The cryptographic community has developed many tools to incorporate distributed trust mechanisms into cryptographic primitives and protocols as well as primitives where parties are naturally distributed. Since the fastest growing paradigm in computing is distributed systems and communication networks, the importance of distributed mechanisms has been increasing, and will likely to be pervasive in the future. Here, we review the various distributed mechanisms that have been developed and applied to achieve distributed public key cryptosystem. We focus primarily on the more efficient threshold cryptographic schemes (based on sharing public-key functions) and exemplify (only) some of the issues regarding these systems.