AT527294B1 - data processing system for trusted computing - Google Patents

Abstract

A data processing system (1) comprises a processor unit (2), at least two selectively connectable mass storage devices (6i) and either a trusted platform module (8) with at least two switchable register banks (PCRi) or at least two switchable physical or virtual trusted platform modules (8i). One of the register banks (PCRi) or one of the trusted platform modules (8i) is activated in accordance with the connected mass storage device (6i) or one of the trusted platform modules (8i) is connected together with the respective mass storage device (6i).

Description

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Description

[0001] The present invention relates to a data processing system comprising a central processor unit which is fed by a power supply, at least two mass storage devices, one of which can optionally be connected to the central processor unit via a first data bus, and a trusted platform module which can be connected to the central processor unit via a second data bus.

[0002] A data processing system with a Trusted Platform Module (TPM) is also referred to as a Trusted Computing Platform (TC Platform). The TPM is a hardware or software element according to the TPM specification, which is standardized by the Trusted Computing Group (TCG), see e.g. "Trusted Platform Module (TPM) Summary" from April 29, 2008 by the TCG at www.trustedcomputinggroup.org, most recently in version TPM 2.0. In practice, the TPM is usually designed as a separate hardware chip that is directly connected to the central processing unit via its own data bus, for example a serial bus according to the SPI (Serial Peripheral Interface), LPC (Low Pin Count) or i°C standards.

[0003] A TPM can be used for many security applications within the data processing system. For example, it provides a random number generator, cryptographic encryption algorithms, keys and protected storage areas for encrypted data. In connection with mass storage devices, the TPM can be used, for example, for hardware-level encryption of the contents of the mass storage device. Or the TPM serves as a protected storage for encrypted hash values of snapshots of the hardware and/or the operating system stored on a mass storage device when the operating system is booted in order to verify its software integrity or to ensure correct hardware assignment. For example, DE 10 2015 115 533 A1 discloses a data processing system with a redundant storage drive arrangement - also known as a "Redundant Array of Independent Disks" (RAID) - which has, among other things, a connection for a TPM. The TPM is used to authenticate systems that are seeking memory access.

[0004] The use of one and the same data processing system with different operating systems stored on different mass storage devices or with differently encrypted mass storage devices is difficult with the known solutions. The invention aims to overcome these limitations and to create a data processing system which can provide mass storage-related TPM services for use with different mass storage devices.

[0005] This aim is achieved in a first embodiment of the invention with a data processing system of the type mentioned in the introduction, which is characterized by a microcontroller that can be connected to the second data bus, wherein the trusted platform module has at least two register banks of platform configuration registers, of which only one register bank is active in an operating mode of the data processing system and the active register bank can be set by a control command received from the microcontroller, wherein the microcontroller is designed to set the active register bank in a configuration mode of the data processing system by means of the control command in accordance with the mass storage device selected for the operating mode.

[0006] Preferably, in this embodiment, the data processing system has a switch which is adjustable by the microcontroller and connected to the second data bus, which connects the trusted platform module either to the central processor unit or to the microcontroller, wherein the microcontroller is designed to connect the trusted platform module to the central processor unit in the operating mode and to the microcontroller in the configuration mode by means of the switch.

[0007] In a second embodiment, the invention achieves its objective with a data processing system of the type mentioned in the introduction, which is characterized by a microcontroller and a switch adjustable by the microcontroller and connected to the second data bus,

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which connects the central processor unit in an operating mode of the data processing system via the second data bus either to the first trusted platform module or to a second trusted platform module, wherein the microcontroller is designed to set the switch in a configuration mode of the data processing system according to the mass storage selected for the operating mode.

[0008] In a third embodiment, the invention provides a data processing system of the type mentioned in the introduction, which is characterized by a microcontroller which is connected to the second data bus and is designed to emulate both the first trusted platform module and a second trusted platform module as a software instance, of which software instances only one is active in an operating mode of the data processing system, wherein the microcontroller is designed to set the active software instance in a configuration mode of the data processing system according to the mass storage device selected for the operating mode.

