David Elliott Bell (born in 1945) is an American mathematician and computer security pioneer.

At the 21st Annual Computer Security Applications Conference in Tucson, Arizona in 2005, Bell presented a look back at the Bell-LaPadula model.

He ran his own consulting company (BBND, Incorporated) before returning to the technical path at Mitretek Systems and EDS.

His constructive result demonstrated how to realize each of the published policies using a single "Universal Lattice Machine."

At the 1994 New Security Paradigms and Workshop (NSPW), Bell presented his paper on "Modeling the 'multi-policy machine' ".