In [[cryptography]], a [[key exchange|public key exchange]] algorithm is a [[cryptographic algorithm]] which allows two parties to create and share a secret key, which they can use to encrypt messages between themselves. The '''[[Ringring Learninglearning with Errorserrors]] Keykey Exchangeexchange''' ('''RLWE-KEX''') is one of a new class of public key exchange algorithms that are designed to be secure against an adversary that possesses a [[quantum computer]]. This is important because the vast majority of [[public key algorithm]]s in use today are easily broken by a quantum computer and scientists are making steady progress toward creating such a computer. [[Ring Learninglearning with Errorserrors|RLWE]]-KEX is one of a set of [[Postpost-quantum cryptography|Post Quantumpost-quantum cryptographic]] algorithms which are based on the difficulty of solving certain mathematical problems involving [[Latticelattice-based cryptography|lattices]]. Unlike older lattice based cryptographic algorithms, the [[Ringring Learninglearning with Errorserrors|RLWE]]-KEX is provably reducible to a known hard problem in lattices.
