Input/output module, data processing apparatus and method for checking the operation of a data processing apparatus

Patent metadata

Field	Value
Publication number	US-10002261-B2
Application number	US-201314034703-A
Country	US
Kind code	B2
Filing date	Sep 24, 2013
Priority date	Sep 24, 2012
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

Various embodiments provide an input/output module, including: at least one input/output port for the input of data; a signature generator that is coupled to the input/output port and is set up to generate a signature for the data from the data; a reference input, wherein the reference input is set up for the application of a reference signature; and a comparator that is coupled to the signature generator and to the reference input, and is set up to output an alarm signal if the signature of the data on the input/output port differs from the reference signature.

First claim

What is claimed is:

1. An input/output device configured to verify data prior to input to a processor and/or after output from the processor, comprising:
at least one input/output port configured for input of data from an external source to the processor and/or output of data from the processor to the external source;
an interface device configured to input data received at the at least one input/output port to the processor and further configured to output data from the processor to the at least one input/output port, wherein the interface device is coupled to the input/output port; and
a command signature circuit comprising:
a signature generator circuit that is coupled to the input/output port and is configured to generate a signature for the data from the data prior to input to the processor from the interface device and/or after output from the processor to the interface device; and
a comparator circuit that is coupled to the signature generator circuit and is configured to receive a reference signature, and is further configured to output an alarm signal if the signature of the data on the input/output port differs from the reference signature prior to input to the processor and/or after output from the processor,

wherein the command signature circuit has a first operating state and a second operating state and is configured
to monitor data from a program memory to verify the data on the input/output port after output from the processor in the first operating state, and
to monitor data from the input/output port to verify the data on the input/output port prior to input to the processor in the second operating state.

2. The input/output device of claim 1 ,
wherein the comparator circuit is coupled to a memory that stores the reference signature.

3. The input/output device of claim 1 ,
wherein the comparator circuit is coupled to the processor, wherein the processor calculates the reference signature.

4. The input/output device of claim 1 ,
wherein the reference signature is a signature from data that is permitted to be output on the input/output port.

5. The input/output device of claim 1 ,
wherein the reference signature is a signature from data that is permitted to be handled by a processor.

6. The input/output device of claim 1 ,
wherein the signature of the data and the reference signature are hash values.

7. The input/output device of claim 1 , further comprising:
an input/output memory, wherein the input/output memory is coupled to the input/output port.

8. The input/output device of claim 1 ,
wherein the interface device is one of a group consisting of:
a universal asynchronous receiver transmitter;
a contactless interface;
a contactless interface based on ISO 14443;
an I 2 C bus;
a serial peripheral interface; and
a single wire protocol interface.

9. A data processing apparatus, comprising:
a processor; and
at least one input/output device configured to verify data prior to input to the processor and/or after output from the processor, comprising:
at least one input/output port configured to receive data from an external source and output data to the external source;
an interface device coupled to the input/output port, wherein the interface device is configured to receive data from the at least one input/output port and input the data to the processor and further configured to receive data from the processor and output the data to the at least one input/output port;
a signature generator circuit that is coupled to the input/output port and is configured to generate a signature for the data from the data prior to input to the processor from the interface device and/or after output from the processor to the interface device; and
a comparator circuit that is coupled to the signature generator circuit and is configured to receive a reference signature, and is further configured to output an alarm signal if the signature of the data on the input/output port differs from the reference signature prior to input to the processor and/or after output from the processor;
a command signature circuit, comprising a signature generator circuit and a comparator circuit, wherein the signature generator circuit and the comparator circuit of the input/output device are implemented by the signature generator circuit and the comparator circuit of the command signature circuit;
wherein the command signature circuit has a first operating state and a second operating state and is configured to monitor data from a program memory to verify the data on the input/output port after output from the processor in the first operating state, and to monitor data from the input/output port to verify the data on the input/output port prior to input to the processor in the second operating state; and
wherein the processor is coupled to the at least one input/output device.

10. The data processing apparatus of claim 9 , further comprising:
a card body, wherein the data processing apparatus is arranged in the card body.

11. A method for checking the function of a data processing apparatus, the data processing apparatus comprising a processor and an input/output port, the method comprising:
receiving data at the input/output port, wherein the data is configured to be input to the processor from an external source or output from the processor to the external source;
calculating at least one signature for the data after being output from the processor to the input/output port and/or prior to being input to the processor from the input/output port;
comparing the signature of the data with a reference signature; outputting an alarm signal if the signature of the data differs from the reference signature;
wherein the calculating the signature for data that is output or input on the input/output port and the comparing the signature of the data with a reference signature are performed by a command signature circuit; and
changing the command signature circuit from a first operating state to a second operating state, wherein the command signature circuit is configured to monitor data from a program memory to verify the data on the input/output port after output from the processor in the first operating state and to monitor data from the input/output port to verify the data on the input/output port prior to input to the processor in the second operating state.

12. The method of claim 11 ,
wherein the reference signature is a signature pertaining to data that is permitted to be output via the input/output port.

13. The method of claim 11 ,
wherein the reference signature is a signature pertaining to data that is permitted to be input via the input/output port.

14. The method of claim 11 ,
wherein the reference signature is stored in a memory and is read from the memory for comparing the signature of the data with the reference signature.

15. The method of claim 11 ,
wherein the reference signature is calculated in real time by a processor while data is present on the input/output port.

16. The method of claim 11 ,
wherein the data is output on the input/output port only if the signature of the data matches the reference signature.

17. The method of claim 11 ,
wherein the data is input into the data processing apparatus on the input/output port only if the signature of the data matches the reference signature.

18. The method of claim 11 ,
wherein outputting the alarm signal involves at least one of the following being performed:
terminating outputting data on the input/output port from the data processing apparatus;
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Assignees

• Infineon Technologies Ag

Inventors

• Janke Marcus
• Laackmann Peter

Classifications

• G06F2221/2101

  Auditing as a secondary aspect · CPC title

• G06F21/72

  in cryptographic circuits · CPC title

• H04L9/3247

  involving digital signatures · CPC title

• G06F21/64 Primary

  Protecting data integrity, e.g. using checksums, certificates or signatures · CPC title