diff --git a/leaderboard.lua b/leaderboard.lua
index 4ceb83e..bc633b5 100644
--- a/leaderboard.lua
+++ b/leaderboard.lua
@@ -35,7 +35,7 @@ local StatTrack = false
 
 local UNCLAIMED = "Unclaimed Record"
 local HELP_MESSAGE = "\x89Leaderboard Commands:\nretry exit findmap changelevel spba_clearcheats lb_gui rival scroll encore"
-local FILENAME = "leaderboard.txt"
+local FILENAME = "leaderboard"
 
 -- Retry / changelevel map
 local nextMap = nil
@@ -150,15 +150,36 @@ local cv_interrupt = CV_RegisterVar({
 	end
 })
 
+local function djb2(message)
+	local digest = 5381
+	for c in message:gmatch(".") do
+		digest = (($ << 5) + $) + string.byte(c)
+	end
+
+	return digest
+end
+
+local function mapChecksum(mapnum)
+	local mh = mapheaderinfo[mapnum]
+	if not mh then
+		return nil
+	end
+
+	local digest = string.format("%04x", djb2(mh.lvlttl+mh.subttl+mh.zonttl))
+	return string.sub(digest, #digest - 3)
+end
+
 local function setST(t, map, flags, scoreTable)
 	local mode = flags & ST_SEP
+	local cks = mapChecksum(map)
 	t[mode] = t[mode] or {}
-	t[mode][map] = scoreTable
+	t[mode][tostring(map)..(cks or "")] = scoreTable
 end
 
 local function getST(t, map, flags)
 	local mode = flags & ST_SEP
-	return t[mode] and t[mode][map] or nil
+	local cks = mapChecksum(map)
+	return t[mode] and t[mode][tostring(map)..(cks or "")] or nil
 end
 
 local function setScoreTable(map, flags, scoreTable)
@@ -222,7 +243,7 @@ local cv_spb_separate = CV_RegisterVar({
 	end
 })
 
-local function score_t(map, name, skin, color, time, splits, flags, stat)
+local function score_t(map, name, skin, color, time, splits, flags, stat, checksum)
 	return {
 		["map"]    = map,
 		["name"]   = name,
@@ -231,7 +252,8 @@ local function score_t(map, name, skin, color, time, splits, flags, stat)
 		["time"]   = time,
 		["splits"] = splits,
 		["flags"]  = flags,
-		["stat"] = stat
+		["stat"] = stat,
+		["checksum"] = checksum
 	}
 end
 
@@ -253,12 +275,47 @@ local function stat_str(stat)
 	return "0"
 end
 
+local function writeScore(fh, score)
+	fh:write(
+		score["map"], "\t",
+		score["name"], "\t",
+		score["skin"], "\t",
+		score["color"], "\t",
+		score["time"], "\t",
+		table.concat(score["splits"], " "), "\t",
+		score["flags"], "\t",
+		stat_str(score["stat"]), "\t",
+		score["checksum"], "\n"
+	)
+end
+
+local function saveScores()
+	local f = assert(io.open(FILENAME + ".txt", "w"))
+	if f == nil then
+		print("Failed to open file for writing: " + FILENAME + ".txt")
+		return
+	end
+
+	for _, tbl in pairs(lb) do
+		for _, scoreTable in pairs(tbl) do
+			for _, score in ipairs(scoreTable) do
+				writeScore(f, score)
+			end
+		end
+	end
+
+	f:close()
+end
+
 -- Read the leaderboard
-local f = io.open(FILENAME, "r")
+local f = io.open(FILENAME + ".txt", "r")
 if f then
+	-- track if scores checksums have been written
+	local checksumWrite = false
+
 	for l in f:lines() do
 		-- Leaderboard is stored in the following tab separated format
-		-- mapnum, name, skin, color, time, splits, flags, stat
+		-- mapnum, name, skin, color, time, splits, flags, stat, map_checksum
 		local t = {}
 		for word in (l+"\t"):gmatch("(.-)\t") do
 			table.insert(t, word)
@@ -287,17 +344,41 @@ if f then
 			end
 		end
 
+		local mapnum = tonumber(t[1])
+
+		-- Checksums
+		local cks = t[9] 
+
+		if cks == nil then
+			checksumWrite = true
+			cks = mapChecksum(mapnum)
+
+			-- We have no previous recognition of this map
+			-- remove it
+			if cks == nil then
+				local rsfh = io.open(FILENAME + "_removed_scores.txt", "a")
+				if not rsfh then
+					print("Failed to open file: ", FILENAME + "_removed_scores.txt")
+					continue
+				end
+				rsfh:write(l, "\n")
+				rsfh:close()
+				continue
+			end
+		end
+
 		table.insert(
 			scoreTable,
 			score_t(
-				tonumber(t[1]),
+				mapnum,
 				t[2],
 				t[3],
 				t[4],
 				tonumber(t[5]),
 				spl,
 				flags,
-				stats
+				stats,
+				cks
 			)
 		)
 
@@ -306,8 +387,13 @@ if f then
 
 	sortScores()
 	f:close()
+
+	-- save scores
+	if checksumWrite then
+		saveScores()
+	end
 else
-	print("Failed to open file: ", FILENAME)
+	print("Failed to open file: ", FILENAME + ".txt")
 end
 
 function allowJoin(v)
@@ -1129,7 +1215,8 @@ local function saveTime(player)
 		timeFinished,
 		splits,
 		Flags,
-		stat_t(player.HMRs or pskin.kartspeed, player.HMRw or pskin.kartweight)
+		stat_t(player.HMRs or pskin.kartspeed, player.HMRw or pskin.kartweight),
+		mapChecksum(gamemap)
 	)
 
 	-- Check if you beat your previous best
@@ -1174,30 +1261,7 @@ local function saveTime(player)
 		StatTrack = true
 	end
 
-	local f = assert(io.open(FILENAME, "w"))
-	if f == nil then
-		print("Failed to open file for writing: " + FILENAME)
-		return
-	end
-
-	for _, tbl in pairs(lb) do
-		for _, scoreTable in pairs(tbl) do
-			for _, score in ipairs(scoreTable) do
-				f:write(
-					score["map"], "\t",
-					score["name"], "\t",
-					score["skin"], "\t",
-					score["color"], "\t",
-					score["time"], "\t",
-					table.concat(score["splits"], " "), "\t",
-					score["flags"], "\t",
-					stat_str(score["stat"]), "\n"
-				)
-			end
-		end
-	end
-
-	f:close()
+	saveScores()
 end
 
 -- DEBUGGING