WO2018070743A1

WO2018070743A1 - Security device for preventing leakage of data information in solid-state drive

Info

Publication number: WO2018070743A1
Application number: PCT/KR2017/011096
Authority: WO
Inventors: 김동범
Original assignee: 김동범
Priority date: 2016-10-10
Filing date: 2017-10-02
Publication date: 2018-04-19

Abstract

Disclosed is a security device for preventing leakage of data information in a solid-state drive. The present invention provides a security device for preventing leakage of data information in a solid-state drive (SSD) that is used up and discarded, wherein a user can electrically damage and destroy a flash memory directly by himself/herself in order to prevent leakage of data stored in the solid-state drive.

Description

Data State Disclosure Security Device for Solid State Drives

The present invention relates to a data information leakage prevention security device of a solid-state drive, and more particularly, to prevent leakage of data stored in a solid-state drive (SSD) that is disposed of and discarded. It is a data state leakage protection device of a solid-state drive that can directly damage the flash memory and destroy itself.

In order to protect the information of an organization or an individual, a company, a public institution, a military unit, a financial company, an organization, or an individual using a computer, after the use of the computer is completely deleted, deletes the data stored in the storage medium of the computer, and discards or sells it The management and technical aspects of donation, donation, etc. are very important. This is because computers, which are expired in schools, government offices, corporations, financial periods, military units, etc., frequently leak information while being discarded or used.

SSDs include flash memory (NAND flash memory), a non-volatile storage device that retains its stored data even when its power supply is lost. Flash memory has traditionally been used in mobile devices such as digital cameras, mobile phones, PDAs because of its low power consumption and free input and output of information, but in recent years, SSD (Solid), a mass storage device employing the same input / output interface as a hard disk of a computer -State Drive, and it is rapidly replacing hard disk with computer data permanent storage device because of its high processing speed, noise, low heat and low power consumption. As such, there is no system for preventing data information leakage and the destruction of the storage medium when the storage medium is switched to the SSD. On the other hand, there is a concern that information stored in SSDs may be leaked due to the sale of used SSD-equipped information devices. It may be considered to use a degauser, a crusher, or a perforator used in the disposal of a conventional hard disk for disposal after termination of the SSD. However, the degauser is a hard disk dedicated device that destroys only recorded data with a strong magnetic field, not circular destruction, and cannot be used in an SSD. The crusher is used as a dedicated device for hard disks by crushing through circular destruction, and SSD crushing may also be used, but it is inefficient to process a large amount of SSD because it takes about 10 seconds if the processing time is fast. In addition, it is necessary to sort and separate the crushed mixed scraps, which may lead to environmental problems.If rental or separate equipment is required, 100% crushing due to consignment processing is uncertain. You may be exposed to information disclosure risks. The perforator is a dedicated device for hard disks that makes a circular destruction by drilling holes in the hard disk. It is not suitable for drilling flash memory packaged in SSD. Moreover, rental, purchase, and direct operation of these SSD data erasure devices in corporations, public institutions, military units, financial companies, organizations, etc. are inefficient because of the cost and time required. When commissioned to an outside company, the processing status is confirmed through a confirmation letter or report, but it is difficult to guarantee 100% crushing certainty, and it is difficult for a computer user to check whether the data storage area has been processed to such an extent that it cannot be recovered. . Therefore, there is always a risk of information leakage during consignment processing.

As described above, the present invention has been made in order to prevent data information from leaking by erasing data remaining in the flash memory of the SSD after the end of the use of the SSD. The first problem to be solved by the present invention is a device installed in the SSD itself. The goal is to provide data leakage prevention security for solid-state drives that allows users and administrators to select and execute the irreversible destruction of data storage areas of SSD flash memory.

