Stmicroelectronics Gmbh

Stmicroelectronics (research & Development) Limited

Stmicroelectronics R&d Limited

Peter Bennett

Andrew R Dellow

Paul Elliott

Rodrigo Cordero

Andrew Dello

Jonathan Smailes

Paul Elliot

A semiconductor integrated circuit for the processing of conditional access television signals that includes an input interface for receiving encrypted television signals and an output interface for output of decrypted television signals. The semiconductor integrated circuit is provided with some functionality restricted in some way by preventing one or more hardware circuit elements from operating, such as an MPEG decoder, display engine, IO ports or main CPU. To enable the functionality, a subscriber must pay for a service and then receives an encrypted message broadcast to the semiconductor integrated circuit that is decrypted and instructs functionality to be turned on or off.

Method of providing an audio-video device to an end user

Security integrated circuit

A filter is arranged to selectively block or allow a data access command from an initiator according to whether the initiator is secure or insecure and whether a data source or destination being accessed is privileged or unprivileged. The data access command contains an identification of the initiator from which the data access command originated and an identification of the data source or destination being accessed. The security filter compares the initiator identification and data source or destination identification contained within the data access command with a list of those initiators defined as secure and a list of those data sources or destinations which are defined as unprivileged. The filter then blocks or allows the data access command signal according to a set of rules.

System for restricting data access

A memory stores data in an encrypted form. A modifiable register stores a memory address, a, defining a boundary separating the memory into two regions. The lower region stores data encrypted using a key B, and the upper region stores data encrypted using a different key A. Data stored on the boundary address is encrypted using key A. Accordingly, when data is read from a memory address a, key A is used to decrypt the data if a&#x2267;a, and key B is used if a&#x3c;a. However, when data is written to a memory address a, then key A is used to encrypt the data if a&#x2267;a+1, key B is used if a&#x3c;a+1. When data is written to the boundary address, a, the position of the boundary is caused to increase by one unit.

Key update mechanism

An integrated circuit restricts use of a data item and includes a data memory storing the data item; a value memory storing a value; a signature input that receives a signature derived from data in a data item field and a value in a value field, the signature being in a coded form; a decoding circuit that decodes the signature and outputs information representing the data in the data item field and the value in the value field; and a comparison circuit that receives the decoding circuit output, determines whether the information representing the data from the data item field corresponds to the stored data item and whether the information representing the value from the value field corresponds to the value stored in the value memory, and outputs a comparison signal according to the determinations. The circuit restricts the use of the data item according to the comparison signal.

Method and system for restricting use of data in a circuit

A semiconductor integrated circuit includes a processor for executing application code from a memory and a verifier processor arranged to receive the application code via the same internal bus as the processor. The verifier processor performs a verification function to check that the application code is authentic. The verifier processor runs autonomously and cannot be spoofed as it receives the application code via the same internal bus as the main processor. An additional instruction monitor checks the code instructions from the CPU and also impairs the operation of the circuit unless the address of code requested is in a given range. The code is in the form of a linked list and the range is derived as a linked list table during a first check.

Memory security device for flexible software environment

A memory access system including a memory in which data is organized in pages, each page holding a sequence of data elements; means for receiving a requested address including a requested page address and a requested data element address; logic for accessing a current page from the memory using a current page address; logic for reading out data elements of the current page in the sequence in which they are held in memory; logic for comparing the requested page address with the current page address and for issuing a memory access request with the requested page address when they are not the same; and logic operable when the requested page address is the same as the current page address for comparing a requested data element address with the current address of a data element being read out and returning the data element when the requested data element address matches the current data element address.

Memory access

Retiming circuitry for retiming a data signal transmitted from a first environment under control of a first clock signal to a second environment under control of a second clock signal, said first and second clock signals having a known repeat relationship, the retiming circuitry comprising a plurality of delay elements for delaying said data signal; a plurality of inputs connected to said delay elements for receiving said data signal at respectfully different delays; selection means for selecting the data signal at one of said inputs based on said known repeat relationship; and an output for outputting said selected data signal.

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Bristol, United Kingdom

Peter Bennett