Abstract: A method for preventing counterfeiting of an object includes capturing an image of at least a portion of the object that is at least partially transparent. The captured image includes features of the internal structure of the object. Based on the image, a code is generated that encodes features of the internal structure of the object. The code is recorded. Generating the code includes applying a filter to the image to obtain a filtered image, and processing the filtered image to obtain a binary code. A random key, k, is generated, and a codeword fp is obtained by applying an error-correction encoding scheme, ErrorCC, to the random key according to fp=ErrorCC(k), wherein fp has the same size as the binary code fa. An encrypted binary code, r, is computed according r=fa?fp, where ? denotes modulo-2 addition. A hash value, h, is computed according to h=H(k), where H is a one-way hash function. Recording the code comprises recording the encrypted binary code r and the hash value h.

Abstract: A method for preventing counterfeiting of an object includes capturing an image of at least a portion of the object that is at least partially transparent. The captured image includes features of the internal structure of the object. Based on the image, a code is generated that encodes features of the internal structure of the object. The code is recorded. Generating the code includes applying a filter to the image to obtain a filtered image, and processing the filtered image to obtain a binary code. A random key, k, is generated, and a codeword fp is obtained by applying an error-correction encoding scheme, ErrorCC, to the random key according to fp=ErrorCC(k), wherein fp has the same size as the binary code fa. An encrypted binary code, r, is computed according r=fa?fp, where ? denotes modulo-2 addition. A hash value, h, is computed according to h=H(k), where H is a one-way hash function. Recording the code comprises recording the encrypted binary code r and the hash value h.

Abstract: A method for preventing counterfeiting of an object (e.g. paper) is described. The method comprises capturing an image of at least a portion of the object, wherein the portion of the object whose image is captured is at least partially transparent, and wherein the captured image includes features of the internal structure of the object (e.g. the texture of the paper resulting from the arrangement of fibres from which the paper is made). The method further comprises generating, based on the image, a code that encodes features of the internal structure of the object, and recording the code. Generating the code may comprise applying a filter to the image to obtain a filtered image, and processing the filtered image to obtain a binary code. The filter may be a Gabor filter, and processing the filtered image may comprise applying a Gray code to the filtered image. The method may further comprise encrypting the binary code, and recording the code may comprise recording the encrypted binary code.

Abstract: A method for preventing counterfeiting of an object (e.g. paper) is described. The method comprises capturing an image of at least a portion of the object, wherein the portion of the object whose image is captured is at least partially transparent, and wherein the captured image includes features of the internal structure of the object (e.g. the texture of the paper resulting from the arrangement of fibres from which the paper is made). The method further comprises generating, based on the image, a code that encodes features of the internal structure of the object, and recording the code. Generating the code may comprise applying a filter to the image to obtain a filtered image, and processing the filtered image to obtain a binary code. The filter may be a Gabor filter, and processing the filtered image may comprise applying a Gray code to the filtered image. The method may further comprise encrypting the binary code, and recording the code may comprise recording the encrypted binary code.