JP2012104170A - Hard disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the security of data in HDD in a short time by using speed which is almost the same as the normal access speed to HDD and in a time zone in which data access cannot be affected.SOLUTION: An HDD device includes HDD15, its control part (for example, CPU13), a random number generating part (for example, random number generating device 12) which generates a random number which is unique to the HDD device and can be reproduced in the HDD device, a data switching part (for example, scramble control part 17 and a temporary memory 19) for switching the data in the HDD15 by a logical sector unit based on the random number generated in the random number generating device 12 at the time of switch off of the HDD device.

Description

  The present invention relates to a hard disk device including a hard disk and a control unit that controls the hard disk.

  2. Description of the Related Art Conventionally, in a hard disk device, in order to increase security, a technique for performing encryption at the time of data recording or scrambling a logical address in units of sectors has been used.

  For example, Patent Document 1 discloses a recording / reproducing apparatus that aims to eliminate the risk of data being stolen when the data itself is encrypted and recorded on a recording medium.

  The recording / reproducing apparatus is configured to store a key information storage unit for storing predetermined key information and a logical address of each sector on the recording medium based on the key information when recording input data on a predetermined recording medium in units of sectors. A scramble recording means for recording while scrambled, and a scramble release reading means for reading out the logical address of each scrambled sector based on the key information when reading the data recorded on the recording medium in units of sectors. It has.

JP 2000-76136 A

  However, in the conventional technology related to recording with encryption, it takes time for encryption processing and encoding processing, and it takes time for data access, and the entire hard disk (HDD: Hard Disk Drive) is encrypted. Takes time.

  Since the technique described in Patent Document 1 is also a technique for encrypting a logical address itself by scrambling, similarly, it takes time to access data, and it also takes time to encrypt the entire HDD. . Further, the technique described in Patent Document 1 has another problem that it takes time to access a sector because the order of sectors to be replaced by scramble is not taken into consideration.

  The present invention has been made in view of the above circumstances, and its purpose is to affect data access in an HDD device in a short time and at a speed not much different from the normal access speed to the HDD. The purpose is to increase the security of data in the HDD in the absence of time.

  Another object of the present invention is to consider the order of sectors to be replaced by scrambling in such an HDD device, thereby further speeding up the access and reducing the access speed to the same level as the normal access speed to the HDD. In addition, it is to increase the security of data in the HDD.

  In order to solve the above-described problem, a first technical means of the present invention is a hard disk device including a hard disk and a control unit that is connected to the hard disk and controls the hard disk, and is unique to the hard disk device. And a random number generator for generating a random number that can be reproduced by the hard disk device, and when the hard disk device is powered off, the data in the hard disk is converted into logical sector units based on the random number generated by the random number generator. And a data exchanging unit for exchanging the data.

  A second technical means is characterized in that, in the first technical means, the data exchange unit selects a data movement destination in each logical sector from the same track and / or a logical sector in an adjacent track. It is a thing.

  According to the HDD apparatus of the present invention, the security of data in the HDD can be increased in a short time and at a time zone that does not affect data access by a speed that is not significantly different from the normal access speed to the HDD.

  Also, according to the HDD device according to another aspect of the present invention, since the order of sectors to be replaced by scramble is also taken into consideration, the access speed is further increased and the access speed is reduced to the same level as the normal access speed to the HDD. In addition, the security of data in the HDD can be increased.

It is a block diagram explaining an example of the electronic device provided with the HDD apparatus which concerns on this invention. FIG. 2 is a diagram for explaining tracks and sectors on an HDD in the electronic apparatus of FIG. 1. It is a flowchart for demonstrating the process at the time of turning off a power supply performed in the electronic device of FIG. It is a flowchart for demonstrating an example of the scramble process in the process of FIG. FIG. 5 is a flowchart for explaining a part of random number generation processing in the scramble processing of FIG. 4. It is a figure for demonstrating the specific example of the scramble process of FIG. FIG. 5 is a flowchart for explaining an example of a descrambling process for releasing the scrambling process of FIG. 4. It is a figure for demonstrating the specific example of the descrambling process of FIG.

  The HDD device according to the present invention can be mounted alone or by being mounted on an electronic device such as a multifunction machine or a personal computer (PC). Hereinafter, the present invention will be described with reference to an example mounted on an electronic device such as a multifunction peripheral, but the same applies to a case where it is mounted alone.

