Solid-state imaging device, method for driving solid-state imaging device, and electronic apparatus
A solid-state imaging device having a pixel portion in which a plurality of pixels each including a photodiode are arranged in rows and columns, a reading part for reading pixel signals from the pixel portion, and a key generation part which generates a unique key by using, as the key generation-use data, at least one of fluctuation information of pixels and fluctuation information of the reading part, wherein the key generation part includes a tamper resistance enhancement processing part for processing the key generation-use data to enhance the tamper resistance making it difficult to break the unique key as tamper resistance enhancement processing. Due to this, a unique key having a high confidentiality can be generated. Further, reproducibility and uniqueness of the unique ID can be improved to secure a high tamper resistance of the unique key, and tampering and forgery of an image can be reliably prevented.
1. A solid-state imaging device comprising
A pixel portion in which a plurality of pixels each including a photodiode are arranged in rows and columns,
a reading part for reading pixel signals from the pixel portion, and
a key generation part which generates a unique key by using, as key generation-use data, at least one of fluctuation information of the pixels and fluctuation information of the reading part, wherein
the key generation part includes a tamper resistance enhancement processing part for processing the key generation-use data to enhance the tamper resistance for making the unique key difficult to break as tamper resistance enhancement processing.
2. The solid-state imaging device as set forth in claim 1 , wherein the tamper resistance enhancement processing part in the key generation part
includes a decorrelation processing part for performing decorrelation processing with respect to the key generation-use data for acquiring decorrelated data weakened in correlation from intercepted data correlated with the key generation-use data and
generates the unique key by using the acquired decorrelated data.
3. The solid-state imaging device as set forth in claim 2 , wherein the data obtained by processing the intercepted data in the decorrelation processing part is not correlated with the decorrelated data.
4. The solid-state imaging device as set forth in claim 2 , wherein:
the key generation-use data is generated related to a pixel signal read out by the reading part, is data not correlated with the intercepted data when extracting a pixel with a value showing correlation within s first range, and is data correlated with the intercepted data when extracting a pixel in a second range outside of the first range, and
the decorrelation processing part includes a filter for extracting from the key generation-use data, as the decorrelated data, only pixel data with values showing correlation falling in the first range.
5. The solid-state imaging device as set forth in claim 1 , wherein the tamper resistance enhancement processing part in the key generation part includes an averaging processing part for performing averaging processing on a plurality of pixels of the key generation-use data.
6. The solid-state imaging device as set forth in claim 5 , wherein the tamper resistance enhancement processing part in the key generation part includes a judgment part for judging magnitude between two adjacent pixels and binarizing the data in the data subjected to the averaging processing in the averaging processing part.
7. The solid-state imaging device as set forth in claim 6 , wherein the tamper resistance enhancement processing part in the key generation part includes a compression part for compressing the output data of the judgment part.
8. The solid-state imaging device as set forth in claim 6 , wherein the tamper resistance enhancement processing part in the key generation part includes a sorting part for sorting the output data of the judgment part.
9. The solid-state imaging device as set forth in claim 1 , wherein the key generation part uses a leak current and position information as the fluctuation information of the pixels.
10. The solid-state imaging device as set forth in claim 1 , wherein a pixel includes
a photo-electric conversion element for accumulating a charge generated by photo-electric conversion in an accumulation period,
a transfer element capable of transferring the charge accumulated in the photo-electric conversion element in a transfer period,
a floating diffusion to which the charge accumulated in the photo-electric conversion element is transferred through the transfer element,
a source-follower element for converting the charge in the floating diffusion with a gain in accordance with the charge amount, and
a reset element for resetting the floating diffusion to a predetermined potential.
11. The solid-state imaging device as set forth in claim 5 , wherein the pixel portion has a pixel sharing structure sharing one floating diffusion, one source-follower element, and one reset element among a plurality of photo-electric conversion elements and transfer elements.
12. The solid-state imaging device as set forth in claim 11 , wherein a clip circuit for restricting the pixel output voltage amplitude is arranged at the end of the pixel array.
13. A method for driving a solid-state imaging device including a pixel portion in which a plurality of pixels each including a photodiode are arranged in a matrix and a reading part for reading pixel signals from the pixel portion, comprising
an information acquisition step of acquiring at least one information of fluctuation information of the pixels and fluctuation information of the reading part and
a key generation step of generating a unique key by using the fluctuation information acquired in the information acquisition step as key generation-use data and,
in the key generation step, processing the key generation-use data for enhancing the tamper resistance for making the unique key difficult to break as tamper resistance enhancement processing.
14. The method for driving the solid-state imaging device as set forth in claim 13 , wherein the tamper resistance enhancement processing in the key generation step
performs decorrelation processing with respect to the key generation-use data for acquiring decorrelated data weakened in correlation from intercepted data correlated with the key generation-use data and
generates the unique key by using the acquired decorrelated data.
15. The method for driving the solid-state imaging device as set forth in claim 13 , wherein the tamper resistance enhancement processing in the key generation step
performs averaging processing between two pixels which are adjacent in the reading direction of the key generation-use data and
judges magnitude between the two adjacent pixels to binarize the data in the data subjected to the averaging processing.
16. An electronic apparatus comprising
a solid-state imaging device and
an optical system for forming a subject image in the solid-state imaging device, wherein
the solid-state imaging device has
a pixel portion in which a plurality of pixels each including a photodiode are arranged in a matrix,
a reading part for reading pixel signals from the pixel portion, and
a key generation part which generates a unique key by using, as key generation-use data, at least one of fluctuation information of the pixels and fluctuation information of the reading part, and
the key generation part includes a tamper resistance enhancement processing part for processing the key generation-use data to enhance the tamper resistance for making the unique key difficult to break as tamper resistance enhancement processing.