COMMON RANDOMNESS IN INFORMATION-THEORY AND CRYPTOGRAPHY .1. SECRET SHARING

As the first part of a study of problems involving common randomness a t distant locations, information-theoretic models of secret sharing, i .e., of generating a common random key at two terminals, without letti ng an eavesdropper obtain information about this key, is considered. T he concept of key-capacity is defined. Single-letter formulas of key-c apacity are obtained for several models, and bounds to key-capacity ar e derived also for other models.