KR20110023685A - Solid state disk with authentication function and driving method thereof - Google Patents

Abstract

PURPOSE: A SSD(Solid State Disk) with an authentication function and an operating method thereof are provided to prevent date modification by a user who does not have proper authority by performing data reading/writing/deleting about a flash memory after checking a user who has proper authority through authentication through PIN(Personal Identification Number) or a fingerprint sensor. CONSTITUTION: A connector unit(330) is connected to a computer and performs data transceiving. A flash memory(310-1~310-n) store the data. A memory controller(320) controls the flash memory. If an initial connection signal with a computer is sensed through a connector unit, a controlling unit(340) deactivates the memory controller and performs user authentication. If a user authentication is succeeded, the control unit activates the memory controller.

Description

SD with authentication function and driving method thereof {Solid State Disk with authentication function and driving method

The present invention relates to a solid state disk (SSD) having an authentication function and a method of driving the same, and more particularly, after confirming that the user has a legitimate authority through PIN (Personal Identification Number) authentication or authentication through a fingerprint sensor. The present invention relates to an SSD in the form of a Peripheral Component Interconnect Express (PCI-Express) card that performs data read / write / erase on a flash memory and a method of driving the same.

Recently, social awareness on information security has been gradually improved, and the demand for a means for this is increasing rapidly. For example, damages are increasing due to numerous hacking techniques such as phishing and back doors on the Internet, and they are exposed to situations where information can be leaked anywhere anytime due to poor information management of individuals or companies. have. In addition, a personal computer (PC) may be subject to information invasion due to hacking while physically connected to the Internet, and a storage device built into the PC may be leaked to the outside due to theft. In particular, the leakage of confidential data of the company is, in the least, damage to individuals or companies, and largely to national losses. Therefore, there is a need for a fundamental countermeasure that can fundamentally maintain security of important confidential data, source codes, and design drawings stored in personal PCs in corporations and public institutions.

Ideally, physically separating data from the network (eg, the Internet) will maintain the highest level of security, but carrying the PC itself is a difficult task for the user and diminishes resource utilization. In addition, laptops are less efficient due to their relatively low performance. High-performance laptops are vulnerable to high price and mobility.

Therefore, in order to solve such a problem, a method of providing mobility to a storage device, which is the core of security, has been used. Accordingly, some relatively high capacity storage devices have been developed. However, until now, the hard disk (hard disk) most widely used as a storage device is physically vulnerable and relatively large in volume, which has many limitations in mobility. Although such an attempt has been made through USB memory, low performance (eg Because of this, the performance was very slow.

On the other hand, SSD (Solid State Disk) has recently been in the spotlight as a next-generation storage device to replace a removable hard disk or USB, SSD is connected to a plurality of flash memory in parallel and each flash memory using a high-performance controller The ability to access all of them at the same time has the advantage of superior performance over other flash memory based storage devices. In the case of hard disks, since they are mechanical devices (for example, platters, heads, motors, etc.), they have a limited volume and appearance, whereas SSDs using nonvolatile flash memory have a form factor. It also has the advantage of being free. In addition, SSD does not damage data due to external shock, heat, noise and power consumption is low, and has the advantages of miniaturization and light weight.

In this regard, Figure 1 illustrates a configuration of a solid state disk (SSD) according to the prior art.

Referring to FIG. 1, the SSD according to the related art is composed of a plurality of flash memories 110-1,..., 110-n, a memory controller 120, and a Peripheral Component Interconnect Express (PCI-Express) interface 130. The memory controller 120 controls the plurality of flash memories 110-1,..., 110-n to output data input from the outside (eg, a computer) through the PCI-Express interface 130. -1, ..., 110-n), and outputs the data to the outside (eg, a computer) through the PCI-Express interface 130 when there is a request for the stored data.

However, the SSD according to the related art is superior to a conventional removable hard disk or a USB memory in terms of mobility, storage capacity, operating speed, etc., but as previously mentioned, a conventional storage medium (for example, a removable hard disk) is secured. , USB memory, etc., the same level of security is still available, for example, if an employee or industrial espionage, such as a company or a public agency, attempts to steal company secrets maliciously, or loses an SSD that contains sensitive data. There was a problem that revealed the limitations.

