Abstract: Aiming at the problem of the security of sensitive information, we designed a probabilistic multivariate public key cryptosystem based on ordered sequences. The sequence of plaintext and disturbance information remained unchanged in the new plaintext. However, the position of each item of the new plaintext was random. In the process of decryption, we needed the same two sets of new plaintext for comparison, and found out the corresponding relation in each item, in which the original plaintext could be obtained. The public key cryptosystem based on onetime pad has good randomness, so it has higher safety.

Key words: ordered sequence, onetime pad, multivariate public key cryptography, sensitive information