1. A system for recognizing speech securely, comprising: a client configured to provide securely speech in a form of an observation sequence of symbols; a server configured to provide securely a plurality of trained hidden Markov models (HMMs), each trained HMM including a plurality of states, a state transition probability distribution and an initial state distribution, and each state including a subset of the observation symbols and an observation symbol probability distribution, and in which the observation symbol probability distributions are modeled by mixtures of Gaussian distributions; means to determine securely, for each HMM, a likelihood the observation sequence is produced by the states of the HMM; and means to determine securely a particular symbol with a maximum likelihood of a particular subset of the symbols corresponding to the speech,