The method, program and information processing system secures data, and particularly security sensitive words, characters or data objects in the data, in a computer system with multiple independent levels of security (MILS). Each level of MILS has a computer sub-network with networked workstations. The MILS sub-networks are connected together via security guard computer(s) and each guard computer has separate memories for each level (TS, S, C, UC (or remainder)). The method extracts the security sensitive words/data (a granular action), from the source document for each MILS level, stores the extracted data in a corresponding extract store for each level and permits reconstruction/reassembly of the dispersed data via said extracted data at each said level of said multiple security levels and remainder data only in the presence of a predetermined security clearance commensurate with each MILS level.