Method and device for carrying out k anonymity updating on encrypted inverted index table
An inverted index table, unencrypted technology, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve the problems affecting the purpose of confidentiality, exacerbation, etc.
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no. 1 example
[0061]With respect to the first embodiment, for a given security parameter k, when the size of the row set (=n) is set to n≥k, a curious but honest attacker identifies the target row from the updated row set RS The probability is at most 1 / k, where n and k are positive integers.
[0062] Fig. 4 and Fig. 5 are schematic diagrams explaining the k anonymous update method and device according to the first embodiment of the present invention. FIG. 4 shows a block diagram in the case of addition, and FIG. 5 shows a block diagram in the case of deletion.
[0063] AIM in the first embodiment
[0064] Adds a dummy data item to each of the other n-1 dummy rows while adding a new data item to the target row. Therefore, the length of all n lines is increased by 1, although the encrypted data in all n lines has changed.
[0065] For the case of adding a new data item in the first embodiment, various components are described below in conjunction with FIG. 4 .
[0066] (1) The RS obtai...
no. 2 example
[0091] In the case of adding a new data item, in the first embodiment, n-1 dummy data items will be added; in the case of deleting an encrypted data item, in the first embodiment, a dummy data item will be added . To improve space efficiency, fewer dummy data items should be introduced while maintaining the same security strength.
[0092] In the second embodiment, in order to satisfy that for a given security parameter k, the probability of a curious but honest attacker identifying a target row from an updated RS is at most 1 / k, for addition, the size of RS (=n) set to And for deletion, the size of RS is set to n≧k. Here, n and k are positive integers, e is a mathematical constant (also known as "Euler's constant", e≈2.71828), is the rounding up function, Indicates the smallest integer greater than or equal to X.
[0093] Fig. 7 and Fig. 8 are schematic diagrams explaining the k anonymous update method and device according to the second embodiment of the present inven...
no. 3 example
[0121] In the second embodiment, the number of dummy data items remains constant whether a new data item is added or an encrypted data item is deleted. Space efficiency can be further improved if certain conditions are met. The key idea of the third embodiment is the same as that of the second embodiment except for the following additional adjustment process.
[0122] adjustment process
[0123] It is assumed that s is the common number of dummy data items in all current n rows, that is, each row contains at least s dummy data items. If s-1 ≥ 1 and the current length of each row is at least s+1, remove s-1 dummy data items from each row.
[0124] After the adjustment process, the probability that each row still satisfies that the row is the target row is at most 1 / k.
[0125] Fig. 10 and Fig. 11 are schematic diagrams explaining the method and apparatus for k anonymous update according to the third embodiment of the present invention. FIG. 10 shows a block diagram in t...
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