News Column

Patent Issued for Secure External Buffer for Hard Disk Drive System on a Chip

July 29, 2014

By a News Reporter-Staff News Editor at Information Technology Newsweekly -- STMicroelectronics, Inc. (Coppell, TX) has been issued patent number 8782430, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Furness, Duncan (Boulder, CO); Brianti, Francesco (San Jose, CA); Tamagno, David (Boulder, CO).

This patent was filed on January 22, 2010 and was published online on July 15, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Embodiments of the present invention relate, in general, to secure data transfer to hard disk drives using a System on a Chip (SoC) and more particularly to securing data on an external buffer associated with a SoC using an eXclusive Or (XOR) encryption methodology.

"Host devices such as computers, laptops, personal digital assistants, MP3 players, game consoles, set top boxes, digital cameras and other electronic devices often need to store and access large amounts of data. Storage devices such as hard disk drives (HDD) are often used to meet the data storage needs of such devices. The transfer and storage of data dates back to the origination of the computer. Where and how do you store the programs, data and calculations? Over the years the answers to those questions have resulted in faster and more capacious methods of mass storage. There are numerous concepts to consider in the transfer and storage of data. These include access time, data transfer rate, formatting, compression and more. Many of these questions with respect to data storage and transfer have been resolved on a single chip referred to as a SoC. With respect to data storage, a SoC takes data from a host such as a computer and delivers it to a storage media such as a hard disk drive. One issue to address in the storage of data is that the production of data from a host is rarely continuous or consistent. It would be inefficient to convey data to a storage medium as it arrives from the host. Thus one function of a SoC is to collect data until it is ready to be stored. This collection occurs in a buffer.

"FIG. 1 shows an exemplary version of a HDD SoC as would be known to one skilled in the relevant art. The HDD SoC 112 is interposed between a host 146 and a hard disk assembly (HDA) 113. The HDA 113 in this rendition includes a disk platter 114 that is coated with magnetic material 115 and which revolves around and is driven by a spindle motor 116. Generally the spindle motor 116 rotates the platter 114 at a fixed speed during read/write operations as an actuator 118 moves a read/write device 120 over the platter 114 to read/write the data.

"The read/write device 120 is located at the distal end of the actuator arm 118 and includes a write element such as an inductor that can generate a magnetic field as well as a read element such as a magnetic-resistive element that can sense a magnetic field present on the platter 114. A preamp circuit 122 amplifies the low level signals from the read element and outputs the data to a read channel 124 located on the HDD SoC 112.

"When data is written to the platter 114 a current is generated so as to flow to the read/write device 120. The current is switched, forming a magnetic field which is adopted by the platter 114 and represents data.

"The HDD SoC 112 typically includes a buffer 132 linked to the hard disk controller 136. The buffer 132 of the HDD SoC 112 and/or other external memory resources can be (as illustrated in FIG. 1) external to the SoC 112 and linked to the HDC 136 to increase capacity. The buffer 132 stores data associated with the control of the hard disk drive and/or buffers data to allow data to be collected and transmitted as larger blocks so as to improve efficiency. Data stored on an external memory resource must be secure, i.e. external data resources cannot possess data stored in the clear. As is well known to one skilled in the relevant art, data stored on external buffers 132 are generally encrypted using an encryption engine 135.

"As one skilled in the art will appreciate, many robust encryption techniques can be used to secure data. The HDD SoC 112 also includes a processor 134 that performs any necessary processing related to the operation of the HDD including that of the hard disk controller 136 and encryption component 135. The hard disk controller 136 communicates with the host device 146 via a HDD interface 136 and the host interface 144.

"This encryption engine is generally associated with the host device 146 meaning that upon every read or write command issued by the host 146, the data is first processed by the encryption engine prior to being placed on the buffer 132. Thereafter the data is collected and eventually transferred to the storage device. Data being retrieved from the HDA 113 is collected on the buffer and thereafter decrypted by the encryption engine before transfer to the host. This interaction amongst the host 146, buffer 132 and storage media (client) adds complexity to the HDD SoC 112. In one example an external buffer 132 with a host side encryption scheme has been shown to add 1.4 Mega Gates (MG) to a typical SoC to ensure that data kept on an external buffer remains secure.

"One encryption scheme used in this example is a Feistel network-based cipher designed for use with digital data. The cipher is very robust and efficient when implemented in software or, when small, when implemented in hardware. The two primary components of a cipher are the cipher itself (usually positioned on the host) and media key blocks comprising cryptographic values that implement broadcast key distribution and provide renewability in content protection solutions. However the robustness of the cipher increases the complexity of the SoC architecture. Indeed while data housed external to the SoC must be secure, a robust cipher needlessly adds excess complexity to the SoC without providing compensatory security advantages.

"A system and associated methodology for securely interfacing with an external memory buffer from a SoC without the added complexity of current encryption techniques is therefore desirable. These and other improvements of the prior art are addressed by one or more embodiments of the present invention as described hereafter by way of example."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "A system for securely buffering hard disk drive data using a host side XOR encryption engine is hereafter described by way of example. According to one embodiment of the present invention, a host communicates with an encryption interface interposed between the host and a client. Communicatively coupled to the encryption interface is an external buffer for the collection and processing of data. According to one embodiment of the present invention, a host side XOR encryption engine, using a random seed, encrypts data originating from the host and places it on the external buffer. Once collected at the buffer and ready for transmittal to the client, the encrypted data is retrieved by the encryption interface and decrypted. The clear data is then encrypted using a robust encryption means such as Advance Encryption Standard encryption for conveyance to the client.

"The features and advantages described in this disclosure and in the following detailed description are not all-inclusive. Many additional features and advantages will be apparent to one of ordinary skill in the relevant art in view of the drawings, specification, and claims hereof. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes and may not have been selected to delineate or circumscribe the inventive subject matter; reference to the claims is necessary to determine such inventive subject matter."

For the URL and additional information on this patent, see: Furness, Duncan; Brianti, Francesco; Tamagno, David. Secure External Buffer for Hard Disk Drive System on a Chip. U.S. Patent Number 8782430, filed January 22, 2010, and published online on July 15, 2014. Patent URL:

Keywords for this news article include: Information Technology, Information and Data Encoding and Encryption, Information and Data Storage, STMicroelectronics, STMicroelectronics Inc.

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Source: Information Technology Newsweekly

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