  FIG. 1 is a block diagram for explaining an example of an electronic apparatus equipped with an HDD device according to the present invention, and FIG. 2 is a diagram for explaining tracks and sectors on the HDD in the electronic apparatus of FIG. The electronic device illustrated in FIG. 1 includes the HDD device according to the present invention, and FIG. 1 mainly shows the part of the HDD device.

  The HDD device according to the present invention is a kind of storage device, and includes an HDD 15 that is a disk coated with a magnetic material, and a control unit that is connected to the HDD 15 and controls the HDD 15. By rotating and moving the magnetic head, information is recorded and read out.

  In FIG. 1, this control unit can be exemplified mainly by a CPU (Central Processing Unit) 13 and a disk I / F 16. The CPU 13 is a main control unit of the electronic device 1 and also controls the HDD device. The disk I / F 16 is an interface for accessing the HDD 15 to read and write data. As this standard, for example, SATA (Serial Advanced Technology Attachment) or eSATA (external Serial ATA) may be adopted.

  The electronic device 1 includes a host I / F 18 such as a universal serial bus (USB) or a small computer system interface (SCSI), and is connected to a PC 2 as an example of a host of the electronic device 1 including an HDD device. Even when the HDD device is mounted alone, the HDD device may be configured to have an interface such as the host I / F 18 and be accessed from the host side.

  The HDD device according to the present invention includes a random number generation unit that generates a random number unique to the HDD device and reproducible by the HDD device. In FIG. 1, this random number generator is exemplified by a random number generator 12. The random number generator 12 preferably holds, for example, key information unique to the HDD device with high tamper resistance, and may generate a pseudo random number based on the key information. Since the random number generator 12 generates reproducible random numbers for each device, the random number generator 12 is different from the random numbers generated by other HDD devices.

  The electronic device 1 also includes a power control unit 11 that controls power and a power key 14. The power key 14 is a key for turning on / off the power of the electronic device 1, and the power control unit 11 is a part for controlling the power of the electronic device 1. Here, the power supply of the HDD device incorporated in the electronic device 1 is also described as being turned on / off by the power supply control unit 11 in response to the on / off operation of the power key 14, but the power key 14 of the electronic device 1 is also described. Alternatively, the HDD device may be configured to be able to turn on / off.

  Further, the on / off operation may be configured not only by a key such as the power key 14 but also by an instruction from an external device such as the PC 2. That is, when turning on or turning off the power of the HDD device described later, this refers to the time when such an on / off operation is detected.

  Furthermore, the HDD device according to the present invention includes the following data exchange unit as its main feature. The data exchange unit stores data in the HDD 15 based on the random number generated by the random number generator 12 when the HDD device is turned off (that is, when the HDD device is turned off). Are replaced in units of logical sectors.

  Here, the logical sector will be described with reference to FIG. As shown in FIG. 2, the single disk 15 d is illustrated, and the physical sector and logical sectors 31 to 33 on the HDD 15 divide the track 30 that is a concentric circle of the disk 15 d into a plurality of areas. Can be defined as the minimum accessible storage area. In FIG. 2, 2048-byte logical sectors 32, 31,..., 33 indicated by sector numbers 1, 2,. In the case of an HDD, typically, one sector is 512 bytes, and 512 bytes of data can be accessed per sector. However, in recent years, in order to improve the recording density, for example, 2048 bytes or HDD devices that have been expanded to 4096 bytes or the like, and logical sectors have been expanded to 2048 bytes, 4046 bytes, or the like for the purpose of expanding the capacity of the HDD, have begun to circulate.

  Supplementally, the logical sector refers to a logical sector on the HDD device side, and is also called AFT (Advanced Format Technology) or BigSector. On the other hand, management of the storage medium including the HDD by the operation system (OS) of the PC 2 is usually performed not in units of sectors but in units of “clusters” in which several sectors are combined. Further, since the data exchange unit exchanges data in the HDD 15 (all data on the HDD 15), if the logical sector and the physical sector are not the same size, the physical sector can be basically processed even in units of logical sectors. It is not handled in units. Therefore, it is preferable from the viewpoint of access speed that the logical sector and the physical sector have the same size and the sector boundaries of the two coincide.

  A replacement method in the data replacement unit will be described. The replacement method is to select a pair of logical sectors, move the data of one logical sector to the other logical sector of the pair, move the data of the other logical sector to one logical sector, etc. Exchange (exchange within a pair) may be performed. However, for example, if there are logical sectors A, B, and C, they may be replaced by moving to write the data of the original logical sectors B, C, and A, respectively.