The present invention was devised to solve the above-described problems, and an object of the present invention is to confirm that the user has a right authority through a PIN (Personal Identification Number) authentication or authentication through a fingerprint sensor, and then the data for the flash memory. An SSD having an authentication function for performing read / write / erase and a driving method thereof are provided.

Another object of the present invention is to voluntarily delete data stored in the flash memory when a user without proper authority fails authentication several times, thereby providing an authentication function to prevent information leakage to the outside even if theft or loss occurs. It is to provide an SSD and a driving method thereof.

Still another object of the present invention is to provide an SSD having an authentication function for booting a corresponding computer using an operating system (OS) program stored in a flash memory when a boot signal of the computer is detected, and a driving method thereof.

Still another object of the present invention is to remove internal storage media (e.g., hard disk) from a computer that is used privately or publicly by a company or a public institution, and to insert and use an SSD in which an OS program according to the present invention is embedded. The present invention provides an SSD having an authentication function capable of protecting a user's information and using the same as a public computer and a driving method thereof.

Still another object of the present invention is to provide an RFID tag inside or outside of an SSD so that the SSD detects when the SSD leaves a predetermined area and prevents leakage of information to the outside. To provide a way.

For this purpose, a solid state disk (SSD) having an authentication function of one embodiment of the present invention includes a connector unit connected to a computer to perform data transmission and reception; At least one flash memory storing data transmitted and received with the computer; A memory controller controlling the at least one flash memory; And upon detecting an initial connection signal with the computer through the connector unit, deactivates the memory controller, authenticates the user using at least one authentication method, and then authenticates the user successfully. And a controller for activating the memory controller.

In addition, an SSD having an authentication function according to another aspect of the present invention includes a connector unit connected to a computer to perform data transmission and reception; At least one flash memory storing a computer operating system (OS) program; A memory controller controlling the at least one flash memory; And upon detecting a boot signal from the computer through the connector unit, transmits an interrupt signal requesting the boot stop to the computer, authenticates the user using at least one authentication method, and then authenticates the user. And a control unit for transmitting the OS program stored in the at least one flash memory to the computer when the program succeeds.

On the other hand, in one embodiment of the present invention, a method for driving an SSD having an authentication function includes: a) inactivating a memory controller upon detecting an initial connection signal with a computer; b) performing authentication for the user using at least one authentication scheme; And c) activating the memory controller when authentication of the user is successful.

In addition, a method of driving an SSD having an authentication function according to another aspect of the present invention may include: a) transmitting an interrupt signal requesting a boot stop to the computer when detecting a boot signal from the computer; b) performing authentication for the user using at least one authentication scheme; And c) if an authentication of the user is successful, transmitting an OS (Operating System) program stored in at least one flash memory to the computer.

According to the present invention, after confirming that the user has a legitimate authority through a PIN (Personal Identification Number) authentication or a fingerprint sensor, the user who does not have the legitimate authority by performing data read / write / erase on the flash memory It has the effect of preventing to change or delete the data stored in.

In addition, according to the present invention, if a user without proper authority fails authentication several times, by spontaneously deleting data stored in the flash memory, information leakage to the outside may be prevented even if theft or loss occurs. .

In addition, according to the present invention, when the boot signal of the computer is detected by booting the computer with an operating system (Operating System) program stored in the flash memory, any computer can have an effect that can be set to suit their computing environment.

In addition, according to the present invention, a public computer (that is, a computer which does not store any information therein and does not leave any information after use) is disposed and has no personal storage medium (for example, a hard disk) in an enterprise or public institution. By inserting and using the SSD embedded in the OS program according to the present invention, it is possible to significantly reduce the number of computers paid for each individual in the company or public institution (this is particularly advantageous in companies with a lot of mobile work), and also built-in Since no hard disk is provided, the cost of purchasing a computer can be reduced, and at the same time, the personal information can be efficiently protected.

In addition, according to the present invention, not only the authentication at the time of booting the computer, but also when accessing a file or data that is specially locked while the OS is running, it can be used as an authentication means.

In addition, according to the present invention, the RFID tag is provided inside or outside the SSD to detect when the SSD leaves a predetermined area, thereby preventing the confidential information of a company, a research institute, a public institution, etc. from being leaked to the outside in advance. Has the effect.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments. For reference, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted in the following description.

