md5

--[[
   *Apokalypsys, Dimus
   *http://minecrafting.ru/
   *http://minecrafting.ru/forum/viewtopic.php?f=32&t=5331
]]

local hex_char = "0123456789abcdef"

local function getHex(seed)
   local str = ""
   for i = 0, 3 do
      local ind1, ind2 = bit.band(bit.brshift(seed, i * 8 + 4), 15) + 1, bit.band(bit.brshift(seed, i * 8), 15) + 1
      str = str..
      hex_char:sub(ind1, ind1)..
      hex_char:sub(ind2, ind2)
   end
   return str
end

local function string_to_blks(str)
   local nblk = bit.brshift((str:len() + 8), 6) + 1
   local blks = {}
   local len = str:len()
   for i = 0, nblk * 16 - 1 do
      blks[i] = 0
   end
   for i = 0, str:len() - 1 do
      blks[bit.brshift(i, 2)] =
      bit.bor(
         blks[bit.brshift(i, 2)],
         bit.blshift(
            str:byte(i+1),
             (((i) % 4) * 8)
          )
      )
   end
      blks[bit.brshift(len, 2)] =
      bit.bor(
         blks[bit.brshift(len, 2)],
         bit.blshift(
            128,
            (((len) % 4) * 8)
         )
      )
      blks[nblk * 16 - 2] = len * 8
   return blks
end

local function add(x, y)
   return x + y > 4294967296 and x + y or x + y - 4294967296
end

local function rol(number, count)
   return bit.bor(bit.blshift(number, count), bit.blogic_rshift(number, (32 - count)))
end

local function X(a, b, c, x, s, t)
   return add(rol(add(add(b, a), add(x, t)), s), c)
end

local function F(a, b, c, d, x, s, t)
   return X(bit.bor(bit.band(b, c), bit.band(bit.bnot(b), d)), a, b, x, s, t)
end

local function G(a, b, c, d, x, s, t)
   return X(bit.bor(bit.band(b, d), bit.band(c, bit.bnot(d))), a, b, x, s, t)
end

local function H(a, b, c, d, x, s, t)
   return X(bit.bxor(bit.bxor(b, c), d), a, b, x, s, t)
end

local function I(a, b, c, d, x, s, t)
   return X(bit.bxor(c, bit.bor(b, bit.bnot(d))), a, b, x, s, t)
end

function md5(encoding_string)
   local blks = string_to_blks(encoding_string)

   local a = 1732584193
   local b = -271733879
   local c = -1732584194
   local d = 271733878

   for i = 0, #blks-1, 16 do
      local olda, oldb, oldc, oldd = a, b, c, d

      a = F(a, b, c, d, blks[i+ 0], 7, -680876936)
      d = F(d, a, b, c, blks[i+ 1], 12, -389564586)
      c = F(c, d, a, b, blks[i+ 2], 17, 606105819)
      b = F(b, c, d, a, blks[i+ 3], 22, -1044525330)
      a = F(a, b, c, d, blks[i+ 4], 7, -176418897)
      d = F(d, a, b, c, blks[i+ 5], 12, 1200080426)
      c = F(c, d, a, b, blks[i+ 6], 17, -1473231341)
      b = F(b, c, d, a, blks[i+ 7], 22, -45705983)
      a = F(a, b, c, d, blks[i+ 8], 7, 1770035416)
      d = F(d, a, b, c, blks[i+ 9], 12, -1958414417)
      c = F(c, d, a, b, blks[i+10], 17, -42063)
      b = F(b, c, d, a, blks[i+11], 22, -1990404162)
      a = F(a, b, c, d, blks[i+12], 7, 1804603682)
      d = F(d, a, b, c, blks[i+13], 12, -40341101)
      c = F(c, d, a, b, blks[i+14], 17, -1502002290)
      b = F(b, c, d, a, blks[i+15], 22, 1236535329)

