproduced, requesting a token for decrypting the received content from an external device containing a first partial key of a device via a network, receiving the requested token from the external device, and decrypting the received token by using a second partial key contained in the device, thereby preventing content encrypted and distributed before revocation of an illegally copied device from being reproduced, and minimizing damage due to key leakage.

Method and devices for reproducing encrypted content and approving reproduction

Provided are a method of tracing a device key in a user key management system using a hierarchical hash chain broadcast encryption scheme (HBES) algorithm, a user key management system for executing the method of tracing a device key, and a computer program for executing the method of tracing a device key. The method of tracing a device key of an illegal decoder in a user key management system for broadcast encryption includes: tracing a device key using a binary search; and revoking the traced device key. The technology according to the present invention can be applied to prevent exposure of the device keys to hacking. The present invention provides a method of tracing which can be applied to an HBES algorithm structure.

Method of tracing device keys for broadcast encryption

Growing community of inventors

Suwon-si, South Korea

Hak-soo Ju