First, FIG. 2 is a diagram illustrating an external appearance of an SSD having an authentication function according to an embodiment of the present invention. For reference, the SSD of Figure 2 illustrates an SSD in the form of a PCI-Express card, as shown, the SSD according to an embodiment of the present invention is a PCI-Express slot (slot) provided in the main board of the computer, etc. Insert the PCI-Express interface, the fingerprint sensor to recognize the user's fingerprint, and the status light LED (Light Emitting Diode) to indicate the operating status of the SSD (e.g., fingerprint recognition, data read / write / erase, etc.) Include.

3 is a diagram illustrating a configuration of an SSD having an authentication function according to an embodiment of the present invention.

As shown in FIG. 3, an SSD having an authentication function according to an embodiment of the present invention may include at least one flash memory 310-1,..., 310-n, a memory controller 320, and a connector unit 330. ), The controller 340, the power switching unit 350, the fingerprint recognition unit 360, the status display unit 370, the RFID tag 380, and the like.

First, at least one flash memory 310-1,..., 310-n is a storage medium for storing data, and may be implemented in a structure in which NAND flash memories are connected in parallel. For reference, FIG. 3 illustrates a structure in which n flash memories 310-1,..., 310-n are connected in parallel. The flash memory can be classified into a single level cell (SLC) memory that stores one data in one cell and a multi level cell (MLC) memory that stores two or more data in one cell according to a storage method. However, in the case of the present invention, it is more preferable to implement using MLC memory which is relatively inexpensive rather than SLC memory. In this case, the speed problem due to the limitation of the write / erase is determined by the number of channels accessed by the memory controller 320 at the same time. Solve it by raising it.

The memory controller 320 controls the at least one flash memory 310-1,..., 310-n to write / read / erase data. In detail, the memory controller 320 stores data input from an external device (such as a computer) through the connector unit 330 in at least one flash memory 310-1,..., 310-n, and in this case, If the size is large, the data is fragmented into a plurality of data and distributed in a plurality of flash memories. When there is a request for specific data from the outside (computer, etc.), the memory controller 320 retrieves the data and provides the data. In this case, if the data is distributed and stored in a plurality of flash memories, the data is stored as one data. Provide in combination.

The connector unit 330 is an interface connected to an external computer and the like to perform data transmission and reception. According to a preferred embodiment of the present invention, the connector unit 330 is implemented as a PCI-Express interface or a mini-PCI-Express interface. Accordingly, the SSD according to the present invention may be manufactured in the form of a PCI-Express card.

The controller 340 controls the memory controller 320, the power switching unit 350, the fingerprint recognition unit 360, the status display unit 370, and the like to control the overall operation of the SSD according to the present invention. For example, the controller may be implemented as a micro controller unit (MCU).

For example, if the SSD according to the present invention is connected to the computer while the external computer is booted, the controller 340 detects the first connection signal transmitted from the computer through the connector unit 330 and the memory controller. Deactivate the 320 and perform authentication for the user using at least one authentication method (eg, PIN authentication method, authentication method through fingerprint recognition), and if authentication for the user succeeds in memory The controller 320 is activated.

If the SSD is connected to the computer according to the present invention before the external computer is booted (eg, before the computer is turned on) or during booting, the controller 340 is connected to the computer through the connector 330. Detects a boot signal transmitted, transmits an interrupt signal requesting boot interruption to the computer, authenticates a user using at least one authentication method, and then, if authentication of the user is successful, at least one The OS program stored in the flash memories 310-1,..., 310-n is transferred to the computer. Accordingly, the external computer is driven by the OS program stored in the SSD of the present invention rather than driven by the OS program stored in the hard disk provided therein, so that the user can implement his or her computing environment anytime and anywhere regardless of the computer. . As mentioned above, by using the SSD according to the present invention, it is possible to use a computer without any internal storage medium (eg, a hard disk), so that no information is stored in the computer and no information is stored even after use. Since there is no remaining, it is possible to obtain a very excellent effect in terms of information security, with no fear of information leakage.

In fact, the present invention ultimately provides a minimal number of embedded motherboards including a central processing unit (CPU), a graphics chip, a random access memory (RAM), a PCI-Express slot, and the like in an enterprise or a public institution. Instead of buying a public computer (which doesn't have a hard disk) and having employees use their computers on their desks instead of using it on their own desks, employees can bring these public computers, if needed, to their own solid state disks (SSDs). By plugging into a PCI-Express slot, users can implement their computing environment anytime, anywhere, and eliminate the possibility of information leakage by taking the SSD out of its slot after use.

