Data decryption circuit and method

Abstract

The present invention discloses a data decryption circuit and method for decrypting a currently encrypted data package, the currently encrypted data package includes a header data and a bearer data. The data decryption circuit includes: an operation unit for generating a first data according to the header data and a virtual random number, generating a second data according to a session key and a constant, and generating the first data according to the header data Carrying a length information and a starting position information of the data; wherein, the computing unit generates the first data, the second data, the length information and the starting position information by executing the program code; and a decryption calculation circuit, coupled to the computing unit, used to generate a decryption key according to the first data and the second data, and obtain the bearer data from the currently encrypted data packet according to the initial position information and the length information, and use the The decryption key decrypts the bearer data.

Description

technical field [0001] The present invention relates to a data decryption circuit and method, in particular to a data decryption circuit and method utilizing software and hardware to cooperate with each other. Background technique [0002] see figure 1 , which is a schematic diagram of a conventional data decryption process of High-Bandwidth Digital Content Protection (HDCP for short). Please also see figure 2 , which is a conventional composition diagram of a transport stream (TS) packet. like figure 2 As shown, a transport stream packet 200 includes TS header data, elementary packet stream (packetized elementary streams (PES) header data, and elementary stream (elementary stream, ES), or called payload. In the HDCP standard, the TS header data includes a flag named payload unit start indicator, which is used to indicate whether the transport stream packet contains PES header data. The PES header data includes private data for decryption, and the private data mainly ...

AI Technical Summary

Problems solved by technology

[0004] if figure 1 The shown HDCP decryption program is completely executed by hardware. Due to the lack of flexibility of the hardware, the above-mentioned action of combining two bearer data originally belonging to different transport stream packets will cause difficulties in hardware design, and additional circuit design is necessary to cope with different Therefore, it is easy to cause time-consuming design and increased circuit cost; and if the HDCP decryption program is completely executed by software, that is, executed by the processing unit (processing unit) through program code, the HDCP decryption program will take up a lot of time. The resources of the computing unit, causing the burden of the computing unit, may drag down the performance of electronic devices

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