<P> Secure Sockets Layer (SSL) uses Diffie--Hellman key exchange if the client does not have a public - private key pair and a published certificate in the Public Key Infrastructure, and Public Key Cryptography if the user does have both the keys and the credential . </P> <P> Key distribution is an important issue in wireless sensor network (WSN) design . There are many key distribution schemes in the literature that are designed to maintain an easy and at the same time secure communication among sensor nodes . The most accepted method of key distribution in WSNs is key predistribution, where secret keys are placed in sensor nodes before deployment . When the nodes are deployed over the target area, the secret keys are used to create the network . For more info see: key distribution in wireless sensor networks . </P> <P> Key distribution and key storage are more problematic in the cloud due to the transitory nature of the agents on it . Secret sharing can be used to store keys at many different servers on the cloud . In secret sharing, a secret is used as a seed to generate a number of distinct secrets, and the pieces are distributed so that some subset of the recipients can jointly authenticate themselves and use the secret information without learning what it is . But rather than store files on different servers, the key is parceled out and its secret shares stored at multiple locations in a manner that a subset of the shares can regenerate the key . </P> <P> Secret sharing is used in cases where one wishes to distribute a secret among N shares so that M <N of them (M of N) can regenerate the original secret, but no smaller group up to M − 1 can do so . </P>

Various techniques for the distribution of public keys