diff -r 6042c938e369 -r 82ad158714e5 libs/hashes.lua
--- a/libs/hashes.lua	Sat Jan 09 11:03:30 2016 +0000
+++ b/libs/hashes.lua	Tue Jan 12 13:14:36 2016 +0000
@@ -1,3 +1,58 @@
-local sha1 = require "util.sha1";
+local have_luacrypto, crypto = pcall(require, "crypto");
+
+if have_luacrypto then
+	local hashes = {};
+
+	local digest = crypto.digest;
+	local function gethash(algo)
+		return function (string, hex)
+			return digest(algo, string, not hex);
+		end
+	end
+
+	local hmac = crypto.hmac.digest;
+	local function gethmac(algo)
+		return function (key, message, hex)
+			return hmac(algo, message, key, not hex);
+		end
+	end
+
+	local hash_algos = { "md5", "sha1", "sha256", "sha512" };
+
+	for _, hash_algo in ipairs(hash_algos) do
+		hashes[hash_algo] = gethash(hash_algo);
+		hashes["hmac_"..hash_algo] = gethmac(hash_algo);
+	end
 
-return { sha1 = sha1.sha1 };
+	return hashes;
+else
+	local sha1 = require"util.sha1".sha1;
+	local bxor = require"bit".bxor;
+
+	local s_rep = string.rep;
+	local s_char = string.char;
+	local s_byte = string.byte;
+	local t_concat = table.concat;
+
+	local function hmac_sha1(key, message, hexres)
+		if #key > 64 then
+			key = sha1(key);
+		elseif #key < 64 then
+			key = key .. s_rep("\0", 64 - #key);
+		end
+		local o_key_pad, i_key_pad = {}, {}
+		for i = 1, 64 do
+			local b = s_byte(key, i)
+			o_key_pad[i] = s_char(bxor(b, 0x5c));
+			i_key_pad[i] = s_char(bxor(b, 0x36));
+		end
+		o_key_pad = t_concat(o_key_pad);
+		i_key_pad = t_concat(i_key_pad);
+		return sha1(o_key_pad .. sha1(i_key_pad .. message), hexres);
+	end
+
+	return {
+		sha1 = sha1;
+		hmac_sha1 = hmac_sha1;
+	};
+end