[0009] In this embodiment, the two Trusted Platform modules of the second embodiment are implemented as software instances in the microcontroller, which simplifies the practical implementation.

[0010] In all three embodiments mentioned, it is particularly favorable if each mass storage device is provided with a machine-readable identifier and the microcontroller is connected to a reader for reading identifiers and is designed to detect the mass storage device selected for the operating mode on the basis of the identifier read by the reader.

[0011] Preferably, the configuration mode is alternative to the operating mode, but could also be temporarily adopted in parallel to the operating mode.

[0012] In a fourth embodiment, the invention achieves the stated object with a data processing system of the type mentioned in the introduction, which is characterized by a second TrustedPlatform module that can be optionally connected to the second data bus instead of the first TrustedPlatform module, wherein one of the mass storage devices and one of the TrustedPlatform modules that is assigned to this mass storage device are arranged in a common transport housing that is detachably connected to the rest of the data processing system.

[0013] In each of the four embodiments mentioned, the data processing system according to the invention enables the optional use of different mass storage devices, for example loaded with different operating systems or encrypted in different ways, in connection with the TPM services of a TPM individually configured for the respective mass storage device or individually configured Platform Configuration Registers (PCRs) of a TPM.

[0014] By using a switch, it can be ensured in the first two embodiments that the TPM only ever communicates with a single component on the bus via the second data bus, thus avoiding communication disruptions. In addition, this embodiment is particularly suitable for simple TPMs that are not equipped for multi-partner communications.

[0015] In the fourth embodiment, in which a TPM and a mass storage device are combined in a separate housing that can be connected to the rest of the data processing system, instead of selectively switching a switch, a different transport housing can simply be optionally connected. The invention thus creates a new product, namely an exchangeable unit consisting of mass storage device and TPM that can be used interchangeably with one and the same central processing unit.

[0016] In the first three embodiments, provision can preferably be made to interrupt the power supply of the central processing unit in configuration mode. As a result, the central processing unit restarts after returning to the operating mode and thus switching the power supply back on and continues using the respectively connected

mass storage and associated TPMs.

[0017] The first data bus can be designed according to any state of the art known in the art that is suitable for connecting mass storage devices. The first data bus is preferably designed according to one of the standards USB, USB-C, Thunderbolt, SATA, eSATA, PCI or PCIe.

[0018] The second data bus can also be designed according to any standard known in the art that is suitable for connecting TPMs. The second data bus is preferably designed according to one of the standards i2C, SPI or LPC.

[0019] In all the above-mentioned embodiments, each of the mass storage devices is preferably a semiconductor hard disk or a non-volatile memory chip.

[0020] The invention is explained in more detail below with reference to embodiments shown in the accompanying drawings. In the drawings:

[0021] Fig. 1 shows a first embodiment of the data processing system of the invention in a block diagram;

[0022] Fig. 2 shows a second and a third embodiment of the data processing system of the invention in a block diagram; and

[0023] Fig. 3 shows a fourth embodiment of the data processing system of the invention in a block diagram.

[0024] Fig. 1 shows a first embodiment of a data processing system 1. The data processing system 1 comprises a central processor unit 2 to which a working memory 3 and at least one input/output unit 4, e.g. a screen, a keyboard, a touchscreen, a printer, a network adapter and/or any input/output interface, are connected.

[0025] One of several mass storage devices 6", 6, ..., generally 6;, can be optionally connected to the central processor unit 2 via a first data bus 5. The mass storage devices 6; are in particular persistent mass storage devices, i.e. they store their contents for a long time even without a power supply. Examples of such persistent mass storage devices are magnetic or optical hard disks, semiconductor hard disks or non-volatile memory chips such as FlashRAMs, ROMs, PROMs, EPROMs, EEPROMs, SSDs (Solid State Disks), etc. The first data bus 5 can be designed according to a standard suitable for such mass storage devices 6;, for example according to the USB, USB-C, Thunderbolt, SATA, eSATA, PCI or PCle standards.