This is especially important in the case of a company that has a lot of work outside, so it is not necessary to purchase all the computers corresponding to the number of employees, which can drastically reduce the number of computers. In addition, the computer is relatively inexpensive because it does not have an internal hard disk. The cost of purchasing can be reduced twice. In addition, as the public computer is widely used, an individual can obtain the effect of carrying his computer by carrying only his SSD.

Meanwhile, some of the main operations of the control unit 340 have been described above, but other main operations and additional functions of the control unit 340 will be described in detail in related elements or in the method of driving the SSD according to the present invention. Let's do it.

Referring again to FIG. 3, the power switching unit 350 is connected between the connector unit 330 and the memory controller 320, and from the connector unit 330 to the memory controller 320 under the control of the controller 340. It performs a switching function to cut off or supply the supplied power. In detail, when the controller 340 detects the first connection signal transmitted from the computer, the controller 340 transmits an inactive signal to the memory controller 320 to the power switch 350, and the power switch 350 performs such an operation. When receiving an inactive signal, the connector unit 330 cuts off the power provided to the memory controller 320. When the user authentication succeeds and the control unit 340 transmits an active signal for the memory controller 320 to the power switching unit 350, the power switching unit 350 responds to the active signal. Correspondingly, power is supplied from the connector unit 330 to the memory controller 320. For reference, the power switching unit 350 may be implemented as, for example, a relay.

The fingerprint recognition unit 360 includes a fingerprint recognition sensor that recognizes a user's fingerprint, and performs authentication on the user by comparing fingerprint information input through the fingerprint recognition sensor with pre-stored fingerprint information. In addition, the user authentication result through the fingerprint recognition performed as described above is transmitted to the controller 340.

The status display unit 370 displays an operation state of the memory controller 320 or the fingerprint recognition unit 360 under the control of the controller 340. The status display unit 370 may be implemented as, for example, a light emitting diode (LED) having different colors to efficiently display the operating states of the memory controller 320 and the fingerprint recognition unit 360.

Finally, the RFID tag 380 transmits the SSD identification information to the outside using a radio frequency (RF). The RFID tag 380 may be implemented as an active or passive tag, and if the SSD having the RFID tag is out of a predetermined area, the RFID reader detects this and notifies the administrator to the confidentiality of the company, research institute, or public institution. Information can be prevented from leaking outside. For example, in the example of the public computer described above, the user (employee, researcher, etc.) can carry the SSD in a company or research lab and use the public computer as his personal computer, but cannot carry the SSD to the outside.

Hereinafter, a method of driving a solid state disk (SSD) having an authentication function according to the present invention will be described with reference to FIGS. 4 and 5.

First, FIG. 4 is a flowchart illustrating a method of driving an SSD having an authentication function according to an embodiment of the present invention, and illustrates a case in which the SSD according to the present invention is used as a general removable storage medium.

If the user plugs the SSD according to the present invention into a PCI-Express slot of a computer, for example, in step S410, the controller 340 is the first connection signal transmitted from the computer through the connector unit 330. Detect it. Then, in step S420, the controller 340 inactivates the memory controller 320 by cutting off the power provided from the connector unit 330 to the memory controller 320. Here, the power supply to the memory controller 320 is cut off, for example, the controller 340 transmits a memory controller deactivation signal to the power switching unit 350, and accordingly, the power switching unit 350 sends the memory controller 320 to the memory controller 320. This can be done by shutting off the provided power supply. For reference, when implemented as in the present invention, in most cases, the power supplied from the connector unit 330 to the memory controller 320 is cut off from the beginning before the SSD is connected to the computer. In this case, step S420 May be omitted.

In operation S430, the controller 340 authenticates a user by using at least one authentication scheme. For example, the controller 340 may perform authentication with a user by confirming a result of comparing fingerprint information input through the fingerprint sensor with pre-stored fingerprint information in cooperation with the fingerprint recognition unit 350 or the computer. The user can be authenticated by interworking with a user by inputting a password and comparing it with a previously stored PIN (Personal Identification Number).

