Secrecy Group Creation with Symmetric-Key Cryptography

We lift Cardelli, Ghelli and Gordon’s secrecy group creation operator [1] to a relative of the spicalculus that supports symmetric key cryptography, and show a natural extension of the associated type system. We then formulate a notion of secrecy preservation in the presence of cryptography, and prove that well-typed processes in the extended type system preserve secrecy of declared secrets, even in the presence of untyped opponents.