[0026] A trusted platform module (TPM) 8 is connected to the central processor unit 2 via a second data bus 7, in the example shown via a switch 9 that is connected to the second data bus 7. The TPM 8 is a trusted platform module according to a TPM standard of the Trusted Computing Group (TCG), for example according to the TPM 1.2 or TPM 2.0 standard. The TPM 8 provides the data processing system 1 with standardized TPM services and has at least one bank of platform configuration registers (PCR) for storing keys, hash values, etc., as they can be stored or retrieved via the second data bus 7 (e.g. encrypted).

[0027] In the example shown here, the TPM 8 has two or more banks PCR+4, PCR, ..., generally PCR;, of platform configuration registers. By means of an internal switch 10 in the TPM 8, the ("active") register bank PCR; used in the operating mode of the data processing system 1, i.e. when the central processor unit 2 wants to communicate with the TPM 8 via the data bus 7, can be selected.

[0028] To set the switches 9 and 10, the data processing system 1 comprises a microcontroller 11. The microcontroller 11 is either permanently connected to the second data bus 7 or - as in the example shown - can be connected to the TPM 8 via the switch 9 instead of the central processor unit 2. In the operating mode of the data processing system 1 shown in Fig. 1, the switch 9, if present, is in the position shown.

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lower switch position so that the microcontroller 11 is disconnected from the second data bus 7 and is inactive. If, however, no switch 9 is used, i.e. both the microcontroller 11 and the TPM 8 are connected to the second data bus 7 of the central processor unit 2, the microcontroller 11 refrains from any communication on the second data bus 7 in the operating mode of the data processing system 1 in order not to disrupt the communication between the TPM 8 and the central processor unit 7.

[0029] The data processing system 1 can be put into a special configuration mode - in addition to or in particular as an alternative to its operating mode. If a switch 9 is present, the switch 9 is then put into its upper position in Fig. 1 and the TPM 8 is thereby connected to the microcontroller 11 via the second data bus 7. The microcontroller 11 can itself cause the switch 9 to switch, see control path 12.

[0030] In configuration mode, the microcontroller 11 sends a control command 13 to the TPM 8 via the second data bus 7 to set the TPM-internal switch 10, see the dotted control path, in order to select one of the PCR register banks PCR: in the TPM 8 as the "active" register bank for further operation. After leaving the configuration mode and re-entering the operating mode, i.e. after moving the switch 9 to the lower position shown in Fig. 1, if present, or after the microcontroller 7 abstains from any further communication on the data bus 7, the selected register bank PCR: is now used by the central processor unit 2. The central processor unit 2 does not notice that the active PCR register bank PCR; in the TPM 8 has changed. If no switch 9 is used, the configuration mode can also be entered only temporarily during the operating mode.

[0031] Optionally, in configuration mode, a power supply 14 feeding the central processor unit 2 can be interrupted by the microcontroller 11 via a controllable switch 15 and a corresponding control path 16. This also makes it possible to achieve exclusive communication between the microcontroller 11 and the TPM 8 in configuration mode, in particular if no switch 9 is provided.

[0032] The microcontroller 11 is programmed in such a way that it initiates the selection of the respective register bank PRC; by controlling the switch 10 depending on the mass storage device 6; currently connected to the first data bus 5. For the first mass storage device 6+, the microcontroller 11 sets, for example, the first register bank PCR;, for the second mass storage device 62 the second register bank PCR2, etc.

