A Multi-User Key and Data Exchange Protocol to Manage a Secure Database

We propose a multi-user key and data exchange protocol, which is able to manipulate stored encrypted da ta without need to decipher. This protocol can be used by several clients at any given time, which are connected to a server, for keys and data exchanges. The c iphered da ta located in client and that l ocated in the server is exchanged, stored, compared and processed without the need to decipher. To clarify the protocol explanation we use it in a Database Management System (DBMS). The relational algebra operations, which include projection, selection, among others, are ev aluated u sing the c ryptographic protocol on encrypted da ta. Let us s uppose a relation instance Is ciphered and stored on secondary memory. The protocol can evaluate queries s uch a s selection σAi > v(Is) on the e ncrypted stored version. In this s election no data is deciphered on to main o r secondary memory and therefore remains encrypted. Different users can submit queries, thus the protocol must have a strong key management.