This document specifies digital signature mechanisms with appendix whose security is based on the discrete logarithm problem. This document provides — a general description of a digital signature with appendix mechanism, and — a variety of mechanisms that provide digital signatures with appendix. For each mechanism, this document specifies — the process of generating a pair of keys, — the process of producing signatures, and — the process of verifying signatures. Annex A defines object identifiers assigned to the digital signature mechanisms specified in this document, and defines algorithm parameter structures. Annex B defines conversion functions of FE2I, I2FE, FE2BS, BS2I, I2BS, I2OS and OS2I used in this document. Annex D defines how to generate DSA domain parameters.