Quantum secret sharing

Secret sharing is a procedure for splitting a message into several parts so\nthat no subset of parts is sufficient to read the message, but the entire set\nis. We show how this procedure can be implemented using GHZ states. In the\nquantum case the presence of an eavesdropper will introduce errors so that his\npresence can be detected. We also show how GHZ states can be used to split\nquantum information into two parts so that both parts are necessary to\nreconstruct the original qubit.\n