Efficient cryptographic schemes provably as secure as subset sum

Very efficient constructions, based on the intractability of the subset sum problem for certain dimensions, are shown for a pseudorandom generator and for a universal one-way hash function. (Pseudorandom generators can be used for private key encryption, and universal one-way hash functions for signature schemes). The increase in efficiency in the construction is due to the fact that many bits can be generated/hashed with one application of the assumed one-way function. All the constructions can be implemented in NC using an optimal number of processors