…Entanglement starts with a beam of light shot into a crystal. This prism splits the light into pairs of photons with strangely linked behaviour. Manipulate one particle in a pair, and its partner will instantly react. Measure the first one’s polarisation, for example, and entanglement could ensure that its twin will have the opposite polarisation when measured.
These entangled photons can theoretically be used to set up a secure communication line between two people, with privacy guaranteed by the laws of physics..
read more at https://www.newscientist.com/article/2144866-first-underwater-entanglement-could-lead-to-unhackable-comms/?utm_term=Autofeed&utm_campaign=Echobox&utm_medium=Social&cmpid=SOC|NSNS|2017-Echobox&utm_source=Twitter#link_time=1503505627