Privacy-preserving evidence in ALPR applications
First Claim
1. A method for preserving privacy of evidence comprising:
- receiving an encrypted first image which has been generated by encrypting a first image with a symmetric cryptographic key that is generated by encrypting, with a one way function, first information extracted from the first image and first metadata associated with the first image and signing the encrypted first information and first metadata with a shared key, wherein the first metadata comprises a first time;
establishing a link between a second image and the first image comprising comparing a first visual signature computed based on the first image with a second visual signature computed based on the second image, each of the first and second visual signatures being a statistical representation of pixels of the respective image;
when the visual signatures are found to match, receiving the first metadata;
extracting second information from the second image;
reconstructing the symmetric cryptographic key that was used to encrypt the first image based on the second information extracted from the second image and the first metadata, by encrypting, with the one way function, the second information and the first metadata and signing the encrypted second information and first metadata with the shared key, the reconstructed symmetric cryptographic key permitting the first encrypted image to be decrypted to regenerate the first image,wherein at least one of the establishing a link between a second image and the first image and the reconstructing of the symmetric cryptographic key is performed with a processor.
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Accused Products
Abstract
A system and method for preserving privacy of evidence are provided. In the method, an encrypted first image is generated by encrypting a first image acquired at a first location with a symmetric cryptographic key that is based on first information such as a license plate number extracted from the first image and first metadata associated with the first image, such as a time at which the first image was acquired. When a link is established between a second image and the first image, for example, through visual signature matching, the symmetric cryptographic key can be reconstructed, without having access to the first image, but based instead on the first metadata and information extracted from the second image. The reconstructed symmetric cryptographic key can then be used for decryption of the encrypted image to establish evidence that the license plate number was indeed extracted from the first image.
54 Citations
17 Claims
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1. A method for preserving privacy of evidence comprising:
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receiving an encrypted first image which has been generated by encrypting a first image with a symmetric cryptographic key that is generated by encrypting, with a one way function, first information extracted from the first image and first metadata associated with the first image and signing the encrypted first information and first metadata with a shared key, wherein the first metadata comprises a first time; establishing a link between a second image and the first image comprising comparing a first visual signature computed based on the first image with a second visual signature computed based on the second image, each of the first and second visual signatures being a statistical representation of pixels of the respective image; when the visual signatures are found to match, receiving the first metadata; extracting second information from the second image; reconstructing the symmetric cryptographic key that was used to encrypt the first image based on the second information extracted from the second image and the first metadata, by encrypting, with the one way function, the second information and the first metadata and signing the encrypted second information and first metadata with the shared key, the reconstructed symmetric cryptographic key permitting the first encrypted image to be decrypted to regenerate the first image, wherein at least one of the establishing a link between a second image and the first image and the reconstructing of the symmetric cryptographic key is performed with a processor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 16)
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13. A system comprising:
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memory which receives; an encrypted first image which has been generated by encrypting a first image with a symmetric cryptographic key that is generated by encrypting, with a one way function, first identifier information extracted from the first image and first metadata associated with the first image and signing the encrypted first information and first metadata with a shared key, the first metadata, and a first visual signature which has been extracted from the first image, the first visual signature being a statistical representation of pixels of the first image; a signature matching component which compares the first visual signature with a second visual signature extracted from a second image to establish a link between the second image and the first image, the second visual signature being a statistical representation of pixels of the second image; an identifier recognition component which extracts second identifier information from the second image; a cryptographic key reconstruction component for reconstructing the symmetric cryptographic key that was used to encrypt the first image based on the second identifier information extracted from the second image and the first metadata, by encrypting, with the one way function, the second information and the first metadata and signing the encrypted second information and first metadata with the shared key, the reconstructed symmetric cryptographic key permitting the first encrypted image to be decrypted to regenerate the first image; and at least one processor which implements the signature matching component, identifier recognition component, and cryptographic key reconstruction component. - View Dependent Claims (14, 15)
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17. A computer program product comprising a non-transitory memory storing instructions, which when implemented by a computer processor, perform a method for preserving privacy of evidence comprising:
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receiving an encrypted first image which has been generated by encrypting a first image with a symmetric cryptographic key that is generated by encrypting, with a one way function, first information extracted from the first image and first metadata associated with the first image and signing the encrypted first information and first metadata with a shared key, wherein the first metadata comprises a first time; establishing a link between a second image and the first image comprising comparing a first visual signature computed based on the first image with a second visual signature computed based on the second image, each of the first and second visual signatures being a statistical representation of pixels of the respective image; when the visual signatures are found to match, receiving the first metadata; extracting second information from the second image; and reconstructing the symmetric cryptographic key that was used to encrypt the first image based on the second information extracted from the second image and the first metadata, by encrypting, with the one way function, the second information and the first metadata and signing the encrypted second information and first metadata with the shared key, the reconstructed symmetric cryptographic key permitting the first encrypted image to be decrypted to regenerate the first image.
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Specification