Ekert protocol (E91)

The Ekert protocol (E91) is a method for secure communication using quantum physics. It relies on pairs of entangled particles, which are linked so that measuring one instantly determines the state of the other, no matter how far apart they are. By sharing these entangled particles and measuring their properties in different ways, two parties can detect any eavesdropping, because tampering would disturb the quantum states. This ensures the communication remains secure, as any interception attempt reveals itself through changes in the measurements, making the protocol highly robust for confidential information exchange.