The above object of the present invention is a data storage flash memory, a data interface for data communication with a host, a device controller for controlling a data exchange operation between the flash memory and a host through the data interface, A solid state drive comprising a buffer memory for temporarily storing data read from the flash memory and data to be written to the flash memory, wherein the solid state drive includes the device controller. Apart from this, a high voltage pulse generator is provided to generate and output a control gate dielectric breakdown voltage (high voltage pulse in the DC 60V ~ 240V range) that can destroy the control gate dielectric layer of the flash memory cell when the user operates the switch. The flash memory The memory controller includes a voltage selection circuit for selecting and inserting a high voltage pulse of the high voltage pulse generator in a word line of a flash memory cell array. When the user turns on the switch, the memory controller is configured to display all word lines. And applying the control gate dielectric breakdown voltage to the word lines of the flash memory cell array while sequentially addressing the bit lines.

The high voltage pulse generator is electrically connected to the output side of the power supply of the computer is a DC converter that is boosted by receiving a DC power from the power supply, and is electrically connected to the output side of the DC converter to regulate the output current of the DC converter. A resistor connected to the resistor in series, the relay intermittently intercepting the output current of the resistor, a diode connected in series to the relay, and allowing the current passing through the relay to flow in only one direction; A thyristor configured to be charged with a voltage capable of damaging the memory cell of the flash memory by a current flowing through the diode, and a thyristor connected in parallel with the capacitor to one-way energize the current charged in the capacitor to the wiring; The relay when the user closes the switch, It may be configured to include a pulse voltage controller to close and open a predetermined time to charge the capacitor, and to operate the thyristors while the capacitor is charged to control the high voltage charged in the capacitor to be applied to the wiring.

Preferably, the relay is a contactless relay.

The wiring may further include an energization indicator for displaying the high voltage pulse generator when the high voltage pulse is generated and output to the wiring.

According to the present invention, since the SSD or the computer user or the administrator can directly destroy the memory cells of the SSD through a direct selection and high voltage application operation without the need for a consignment process to an external company, You do not need to rent, purchase or operate your equipment. Therefore, not only the cost and time of SSD storage data discard processing can be saved, but information leakage due to SSD export can be prevented at the source.

1 is a block diagram of a data information leakage prevention security device of a solid state drive according to an embodiment of the present invention.

2 is a circuit diagram of an example of a high voltage pulse generator according to the present invention.

3 is a block diagram illustrating a method of applying the high voltage pulse generator of FIG. 2 to a flash memory.

Hereinafter, specific embodiments of the SSD data information leakage prevention security apparatus according to the present invention with reference to the accompanying drawings will be described in detail.

Memory cells in a typical flash memory store and erase information in a single transistor of a double poly-silicon structure. The memory cell of the dual poly structure is formed in the order of a semiconductor substrate, a tunneling oxide film, a floating gate, a dielectric film, a control gate, a source and drain region, a spacer, and the like. The flash memory has two gates, a floating gate and a control gate. The floating gate and the control gate are separated by a dielectric film, and the floating gate and the silicon substrate are separated by a tunneling oxide film. Data storage in such flash memories is typically implemented by inserting or erasing electrons or holes in the floating gate. That is, since the floating gate is completely isolated by the tunneling oxide layer and the dielectric layer, for example, the nitride-oxide (O) or oxide-nitride-oxide (ONO) dielectric film, the electrons or holes once entered into the floating gate are not supplied with power. Data cannot be lost because it cannot exit the floating gate. On the other hand, for writing or erasing data, a voltage applied to an externally accessible terminal, that is, a control gate, must be induced to the floating gate so that a high electric field can be formed across the tunneling oxide film. The ratio of the voltage applied to the control gate to the floating gate is called a coupling ratio (CR), and the greater the coupling ratio, the greater the program and erase operation efficiency for the memory cell and the lower the voltage that must be applied externally. There is a number. That is, the control gate is an electrode serving as an actual gate among nonvolatile memories having a polysilicon stack structure, and program writing and erasing of the device is performed according to the bias state of the electrode. However, since the dielectric film between the control gate and the floating gate is formed extremely thin for high integration, when the dielectric breakdown voltage that destroys the dielectric film is applied to the control gate, the dielectric film is damaged and the flash memory cell does not function. The flash memory operates a program and erase at a relatively high bias (20V), but since the thickness of the dielectric film is extremely thin, the voltage is more than three times higher than the normal driving voltage (60V or more, which is controlled in the present invention). When the gate breakdown voltage is applied, the dielectric film is destroyed and the flash memory cell no longer functions. Meanwhile, the control gate of the flash memory cell is commonly used with the word line. Applicants have repeated tests to confirm that the dielectric breakdown voltage in the range of 60-240V is applied to the control gate or word line, causing the gate dielectric to break down and the word line to be shorted. The present invention relates to a security device capable of artificially damaging a memory cell of a flash memory by bypassing an overvoltage blocking circuit.

