A computer system for secure data access control, according to some examples, may perform operations including: receiving first data from a first client associated with a first user; using a first data access agent to store the first data in a first data store, the first data access agent having access to the first data store and not having access to a second data store; receiving second data from a second client associated with a second user; and using a second data access agent to store the second data in the second data store, the second data access agent having access to the second data store and not having access to the first data store.