 This approach permitted nodes to agree upon shared key material even if they were implemented via two incompatible technologies; for example, a node based on phase-modulation through fiber could exchange keys with one based on polarization-modulation through the atmosphere.In fact, it even permitted transmitters to share key material with other (compatible or incompatible) transmitters.Furthermore, the raw key material could be routed by multiple "striped" paths through the network (e.g.