for all keys in hash-1, where k-1 is current key
  for all keys in hash-2, where k-2 is current key
    put k-1 in store if k-1 = k-2
  end-for
end-for

#  "store" would have all the common keys in the end

##</code><code>##

common set to false
for all keys in hash-1, where k-1 is current key
  for all keys in hash-2, where k-2 is current key
    if k-1 = k-2,
      common set to true
      break out of both loops
  end-for
end-for

# test common to check for commonality