diff -r 000000000000 -r 598d09faf89c aeslua/util.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/aeslua/util.lua	Wed Feb 16 20:29:33 2011 +0000
@@ -0,0 +1,155 @@
+local bit = require("bit");
+
+local public = {};
+local private = {};
+
+local aeslua = require("aeslua");
+aeslua.util = public;
+
+--
+-- calculate the parity of one byte
+--
+function public.byteParity(byte)
+    byte = bit.bxor(byte, bit.rshift(byte, 4));
+    byte = bit.bxor(byte, bit.rshift(byte, 2));
+    byte = bit.bxor(byte, bit.rshift(byte, 1));
+    return bit.band(byte, 1);
+end
+
+-- 
+-- get byte at position index
+--
+function public.getByte(number, index)
+    if (index == 0) then
+        return bit.band(number,0xff);
+    else
+        return bit.band(bit.rshift(number, index*8),0xff);
+    end
+end
+
+
+--
+-- put number into int at position index
+--
+function public.putByte(number, index)
+    if (index == 0) then
+        return bit.band(number,0xff);
+    else
+        return bit.lshift(bit.band(number,0xff),index*8);
+    end
+end
+
+--
+-- convert byte array to int array
+--
+function public.bytesToInts(bytes, start, n)
+    local ints = {};
+    for i = 0, n - 1 do
+        ints[i] = public.putByte(bytes[start + (i*4)    ], 3)
+                + public.putByte(bytes[start + (i*4) + 1], 2) 
+                + public.putByte(bytes[start + (i*4) + 2], 1)    
+                + public.putByte(bytes[start + (i*4) + 3], 0);
+    end
+    return ints;
+end
+
+--
+-- convert int array to byte array
+--
+function public.intsToBytes(ints, output, outputOffset, n)
+    n = n or #ints;
+    for i = 0, n do
+        for j = 0,3 do
+            output[outputOffset + i*4 + (3 - j)] = public.getByte(ints[i], j);
+        end
+    end
+    return output;
+end
+
+--
+-- convert bytes to hexString
+--
+function private.bytesToHex(bytes)
+    local hexBytes = "";
+    
+    for i,byte in ipairs(bytes) do 
+        hexBytes = hexBytes .. string.format("%02x ", byte);
+    end
+
+    return hexBytes;
+end
+
+--
+-- convert data to hex string
+--
+function public.toHexString(data)
+    local type = type(data);
+    if (type == "number") then
+        return string.format("%08x",data);
+    elseif (type == "table") then
+        return private.bytesToHex(data);
+    elseif (type == "string") then
+        local bytes = {string.byte(data, 1, #data)}; 
+
+        return private.bytesToHex(bytes);
+    else
+        return data;
+    end
+end
+
+function public.padByteString(data)
+    local dataLength = #data;
+    
+    local random1 = math.random(0,255);
+    local random2 = math.random(0,255);
+
+    local prefix = string.char(random1,
+                               random2,
+                               random1,
+                               random2,
+                               public.getByte(dataLength, 3),
+                               public.getByte(dataLength, 2),
+                               public.getByte(dataLength, 1),
+                               public.getByte(dataLength, 0));
+
+    data = prefix .. data;
+
+    local paddingLength = math.ceil(#data/16)*16 - #data;
+    local padding = "";
+    for i=1,paddingLength do
+        padding = padding .. string.char(math.random(0,255));
+    end 
+
+    return data .. padding;
+end
+
+function private.properlyDecrypted(data)
+    local random = {string.byte(data,1,4)};
+
+    if (random[1] == random[3] and random[2] == random[4]) then
+        return true;
+    end
+    
+    return false;
+end
+
+function public.unpadByteString(data)
+    if (not private.properlyDecrypted(data)) then
+        return nil;
+    end
+
+    local dataLength = public.putByte(string.byte(data,5), 3)
+                     + public.putByte(string.byte(data,6), 2) 
+                     + public.putByte(string.byte(data,7), 1)    
+                     + public.putByte(string.byte(data,8), 0);
+    
+    return string.sub(data,9,8+dataLength);
+end
+
+function public.xorIV(data, iv)
+    for i = 1,16 do
+        data[i] = bit.bxor(data[i], iv[i]);
+    end 
+end
+
+return public;