[0033] The microcontroller 11 can receive the information about which mass storage device 6; is connected or should be connected to the first data bus 5 in the operating mode, for example via an input device 17, i.e. the user connects the respective mass storage device 6; to the data bus 5 on the one hand and sets the microcontroller 11 accordingly via the input device 17 on the other. Alternatively, the microcontroller 11 can receive this information automatically from the first data bus 5 via a corresponding data connection 18. Another possibility is that the microcontroller 11 is connected to a reader 19 that reads out a corresponding identification 20 of the respective mass storage device 6;. The identification 20 can be, for example, a barcode, an RFID tag or the like that is attached to or in the mass storage device 6;. The reader 19 can be a corresponding barcode reader, RFID reader or the like. However, the identification 20 can also be stored, for example, in a special section or module of the mass storage device 6; which can be read by the reading device 19; the reading device 19 can then be, for example, a corresponding interface.

[0034] Fig. 2 shows a second and a third embodiment of the data processing system 1, whereby only the differences compared to the embodiment of Fig. 1 are discussed here. Instead of a single TPM 8, the data processing system 1 has several TPMs 8:1, 82, ..., generally 8..

[0035] In the second embodiment, the various TPMs 8; are physical units and can be alternatively connected to the central processor unit 2 via a switch 21 connected to the second data bus 7. The microcontroller 11 is now programmed such that in the configuration mode it connects a TPM 8; assigned to a mass storage device 6; to the central processor unit 2 via the switch 21 and the data bus 7. Everything else, such as the selection or recognition of the mass storage device 6; used in the operating mode by the microcontroller 11 for the purpose of controlling the switch 21, takes place as described in the embodiment of Fig. 1 for controlling the TPM-internal switch 10.

[0036] In the third embodiment, the TPMs 8; are implemented as software instances in the programming of the microcontroller 11, as symbolized by the dash-dotted frame 11'. The switch 21 is also accordingly a software component in the programming of the microcontroller 11. It is understood that such software instances can also be implemented in a firmware that is used to program the microcontroller 11. The microcontroller 11 is now programmed in such a way that in configuration mode it sets the TPM 8; assigned to the respective mass storage device 6; via the software switch 21 and connects it to the data bus 7. Everything else, such as the selection or recognition of the respective mass storage device 6; used in the operating mode by the microcontroller 11 for the purpose of controlling the switch 11 and setting the corresponding emulated TPM 8; is again carried out as described in the embodiment of Fig. 1 for the control of the TPM-internal switch 10.

[0037] Fig. 3 shows a fourth embodiment of the data processing system 1, which does not require a switch 10 or 21 for selecting between different register banks PCR; of a TPM 8 or between different TPMs 8;. In Fig. 3, a TPM 8; with the mass storage device 6; assigned to it is arranged in a separate transport housing 224, 22, ..., generally 22;. Each transport housing 22; can be detachably connected to the remaining part 23 of the data processing system 1, via an interface 24, which comprises a first interface 25 for detachable connection to the first data bus 5 and a second interface 26 for detachable connection to the second data bus 7 for each transport housing 22;.

[0038] The transport housing 22; can, for example, be the housing of a memory stick or an SSD, which in addition to the mass storage interface 25 for the mass storage 6; has the further interface 26 for the integrated TPM 8;.

[0039] In this fourth embodiment, the TPM 8; can again be emulated as a software instance by a microcontroller in the mass storage 6; if desired. It is understood that such software instances can also be implemented as firmware of the microcontroller.

[0040] The data processing system 1 can be designed in any form and for any purpose, for example as a server, terminal, computer, notebook, laptop, PDA (Personal Digital Assistant), smartphone or the like.

[0041] The invention is not limited to the embodiments shown, but includes all variants, modifications and combinations thereof that fall within the scope of the appended claims.