The embodiment shown in FIG. 1 is a data information leakage prevention security device that can be used by detaching the high voltage pulse generator 11 and connecting to the solid state drive only when necessary. The high voltage pulse generator 11 may be integrally formed with the solid state drive.

As shown in FIG. 1, a solid state drive 1 includes a flash memory 3 for data storage, a data interface 31 for data communication with a host, and the data interface. A device controller 7 for controlling a data exchange operation between the flash memory 3 and the host through the 31; data read from the flash memory 3 by the device controller 7 and the flash memory 3; A buffer memory 9 for temporarily storing data to be written to). The device controller 7 is electrically connected to the data interface 31 and the flash memory 3 to control data transmission and reception with an external host (a central processing unit of a computer) and reading / writing of data to the flash memory 3. do. The data interface 31 of the SSD generally uses Serial AT Attachment (SATA) compatible with the hard disk interface.

As shown in FIG. 3, the flash memory 3 includes a flash memory cell array 49 and a memory controller, and the memory controller includes a row decoder (X Address Decoder) 45 for a word line address. And a column decoder (Y Address Decoder) 47 for bit line addresses, memory control logic 41 for generating various control signals, and the like. The row decoder 45 receives a word line address and a word line disable signal from the memory control logic 41 to select a word line. The column decoder 47 receives the bit line address and the bit line disable signal from the memory control logic 41 to select the bit line.

As shown in Figs. 1 and 2, a feature of the present invention is a solid state drive of a flash memory cell when the user operates the switch 27 separately from the device controller 7. A high voltage pulse generator 11 capable of generating and outputting a control gate dielectric breakdown voltage (high voltage pulse in the range of 60 V to 240 V) capable of breaking a control gate dielectric layer is provided, and the memory controller of the flash memory 3 is provided. In the word line of the flash memory cell array 49, a voltage selector 43 for selecting and inputting a high voltage pulse of the high voltage pulse generator 11 is provided.

As shown in FIG. 3, when the user turns on the switch 27, the memory control logic 41 controls the voltage selection circuit 43 to control the high voltage pulse of the high voltage pulse generator 11. Flash memory cell array 49 while allowing an output to be applied to a word line and controlling the row decoder 45 and column decoder 47 to sequentially address all word and bit lines of memory cell array 49. Apply control gate dielectric breakdown voltage to all word lines.

As shown in FIG. 1, the present invention provides a wiring 5 for bypassing the device controller 7 and injecting a high voltage pulse into a cell transistor word line of the flash memory 3. The high voltage pulse generator 11 generates a high voltage pulse of a degree that breaks down the dielectric film of the control gate of the memory cell of the flash memory 3 by switching the user and outputs the high voltage pulse to the wiring. ).

The high voltage pulse at which the control gate of the memory cell of the flash memory 3 breaks down is a voltage in the DC 60V to 240V range. That is, the memory cell of the flash memory 3 is composed of a single transistor, and the word line bias voltage rating of each transistor is less than 60V (usually 15V-20V). Therefore, when a high voltage pulse in the DC 60V ~ 240V range is applied to the word line as a bias voltage, the memory cell breaks down in the control gate dielectric and becomes permanently irrecoverable. This is different from the normal erasing or batch erasing of the memory cell stored data of the flash memory by the control gate bias voltage control.

As shown in FIG. 1, the wiring 5 further includes an electricity supply indicator 39, such as an LED, which indicates when the high voltage pulse generator 11 generates a high voltage pulse and outputs the same to the wiring.

