Professor Zhou received B.E. from Department of Automation, Beijing University of Technology in Jan.1982. He received postgraduate graduation diploma from Department of Computer Science, Beijing University of Technology in 1987. He was a lecturer in Department of Computer Science, Beijing University of Technology from 1987 to 1992, an associate professor in College of Information, Beijing Union University from 1992 to 2005, a professor in Institute of Information Technology, College of Information, Beijing Union University from 2005 to 2012, a professor emeritus in College of Smart City, Beijing Union University since 2012. He constructs mutually-inversistic logic and applies it to the fields of computer science and artificial intelligence, such as automated theorem proving, logic programming, planning and scheduling, expert systems, semantic network, program verification, natural language understanding, hardware verification, machine learning, data mining, uncertainty reasoning, program refinement, many-valued computer, etc. He published about 80 refereed papers, authored 4 monographs on them. He was a senior member of China Computer Federation, a supervisor of Beijing Logical Association before his retirement.    

Multi-level random dynamic secret key algorithm Non-replicable function-based multi-level random dynamic secret key algorithm XM-1 is constructed by Ming Xian. y=(ax)mod m                     (1) We call formula (1) as the least non-negative residual function. Here, y is the least non-negative residue of the product of a and x modular m. (Corresponding to Python statement y=(a * x) % m). When the parameters a and m are given, then for every x there necessarily exists a unique y corresponding to it. Therefore, y is a function of x. XM-1 use the least non-negative residual functions for encryption and decryption. y1=(a1x)mod m1,…, yn=(anyn-1)mod mn         (2)     Formula (2) are the the n-level encryption functions, where, a1, …an and m1…, mn are the encryption keys. And (ai, mi)=1（1≤i≤n），m1＜…＜ mn。 From plain text x performing formula (2) from left to right we can obtain cipher text yn. x=(a1-1y1)mod m1,…, yn-1=(an-1yn)mod mn        (3) Formula (3) are the n-level decryption functions, where, a1-1, …an-1 and  m1…, mn are the decryption keys. And ai ai-1≡1（mod mi）（1≤i≤n）. From cipher text yn performing formula (3) from right to left we can obtain plain text x. Formulas (2) and (3) can be abbreviated to formulas (4) and (5): (a1, m1) ,      …,  (an, mn)                  （4） (a1-1, m1) ,   …,  (an-1, mn)                （5） For example,             (61,93)，(13,155)，(25,231)              （6） (61,93)，(12,155)，(37,231)              （7） is a simple 3-level encryption-decryption system. From plain text 23 performing formula (6) from left to right we can finally obtain cipher text 59. 1.     From 23 and (61,93) we obtain (61×23)mod 93=8. 2.     From 8 and (13,155) we obtain (13×8)mod 155=104. 3.     From 104 and (25,231) we obtain (25×104)mod 231=59. That is, the cipher text is 59. From cipher text 59 performing formula (7) from right to left we can obtain plain text 23. 1.      From 59 and (37,231) we obtain (37×59)mod 231=104  2.      From 104 and (12,155) we obtain  (12×104)mod 155=8. 3.      From 8 and (61,93) we obtain (61×8)mod 93=23. That is, the plain text is 23. XM-1 has the following advantages: 1.      Under the circumstances that no secret key is exchanged between the sender and the receiver, every encryption uses the new encryption secret keys and every decryption uses the new decryption secret keys. 2.      The number of secret keys is randomized. 3.       Secret keys are randomized. 4.      When the system is not run, there is no secret key. These advantages make XM-1 not decipherable.   XM-1 has been implemented on computers. Input plain text “鲜明的密码系统” into one computer. The encryption system changes it into cipher text. For one plain text, more cipher texts can be produced. In this example two cipher texts are produced. See Fig. 1.       Fig. 1 The cipher texts are transmitted to another computer. The decryption system translates them back to plain text  “鲜明的密码系统”. See Fig. 2.   Fig. 2 Even if other people obtain the cipher text, they cannot translate it into plain text without the decryption system. Special reminder: If you’d like to use this patent, please contact the first author Ming Xian (The inventor of this patent) and Xunwei Zhou.