  In FIG. 1, this data exchange unit is exemplified by a scramble control unit 17 and a temporary storage memory 19. First, the scramble control unit 17 is configured to be able to read data in the HDD 15 and write data to the HDD 15 via the disk I / F 16. Further, the scramble control unit 17 replaces data in the HDD 15 in units of logical sectors based on the random number generated by the random number generator 12 according to an instruction from the CPU 13 resulting from the power-off operation, that is, each of the HDD devices. A process of replacing data in the logical sector is performed. Here, the scramble control unit 17 does not change the code arrangement of the data itself in the logical sector. In the scramble process, a temporary storage memory 19 such as an SRAM (Static Random Access Memory) is used as a buffer.

  The processing as described above will be described with reference to specific examples with reference to FIGS. FIG. 3 is a flowchart for explaining processing when the power is turned off, which is executed in the electronic apparatus of FIG. 1. 4 is a flowchart for explaining an example of the scramble process in the process of FIG. 3, FIG. 5 is a flowchart for explaining a part of the random number generation process in the scramble process of FIG. 4, and FIG. FIG. 5 is a diagram for explaining a specific example of the scramble process of FIG. 4.

  A rough processing flow will be described with reference to FIG. The CPU 13 detects by interruption that the power-off operation has been performed by the power key 14 (step S1), the CPU 13 instructs the scramble control unit 17 to perform scramble processing, and the scramble control unit 17 performs scramble processing (step S2). . After the scramble process, the CPU 13 instructs the power control unit 11 to turn off the power (step S3).

  The high-speed scramble process in step S2 performed mainly by the scramble control unit 17 will be described with reference to FIG. First, the data of all logical sectors of one track are read out to the temporary storage memory 19 (step S11). Prior to this, or after the processing of step S11, the CPU 13 instructs the random number generator 12 to generate a random number. The random number generator 12 generates random numbers corresponding to the number of logical sectors accordingly (step S12). The CPU 13 passes the random number to the scramble control unit 17, and the scramble control unit 17 temporarily stores the random number in the temporary storage memory 19, and writes the data to the logical sector (corresponding to the logical sector) using the random number as the writing sector number. (Step S13).

  Supplementing step S12, as shown in FIG. 5, the random number generator 12 acquires the serial number of the HDD device before the process of step S11 (or before the power-off operation) or after the process of step S11. (Step S21), a random number seed (initial value) is generated based on the serial number (Step S22). By generating a random number in step S12 based on such an initial value, it is possible to generate a random number that is unique to the HDD device and can be reproduced. The serial number is an example of device-specific information.

  How actual data is rewritten by such a scramble process will be described. The case where “0” to “7” indicated by the read sector number 41 as the target of the scramble process as shown in FIG. 6 will be described. A random number 42 is generated for each logical sector, and the read sector number 43 is used as it is. Use to write data. In this example, the data in the read sector numbers 41 “0” to “7” have write sector numbers 43 of “2”, “7”, “1”, “5”, “3”, “6”, The data is written at the positions indicated by “4” and “0”.

  In this example, a random number is used as it is, and the data is replaced with a logical sector with a sector number corresponding to the generated random number. May be executed. Of course, in order to perform processing for improving security at a speed closer to the access speed of the HDD 15, it is preferable to employ a simple calculation, but scrambling processing by high-speed logical sector replacement requires less data movement time. For this reason, even if a complicated calculation is employed, the working time itself can be shortened.

  Next, processing when the power is turned on will be described with reference to FIGS. FIG. 7 is a flowchart for explaining an example of the descrambling process for releasing the scrambling process of FIG. 4, and FIG. 8 is a diagram for explaining a specific example of the descrambling process of FIG. FIG. 8 shows an example corresponding to the specific example of FIG.

  Even during the power-on operation, as in FIG. 5, the scramble controller 17 first reads all logical sector data of one track into the temporary storage memory 19 (step S31). Prior to this (however, of course, after the power is turned on) or after the processing in step S31, the CPU 13 instructs the random number generator 12 to generate a random number. The random number generator 12 generates random numbers corresponding to the number of logical sectors accordingly (step S32).

  Next, the CPU 13 passes the random number to the scramble control unit 17, and the scramble control unit 17 stores the random number and the random number generation order in the temporary storage memory 19 as a set 52, sorts the random numbers in ascending order, and sorts by set. A random number generation number (after sorting) 53 is calculated (step S33). Next, the scramble control unit 17 writes the data in the logical sector (corresponding position) with the random number generation number (after sorting) as the write sector number 54 (step S34).

