A system to improve communication security in cluster machine processing may include interconnected computers that can jointly process data. The system may also include a shared secret key used by each of the interconnected computers to encrypt, decrypt, and/or authenticate data being sent, or received, from one of the interconnected computers to another of the interconnected computers. The system may further include a new shared secret key used by each of the interconnected computers to encrypt, decrypt, and/or authenticate data being sent, or received, from one of the interconnected computers to another of the interconnected computers. In addition, the new shared secret key may coexist with the shared secret key without adversely affecting the joint processing of data performed by the plurality of interconnected computers.