There&#x27;s more to it than that, though - a table that could let you directly look up the discrete log of an arbitrary A would require on the order of 2^1024 entries (for a 1024 bit group).<p>It&#x27;s a table specifically of the discrete logs of a large (but tractable) number of small primes.  Those discrete logs can be used as the input to a separate stage that can calculate the discrete log of any value in the field.