We define and construct a new primitive called a fully homomorphic message authenticator. With such scheme, anybody can perform arbitrary computations over authenticated data and produce a short tag that authenticates the result of the computation (without knowing the secret key). This tag can be verified using the secret key to ensure that the claimed result is indeed the correct output of the...

In a Verifiable Data Streaming (VDS) protocol a computationally weak client outsources his storage to an untrusted storage provider. Later, the client can efficiently append and update data elements in the already outsourced and authenticated data set. Other users can stream arbitrary subsets of the authenticated data and verify their integrity on-the-fly, using the data owner’s public verifica...