Abstract: In order to resist the quantum attack on users information, on the basis of existing probabilistic cryptosystem, we introduced the idea of probability into multivariate public key cryptosystem and gave a new public key cryptosystem, namely probabilistic multivariate public key cryptography based on unordered sequences. With this method, the sequence of plaintext message was changeless,   the disturbance information was out of order, and the positions of
 them in the constructed plaintext were random. The collision of plaintext message and disturbance information existed in the process of decryption, so recovery of plaintext message might be itself or its subsequence. Both sides of communication should be agreed upon the length of the subsequence of plaintext message in advance when using the public key cryptography. If the contracted number was consistent with the length of the subsequence, the decryption was considered successful.

Key words: disturbance information, multivariate public key cryptography, encryption algorithm