Method, device and medium for protecting against ciphertext physical attack on lattice public key encryption algorithm based on multiple checks

Abstract

The application relates to the field of data security and discloses a ciphertext physical attack protection method and device based on multiple checks and a lattice public key encryption algorithm, and a medium, the method comprising the following steps: in the process of decapsulation, performing decompression processing on input ciphertext, and performing ciphertext integrity checking in the decompression stage; performing decryption operation on the decompressed ciphertext to obtain plaintext messages, and performing Hamming weight checking on the plaintext messages in the decryption stage; performing re-encryption operation using the plaintext messages to generate new ciphertext, and performing ciphertext legality checking in the re-encryption stage; comprehensively judging whether an attack behavior exists according to the results of the ciphertext integrity checking, the Hamming weight checking and the ciphertext legality checking; if the attack behavior exists, triggering a key refreshing mechanism, otherwise, normally outputting a shared key. The application can be applied to various lattice public key encryption schemes using FO transformation, for example, Kyber, the overhead of which is negligible compared with that of a traditional method, and the application has excellent protection effect and low cost advantage.

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