  For example, when the read sector number 41 of the data read as the scramble processing target is “7”, the data is written to the logical sector whose write sector number 43 is “0” by the scramble processing. When the read sector number 51 read as the descrambling target is “0”, the write sector number 54 is written in the logical sector “7” by the descrambling process. As described above, the state before the scramble process is restored, and it can be seen that the data recording position of the HDD 15 can be restored by performing the scramble process and the release process by such a sector number calculation process.

  The processes in steps S31 to S34 are performed first when the power-on operation is detected, and the data is returned to the original state (the state before the power-off operation). As described above, when the HDD device is powered on, the HDD is restored to the original data position, thereby enabling normal HDD access only by the corresponding HDD device. Here, the reason that access is possible only with the corresponding HDD device is that a random number unique to the HDD device is used, and even if restoration is attempted with another HDD device, the random number cannot be reproduced.

  In addition, the description is based on the assumption that the power-on operation is first performed. However, the scramble process during the power-off operation may be performed on each area divided by an integer multiple of logical data as a boundary. For example, as long as it is an area that does not contain an activation program such as an OS, the descrambling process may be performed when only the necessary area is required after the power-on operation. Moreover, as this area | region, you may employ | adopt the area | region defined by one or several track | trucks so that it may mention later.

  As described above, according to the HDD device of the present invention, the security of data in the HDD can be increased in a short time and at a time zone that does not affect data access by a speed that is not significantly different from the normal access speed to the HDD. it can. In other words, according to the present invention, by the work that can be performed at a high speed of switching the data to the position generated by the random number in a short time when switching from the power-on state to the power-off state, Security can be increased at high speed. In addition, although it has been described that the destination may be determined by performing a complex calculation based on a random number, the access time of the HDD 15 may not be affected so much, and if there is not so much influence, data inversion or Even if a configuration for adding processing such as bit replacement is adopted, there is no problem.

  In the above-described various examples, there is no particular restriction on the logical sector to be replaced. However, in order to make access faster, the data movement destination is better. Therefore, it is preferable that the data exchange unit selects a data movement destination in each logical sector from the same track and / or a logical sector in an adjacent track. When a pair is created and exchanged, two logical sectors to be exchanged may be selected from the same track or adjacent tracks.

  In this way, by reading the logical sectors of the same track or adjacent tracks all at once and exchanging between the logical sectors, the movement of the magnetic head can be minimized, thereby speeding up. In a configuration in which selection is made from logical sectors in the same track, the temporary storage memory 19 only needs to have a storage capacity of at least one track. Similarly, in the configuration in which selection is made from logical sectors in adjacent tracks (and the same track), the temporary storage memory 19 only needs to have a storage capacity of at least two tracks. More specifically, if the scramble control unit 17 reads out the first track, stores the data in the temporary storage memory 19, and writes the logical sector data replaced with the next track, the track is rotated twice (two tracks). The replacement is completed in (Track).

  In this way, by considering the order of the logical sectors to be replaced by scrambling, the access is further accelerated, and as a result, at a speed similar to the normal access speed to the HDD 15 (that is, Write + Read access of the HDD 15). In time), the security of data in the HDD 15 can be increased. That is, according to the HDD device adopting this form, it is as short as the access speed of the HDD 15 and in a time zone that does not affect data access, that is, in a limited time until the power is turned off. The security of data in the HDD 15 can be increased. In other words, in the HDD device according to this aspect, the security level can be adjusted only by the time for moving the data.

DESCRIPTION OF SYMBOLS 1 ... Electronic device, 2 ... PC, 11 ... Power supply control part, 12 ... Random number generator, 13 ... CPU, 14 ... Power key, 15 ... HDD, 15d ... Disk, 16 ... Disk I / F, 17 ... Scramble control part , 18 ... Host I / F, 19 ... Temporary storage memory, 30 ... Track, 31, 32, 33 ... Logical sector.

Claims (2)

  A hard disk device including a hard disk and a control unit connected to the hard disk and controlling the hard disk, the random number generating unit generating a random number specific to the hard disk device and reproducible by the hard disk device; A hard disk device further comprising a data replacement unit that replaces data in the hard disk in units of logical sectors based on the random number generated by the random number generation unit when the power of the hard disk device is turned off. .   2. The hard disk device according to claim 1, wherein the data exchange unit selects a data movement destination in each logical sector from the same track and / or a logical sector in an adjacent track.

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