In step S440, when authentication of the user performed using at least one authentication method is successful, the flow proceeds to step S450, where the controller 340, for example, supplies the power supplied from the connector unit 330 to the memory controller 320. Supply to activate the memory controller 320. Here, the power supplied to the memory controller 320 is, for example, the control unit 340 transmits the memory controller activation signal to the power switching unit 350 and accordingly the power switching unit 350 to the memory controller 320 This can be done by supplying the provided power.

In operation S460, the memory controller 320 is activated to enable the computer to use at least one flash memory 310-1,..., 310-n embedded in the SSD as a storage medium. Then, when the use of the SSD is completed and detects the disconnection signal from the computer, the control unit 340 cuts off the power provided from the connector unit 330 to the memory controller 320 through the power switching unit 350. To inactivate the memory controller 320 again.

On the other hand, in step S440, if the authentication for the user performed using at least one authentication method fails, the flow proceeds to step S470, the controller 340 determines whether the number of authentication failures for the user exceeds a predetermined threshold. To judge. If the number of authentication failures does not exceed the threshold, the process proceeds to step S430, where the controller 340 again authenticates the user using at least one authentication scheme.

However, if the number of authentication failures exceeds the threshold (i.e., when a user without proper authority fails authentication several times), the process proceeds to step S480, where the control unit 340 deletes data to the memory controller 320. The memory controller 320 deletes all data stored in the at least one flash memory 310-1,..., 310-n. Accordingly, the present invention may prevent leakage of confidential information by spontaneously deleting data stored in a flash memory even if theft or loss occurs.

5 is a flowchart illustrating a method of driving an SSD having an authentication function according to another embodiment of the present invention, which describes a case in which the SSD according to the present invention is used as a removable storage medium for implementing a personal computing environment.

If the user inserts the SSD according to the present invention into the computer before the computer is booted (eg, before turning on the computer) or during booting, in step S510, when the computer is booted, the control unit 340 is connected to the connector unit ( 330 senses a boot signal transmitted from the computer. Then, in step S520, the controller 340 transmits an interrupt signal for requesting boot interruption to the computer through the connector unit 330 to bring the boot control right to itself.

In operation S530, the controller 340 that receives the boot control right performs authentication on the user using at least one authentication method. For example, the controller 340 may perform authentication with a user by confirming a result of comparing fingerprint information input through the fingerprint sensor with pre-stored fingerprint information in cooperation with the fingerprint recognition unit 350 or the computer. The user can be authenticated by interworking with a user by inputting a password and comparing it with a previously stored PIN (Personal Identification Number).

In step S540, when authentication of the user performed using the at least one authentication method is successful, the flow proceeds to step S550, where the controller 340 controls the memory controller 320 to control at least one flash memory 310-1. , ..., 310-n to the OS program is transmitted to the computer via the connector unit 330. Then, the computer is not driven by the OS program stored in its own hard disk but is driven by the OS program stored in the SSD according to the present invention, so that the user can implement his or her computing environment anytime and anywhere regardless of the computer. do.

In operation S560, the user may use at least one flash memory 310-1,..., 310-n embedded in his SSD as a storage medium by using the computer. By separating the SSD from the computer, information security can be maintained. In particular, when using a public computer without an internal storage medium (for example, a hard disk) as described above, since no information remains on the public computer after use, the effect of information security can be maximized.

On the other hand, in step S540, if the authentication for the user performed using at least one authentication method fails, proceeds to step S570, the control unit 340 determines whether the number of authentication failures for the user exceeds a predetermined threshold. To judge. If the number of authentication failures does not exceed the threshold, the process proceeds to step S530 where the controller 340 again authenticates the user using at least one authentication scheme.

However, if the number of authentication failures exceeds the threshold (i.e., a user without proper authority has failed several authentications), the flow proceeds to step S580, where the controller 340 deletes data to the memory controller 320. The memory controller 320 deletes all data stored in the at least one flash memory 310-1,..., 310-n. Accordingly, the present invention may prevent leakage of confidential information by spontaneously deleting data stored in a flash memory even if theft or loss occurs.

Although the present invention has been described in detail with reference to preferred embodiments, it will be apparent to those skilled in the art that the present invention may be embodied in other specific various forms without changing the technical spirit or essential features of the present invention. One embodiment is to be understood in all respects as illustrative and not restrictive.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. .

