Can homomorphic decryption of DES be practical? I was reading this paper Homomorphic evaluation of the AES Circuit by Gentry et al. when I thought if something similar can be done with DES or 3DES, e.g. it is plausible to decrypt DES homomorphically ?
Every algorithm that can be modeled as a Boolean circuit can be homomorphically encrypted. DES/3DES can surely be modeled by a Boolean circuit.

The question is if it is practical to use DES/3DES for homomorphic encryption. I don't think so.