A length-invariant hybrid mix

This paper presents a Mix-net that has the following properties: it efficiently handles long plaintexts: that exceed the modulus size of til e underlying public-key encryption scheme as well as ver) short ones (lengt h-flexibility), input ciphertext length is not impacted by the number of mix-servers (lengt h-invariance), and its security in terms of anonymity can be proven ill a formal way (probable security). If desired, one can add robustness so that it outputs correct re suits in t ile presence of corrupt users: and servers. The security is proven in such a sense that breaking the anonymity of our Mixnet is equivalent to breaking the indistinguishability assumption of the underlying symmetric encryption scheme or the Decision Diffie-Hellman assumption.