1 is a block diagram of an SSD according to the prior art.

2 is a diagram illustrating an external appearance of an SSD having an authentication function according to the present invention.

3 is a block diagram of an SSD having an authentication function according to an embodiment of the present invention.

4 is a flowchart illustrating a method of driving an SSD having an authentication function according to an embodiment of the present invention.

5 is a flowchart illustrating a method of driving an SSD having an authentication function according to another embodiment of the present invention.

Claims (20)

As a solid state disk (SSD) having an authentication function, A connector unit connected to a computer to perform data transmission and reception; At least one flash memory storing data transmitted and received with the computer; A memory controller controlling the at least one flash memory; And When the first connection signal with the computer is detected through the connector unit, the memory controller is inactivated, the user is authenticated using at least one authentication method, and then the user is successfully authenticated. And a controller for activating the memory controller. The method of claim 1, And a power switching unit for switching the power provided from the connector unit to the memory controller according to an activation signal or an inactivation signal for the memory controller transmitted from the control unit. The method of claim 1, And a fingerprint recognition unit configured to authenticate the user by comparing fingerprint information input through a fingerprint recognition sensor with pre-stored fingerprint information in association with the controller. The method of claim 3, Under the control of the control unit, the SSD further comprises a status display unit for displaying an operating state of at least one of the memory controller and the fingerprint recognition unit. The method of claim 1, And the controller communicates with the computer through the connector to perform PIN (Personal Identification Number) authentication for the user. 6. The method according to any one of claims 1 to 5, The connector unit SSD characterized in that it comprises a Peripheral Component Interconnect Express (PCI-Express) interface. 6. The method according to any one of claims 1 to 5, And said at least one flash memory is a multi level cell (MLC) memory. 6. The method according to any one of claims 1 to 5, And said at least one flash memory is two or more flash memories, and said data is fragmented and dividedly stored in two or more flash memories. Solid State Disk (SSD) with authentication function, A connector unit connected to a computer to perform data transmission and reception; At least one flash memory storing a computer operating system (OS) program; A memory controller controlling the at least one flash memory; And When the boot signal is detected from the computer through the connector, an interrupt signal is requested to stop the boot, the user is authenticated using at least one authentication method, and then authentication of the user is successful. And a controller for transmitting an OS program stored in the at least one flash memory to the computer. 10. The method of claim 9, Under the control of the controller, the SSD further comprises a fingerprint recognition unit for performing authentication for the user by comparing the fingerprint information input through the fingerprint recognition sensor with the pre-stored fingerprint information. 11. The method according to claim 9 or 10, And the controller communicates with the computer through the connector to perform PIN (Personal Identification Number) authentication for the user. 11. The method according to claim 9 or 10, The connector unit SSD characterized in that it comprises a Peripheral Component Interconnect Express (PCI-Express) interface. A method of driving a solid state disk (SSD) having an authentication function, a) inactivating the memory controller upon detecting an initial connection signal with the computer; b) performing authentication for the user using at least one authentication scheme; And c) when the authentication of the user is successful, activating the memory controller. The method of claim 13, The at least one authentication method includes at least one of a personal identification number (PIN) authentication method and an authentication method through fingerprint recognition. The method according to claim 13 or 14, Deactivation of the memory controller is performed by cutting off power provided from the connector unit to the memory controller, Activation of the memory controller is performed by supplying power provided from the connector to the memory controller. The method according to claim 13 or 14, and d) deactivating the memory controller again when detecting a disconnection signal from the computer. A method of driving a solid state disk (SSD) having an authentication function, a) if it detects a boot signal from the computer, transmitting an interrupt signal to the computer requesting a boot stop; b) performing authentication for the user using at least one authentication scheme; And c) when the authentication of the user is successful, transmitting an OS (Operating System) program stored in at least one flash memory to the computer. The method of claim 17, The at least one authentication method includes at least one of a personal identification number (PIN) authentication method and an authentication method through fingerprint recognition. The method of claim 17 or 18, and d) deactivating a memory controller controlling the at least one flash memory upon detecting a disconnection signal from the computer. The method of claim 19, Deactivation of the memory controller is performed by cutting off the power provided from the connector to the memory controller.

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