Claims (11)

patent claims 1. Data processing system, comprising a central processor unit (2) which is fed by a power supply (14), at least two mass storage devices (6;), one of which can optionally be connected to the processor unit (2) via a first data bus (5), and a trusted platform module (8) which can be connected to the processor unit (2) via a second data bus (7), characterized by a microcontroller (11) which can be connected to the second data bus (7), wherein the trusted platform module (8) has at least two register banks (PCR;) of platform configuration registers, of which only one register bank (PCR)) is active in an operating mode of the data processing system (1) and the active register bank (PCR)) can be set by a control command (13) received from the microcontroller (11), wherein the microcontroller (11) is designed to set the active register bank (PCR;) in a configuration mode of the data processing system (1) by means of the control command (13) in accordance with the mass storage device (6;) selected for the operating mode. 2, Data processing system according to claim 1, characterized by a switch (9) which can be set by the microcontroller (11) and is connected to the second data bus (7), which connects the trusted platform module (8) either to the processor unit (2) or to the microcontroller (11), wherein the microcontroller (11) is designed to connect the trusted platform module (8) to the processor unit (2) in operating mode and to the microcontroller (11) in configuration mode by means of the switch (9). 3. Data processing system, comprising a central processor unit (2) which is fed by a power supply (14), at least two mass storage devices (6;), one of which can optionally be connected to the processor unit (2) via a first data bus (5), and a first trusted platform module (8+) which can be connected to the processor unit (2) via a second data bus (7), characterized by a microcontroller (11) and a switch (21) which can be set by the microcontroller (11) and is connected to the second data bus (7), which connects the processor unit (2) in an operating mode of the data processing system (1) via the second data bus (7) either to the first trusted platform module (8) or to a second trusted platform module (82), wherein the microcontroller (11) is designed to set the changeover switch (21) in a configuration mode of the data processing system (1) according to the mass storage device (6;) selected for the operating mode. 4. Data processing system, comprising a central processor unit (2) which is fed by a power supply (14), at least two mass storage devices (6;), one of which can optionally be connected to the processor unit (2) via a first data bus (5), and a first trusted platform module (8:) which can be connected to the processor unit (2) via a second data bus (7), characterized by a microcontroller (11) which is connected to the second data bus (7) and is designed to emulate both the first trusted platform module (8+) and a second trusted platform module (82) each as a software instance (8;), of which software instances (8;) only one is active in an operating mode of the data processing system (1), wherein the microcontroller (11) is designed to set the active software instance (8;) in a configuration mode of the data processing system (1) according to the mass storage device (6;) selected for the operating mode. 5. Data processing system according to one of claims 1 to 4, characterized in that each mass storage device (6;) is provided with a machine-readable identifier (20) and the microcontroller (11) is connected to a reader (19) for reading identifiers (20) and is designed to detect the mass storage device (6) selected for the operating mode on the basis of the identifier (20) read by the reader (19). 6. Data processing system according to one of claims 1 to 5, characterized in that the configuration mode is alternative to the operating mode. 7. Data processing system according to one of claims 1 to 6, characterized in that in the configuration mode the power supply (14) of the central processor unit (2) is interrupted. 8. Data processing system, comprising a central processing unit (2), at least two mass storage devices (6;), one of which can optionally be connected to the processor unit (2) via a first data bus (5), and a first trusted platform module (8:) which can be connected to the processor unit (2) via a second data bus (7), characterized by a second Trusted Platform module (82) which can optionally be connected to the second data bus (7) instead of the first Trusted Platform module (84), wherein one of the mass storage devices (6;) and one of the trusted platform modules (8;) assigned to this mass storage device (6;) are arranged in a common transport housing (22;) which is detachably connected to the remaining data processing system (23). 9. Data processing system according to one of claims 1 to 8, characterized in that the first data bus (5) is designed according to one of the standards USB, USB-C, Thunderbolt, SATA, eSATA, PCI or PCIe. 10. Data processing system according to one of claims 1 to 9, characterized in that the second data bus (7) is designed according to one of the standards i2C, SPI or LPC. 11. Data processing system according to one of claims 1 to 10, characterized in that each of the mass storage devices (6;) is a semiconductor hard disk or a non-volatile memory chip. Here 3 sheets of drawings