      a = G(a, b, c, d, blks[i+ 1], 5, -165796510)
      d = G(d, a, b, c, blks[i+ 6], 9, -1069501632)
      c = G(c, d, a, b, blks[i+11], 14, 643717713)
      b = G(b, c, d, a, blks[i+ 0], 20, -373897302)
      a = G(a, b, c, d, blks[i+ 5], 5, -701558691)
      d = G(d, a, b, c, blks[i+10], 9, 38016083)
      c = G(c, d, a, b, blks[i+15], 14, -660478335)
      b = G(b, c, d, a, blks[i+ 4], 20, -405537848)
      a = G(a, b, c, d, blks[i+ 9], 5, 568446438)
      d = G(d, a, b, c, blks[i+14], 9, -1019803690)
      c = G(c, d, a, b, blks[i+ 3], 14, -187363961)
      b = G(b, c, d, a, blks[i+ 8], 20, 1163531501)
      a = G(a, b, c, d, blks[i+13], 5, -1444681467)
      d = G(d, a, b, c, blks[i+ 2], 9, -51403784)
      c = G(c, d, a, b, blks[i+ 7], 14, 1735328473)
      b = G(b, c, d, a, blks[i+12], 20, -1926607734)

      a = H(a, b, c, d, blks[i+ 5], 4, -378558)
      d = H(d, a, b, c, blks[i+ 8], 11, -2022574463)
      c = H(c, d, a, b, blks[i+11], 16, 1839030562)
      b = H(b, c, d, a, blks[i+14], 23, -35309556)
      a = H(a, b, c, d, blks[i+ 1], 4, -1530992060)
      d = H(d, a, b, c, blks[i+ 4], 11, 1272893353)
      c = H(c, d, a, b, blks[i+ 7], 16, -155497632)
      b = H(b, c, d, a, blks[i+10], 23, -1094730640)
      a = H(a, b, c, d, blks[i+13], 4, 681279174)
      d = H(d, a, b, c, blks[i+ 0], 11, -358537222)
      c = H(c, d, a, b, blks[i+ 3], 16, -722521979)
      b = H(b, c, d, a, blks[i+ 6], 23, 76029189)
      a = H(a, b, c, d, blks[i+ 9], 4, -640364487)
      d = H(d, a, b, c, blks[i+12], 11, -421815835)
      c = H(c, d, a, b, blks[i+15], 16, 530742520)
      b = H(b, c, d, a, blks[i+ 2], 23, -995338651)

      a = I(a, b, c, d, blks[i+ 0], 6, -198630844)
      d = I(d, a, b, c, blks[i+ 7], 10, 1126891415)
      c = I(c, d, a, b, blks[i+14], 15, -1416354905)
      b = I(b, c, d, a, blks[i+ 5], 21, -57434055)
      a = I(a, b, c, d, blks[i+12], 6, 1700485571)
      d = I(d, a, b, c, blks[i+ 3], 10, -1894986606)
      c = I(c, d, a, b, blks[i+10], 15, -1051523)
      b = I(b, c, d, a, blks[i+ 1], 21, -2054922799)
      a = I(a, b, c, d, blks[i+ 8], 6, 1873313359)
      d = I(d, a, b, c, blks[i+15], 10, -30611744)
      c = I(c, d, a, b, blks[i+ 6], 15, -1560198380)
      b = I(b, c, d, a, blks[i+13], 21, 1309151649)
      a = I(a, b, c, d, blks[i+ 4], 6, -145523070)
      d = I(d, a, b, c, blks[i+11], 10, -1120210379)
      c = I(c, d, a, b, blks[i+ 2], 15, 718787259)
      b = I(b, c, d, a, blks[i+ 9], 21, -343485551)

      a = add(a, olda)
      b = add(b, oldb)
      c = add(c, oldc)
      d = add(d, oldd)
   end
   return getHex(a)..getHex(b)..getHex(c)..getHex(d)
end