Batch ciphertext equivalence test method and device

The invention provides a batch ciphertext equivalence test method and device. The method comprises the following steps: acquiring batch ciphertexts and all trap doors corresponding to the batch ciphertexts; the trap door of each ciphertext is used for testing the corresponding ciphertext, and the commitment of the corresponding ciphertext is obtained; determining whether the ciphertext sent by the sender is an invalid ciphertext or not according to the commitments of all the ciphertexts, so as to complete the verification of the ciphertext; under the condition that the ciphertext of the sender is an effective ciphertext, a tester constructs a new Lagrange polynomial according to the polynomial random point corresponding to each ciphertext in the batch of ciphertexts, and determines a secret value of the new Lagrange polynomial; and judging whether the secret value is equal to the secret values of the Lagrange polynomials corresponding to all the ciphertexts, and if so, determining that the plaintexts correspo