--- /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;