Confidentiality enhancement method and device based on multi-linear modulus hash function

The invention discloses a confidentiality enhancement method based on a multi-linear modulus hash function, solves the problem that the calculated amount of existing confidentiality enhancement is quickly increased along with the increase of the key processing length, and belongs to the field of quantum key distribution. The method comprises the following steps: S1, two communication parties obtain a shared consistent low-security key S; S2, one of the two communication parties randomly selects a multi-linear modulus hash function gx from the multi-linear modulus hash function family MMH * and shares the multi-linear modulus hash function gx to the other party, and the two communication parties use the multi-linear modulus hash function gx to compress the shared consistent low-security key S to obtain a consistent intermediate key S '= gx (S); and S3, one of the two communication parties randomly selects modular arithmetic hash functions hc, d from the modular arithmetic hash function family MH * and shares t