Arm Limited

Mstar Semiconductor, Inc.

Mstar France Sas

Mstar Software R&d (Shenzhen) Ltd.

Secure Thingz Limited

John David Mersh

A data processing apparatus formed on an integrated circuit comprising: a plurality of processors; power control circuitry configured to control power up and power down of the processors; a read only memory for storing boot up software for booting up each of the processors. The power control circuitry is configured to respond to receipt of a check state request, to control one of the processors that is currently powered down to power up and to access the boot up software. The boot up software accessed in response to the check state request controls the processor to perform a measurement indicative of a current state of the data processing apparatus and to output a value indicative of the measurement.

Providing a trustworthy indication of the current state of a multi-processor data processing apparatus

A data processing device with a processor, a memory and an access control mechanism, the device having secure and non-secure modes, the memory having secure and non-secure regions, the secure region containing cryptographic data, and the access control mechanism preventing the processor from reading the cryptographic data when the device is operating in the non-secure mode. Also, methods of manufacturing and authenticating such a device, manufacturing an item of electronic equipment that includes such a device, a computer program for storing data on such a device, secure data processing hardware including such a computer program and a method of updating data stored in an item of electronic equipment including such a data processing device.

Data processing device

A method comprising encrypting an original plain text file and making it available to a user as a protected file, and issuing to said user a user program and a user license to enable said user to decrypt the protected file and view an image of the original file while preventing the image of the original file from being copied to any file, other than as a further protected file. The image is preferably stored in a memory not backed up to the computer swap file. Preferably, the user program comprises an editor program and the user saves editorial changes to the original image in an encrypted difference file, separate from the original file. Both files are then used to re-create the edited image using the editor program and user license. The user program may comprise any computer tool including compilers. Alternatively, the user program comprises a special editor program incorporating an obfuscator which generates obfuscated code from the image generated by the editor program, so that this is only intelligible to a compiler or similar tool capable of converting the obfuscated code to an object file.

Source code protection

A method of maintaining the integrity of software stored in memory, the method comprising: storing an indicator associated with the memory; calculating a reference value from the stored indicator; storing the reference value; modifying the indicator when the software in the memory is modified; storing the modified indicator; recalculating the reference value from the modified indicator; storing the recalculated reference value; and verifying the integrity of the software by: retrieving the modified indicator; calculating an expected value from the modified indicator; and comparing the expected value with the recalculated reference value. Preferably the integrity of the software is verified without calculating an expected value from the software. The reference and expected values are typically calculated in accordance with a secret key.

Growing community of inventors

Bottisham, United Kingdom

John David Mersh