As shown in FIG. 1, only the wiring 5 is formed in the SSD 1 in advance, and the high voltage pulse generator 11 is manufactured separately, and then the connector 37 and the wires connected to the high voltage pulse generator 11 are connected. It may be removable to the SSD 1 by using a socket 35 connected to 5). The high voltage pulse generator 11 and the wiring 5 may be manufactured integrally with the SSD 1. In Fig. 1, reference numeral 33 denotes a SATA power supply terminal.

As shown in FIG. 3, the high voltage pulse generator 11 is electrically connected to an output side of a power supply 13 of a computer (or host side) to receive and boost DC power from the power supply 13. A DC converter 15, a resistor 29 electrically connected to an output side of the DC converter 15 to regulate an output current of the DC converter 15, and connected in series with the resistor 29; A relay 17 intermittently intercepting the output current of (29), a diode (19) connected in series with the relay (17) to allow the current passing through the relay (17) to flow in only one direction, and the diode (19) And a capacitor 23 connected in series with the capacitor 19 and charged in a voltage capable of damaging the memory cell of the flash memory 3 by a current flowing through the diode 19. Charging in the condenser 23 Thyristor 21 for energizing the current to the wiring 5 in one direction, and when the user closes the switch 27, the relay 17 is closed and opened for a predetermined time to charge the capacitor 23, and the capacitor 23 And a pulse voltage controller 25 for operating the thyristor 21 in the charged state to control the high voltage charged in the capacitor 23 to be applied to the wiring 5. The relay 17 is preferably a contactless relay (SSR).

As shown in FIG. 3, according to the present invention having the above-described configuration, a computer user or an administrator operates the high voltage pulse generator 11 by a switch 27 while the SSD is installed in a computer, thereby operating the memory cell of the SSD. By applying a high voltage pulse to the memory cell, the memory cell of the flash memory can be irreparably destroyed, so there is no need for outsourcing to an external company and no need to rent or purchase and operate a separate device. Therefore, not only the cost and time of SSD storage data discard processing can be saved, but information leakage due to SSD export can be prevented at the source.

Claims

A flash memory for data storage, a data interface for data communication with a host, a device controller for controlling data exchange operations between the flash memory and the host through the data interface, and the device controller reads from the flash memory. In a solid state drive consisting of a buffer memory for temporarily storing the exported data and the data to be written to the flash memory,

In addition to the device controller, the solid state drive has a control gate dielectric breakdown voltage (high voltage pulse in the DC 60V to 240V range) that can destroy the control gate dielectric of the flash memory cell when the user operates the switch. A high voltage pulse generator capable of generating and outputting a voltage selector for selecting and inputting a high voltage pulse of the high voltage pulse generator to a word line of a flash memory cell array in a memory controller of the flash memory; When the user turns on the switch, the memory controller applies the control gate dielectric breakdown voltage to the word lines of the flash memory cell array while sequentially addressing all word lines and bit lines. Data definitions on solid state drives Leak Prevention security.
The method of claim 1,

The high-voltage pulse generator is electrically connected to the output side of the power supply of the computer and the direct current converter is boosted by receiving the DC power from the power supply, and is electrically connected to the output side of the DC converter to regulate the output current of the DC converter. A resistor connected to the resistor in series with the resistor to interrupt the output current of the resistor; a diode connected to the relay in series so that the current passing through the relay flows in only one direction; A capacitor charged with a voltage capable of damaging the memory cell of the flash memory by a current flowing through the diode, a thyristor connected in parallel with the capacitor to energize the current in the capacitor in one direction; When the user closes the switch, the relay Prevents leakage of data information of the solid state drive including a pulse voltage controller which charges the capacitor and closes and opens it for a predetermined time and operates the thyristor while the capacitor is charged so that a high voltage charged in the capacitor is applied to the wiring. Security device.
The method of claim 1,

The wiring apparatus further includes a current-carrying indicator for indicating when the high voltage pulse generator generates a high voltage pulse and outputs the wiring to the data information leakage prevention security device of the solid state drive.