> FIPS-186-3, the document that specifies DSS (aka DSA with some > additional restrictions as to algorithm, key length, etc) specifies 4 > key sizes: Five, but nobody uses DSA-512 and I think it's been formally obsoleted. But yes, DSA-512 is a real thing, although GnuPG never supported it (for good reasons -- it was seen as marginal even when it first came out!).