Process to secure a personal portable object

A personal portable object comprising:

• a body,
• a microchip,
• a printed image;
• and
• a device enabling the object to communicate with an entity external to the object,
• wherein the object comprises an image feature vector Vsi(num) generated from an image file comprising a stored image and an insertion algorithm, wherein generating the image feature vector Vsi(num) comprises:
• dividing, for each division level of a plurality of division levels, the stored image into sub-images sized according to the division level to obtain a plurality of sub-images corresponding to the plurality of division levels,
• wherein, for each division level, sub-images of the division level comprise a different number of pixels than sub-images of each other division level, and
• wherein, for each division level, at least one sub-image of the division level overlaps at least one sub-image of each other division level,
• selecting, from the plurality of sub-images, a selection of sub-images of the stored image using a pseudo-random sequence, and
• combining data from the selection of sub-images to generate Vsi(num).

A method to make secure a personal portable object comprising a body of the personal portable object, a microchip, a printed image and a device to enable said object to communicate with the outside world, the method comprising:

• generating a secret key and a first image feature vector Vsi(num) from an image file representing said printed image stored in microchip, wherein said step for generating said secret key and said first image feature vector Vsi(num) comprises:
• dividing said image file into sub-images of different n-levels of fineness,
• wherein, for each n-level of fineness, sub-images of the n-level of fineness comprise a different number of pixels than sub-images of each other n-level of fineness, and
• wherein, for each n-level of fineness, at least one sub-image of the n-level of fineness overlaps at least one sub-image of each other n-level of fineness;
• selecting said sub-images from each of said levels using a pseudo-random sequence;
• generating said first feature vector Vsi(num) having a selected feature from each of said selected sub-images;
• generating a digital signature by combining data from a selection of sub-images;
• and
• generating said secret key from information representing a selection of said sub-images, information representing selected features for each sub-image and said digital signature;
• storing said first image feature vector Vsi(num) and said secret key in said microchip;
• comparing a second image feature vector Vsi(dig) with said first image feature vector Vsi(num) using a read-back algorithm to match the first image feature vector Vsi(num) and the second image feature vector Vsi(dig);
• and
• confirming the validity of said object body and said microchip when said second image feature vector Vsi(dig) matches said first image feature vector Vsi(num).