In this second of a series of papers, we present optical architectures for the encryption of signals or imagery that are defined over discrete domains. As in Part 1, we emphasize the mapping of candidate algorithms and describe encryption transforms in terms of image algebra (IA) expressions, as well as notation specific to this study. both of which were reviewed in Part 1. The feasibility of our algorithms is verified by presenting schematic optical architectures that implement the corresponding IA expressions, together with pertinent analyses. In particular, we discuss the optical implementation of data encryption via mono- and polyalphabetic substitutions, transpositional and polygraphic ciphers, vector quantization, and DES (data encryption standard). Analyses and discussion emphasize computation cost inclusive of propagation time, as well as the information loss expected from physical devices such as spatial light modulators and beam deflectors.