From fc9269f362d2c19ff1e9f28205ab076b2175a5b2 Mon Sep 17 00:00:00 2001
From: Joakim Olsson <joakim@unbound.se>
Date: Fri, 2 Aug 2019 10:27:54 +0200
Subject: [PATCH] Change SHA-implementation and make sure signature is
 correctly generated

---
 .gitlab-ci.yml               |   2 +-
 Dockerfile                   |   4 +-
 deployment_files/deploy.yaml |   4 +
 hmac.lua                     | 133 +++++++
 nginx.conf                   |  34 +-
 sha2.lua                     | 242 ++++++++++++
 sha256.lua                   | 745 -----------------------------------
 sign.lua                     |  37 +-
 start.sh                     |   2 +
 test.lua                     |  40 +-
 10 files changed, 436 insertions(+), 807 deletions(-)
 create mode 100644 hmac.lua
 create mode 100644 sha2.lua
 delete mode 100644 sha256.lua

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4547a70..22c1ef7 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,7 +10,7 @@ image: registry.gitlab.com/sparetimecoders/build-tools:master
 build:
   stage: build
   services:
-    - docker:dind
+    - docker:18.06-dind
   script:
   - build
   - push
diff --git a/Dockerfile b/Dockerfile
index f526e45..946c16c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,7 +2,7 @@ FROM ubuntu
 
 # Install prerequisites for Nginx compile
 RUN apt-get update && \
-    apt-get install -y wget tar gcc libpcre3-dev zlib1g-dev make libssl-dev liblua5.1-0 libluajit-5.1-dev curl jq
+    apt-get install -y wget tar gcc libpcre3-dev zlib1g-dev make libssl-dev liblua5.1-0 lua-bit32 libluajit-5.1-dev curl jq
 
 # Download Nginx
 WORKDIR /tmp
@@ -56,7 +56,7 @@ RUN ln -sf /dev/stdout /var/log/nginx/access.log \
 
 # Apply Nginx config
 ADD nginx.conf /etc/nginx/nginx.conf
-ADD sign.lua sha256.lua /tmp/lua/
+ADD sign.lua hmac.lua sha2.lua /tmp/lua/
 ADD start.sh /start.sh
 
 # Set default command
diff --git a/deployment_files/deploy.yaml b/deployment_files/deploy.yaml
index 7c47b9b..e0d0137 100644
--- a/deployment_files/deploy.yaml
+++ b/deployment_files/deploy.yaml
@@ -52,6 +52,10 @@ spec:
         env:
           - name: S3_BUCKET_NAME
             value: upload.unbound.se
+          - name: AWS_REGION
+            value: eu-west-1
+          - name: RETURN_URL
+            value: uploads.unbound.se
         ports:
         - containerPort: 80
 
diff --git a/hmac.lua b/hmac.lua
new file mode 100644
index 0000000..77e1ece
--- /dev/null
+++ b/hmac.lua
@@ -0,0 +1,133 @@
+local _M = {}
+
+_M.to_bin = function (str)
+    local data = ''
+    str:lower():gsub('([a-z0-9])([a-z0-9])', function (d1, d2)
+        d1 = _M.hexdigit2int(d1)
+        d2 = _M.hexdigit2int(d2)
+        data = (data .. string.char(d1 * 16 + d2))
+    end)
+    return data
+end
+_M.to_hex = function (str)
+    local data = ''
+    for i=1,#str,1 do
+        data = (data .. ("%02x"):format(str:byte(i)))
+    end
+    return data
+end
+
+_M.hexdigit2int = function (ch)
+    local b = ch:byte()
+    if b >= ('a'):byte() then
+        return 10 + (b - ('a'):byte())
+    elseif b >= ('0'):byte() then
+        return b - ('0'):byte()
+    else
+        _M.assert(false)
+    end
+end
+
+_M.b64 = (function ()
+    -- character table string
+    local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
+    -- encoding
+    local function enc(data)
+        return ((data:gsub('.', function(x)
+            local r,b='',x:byte()
+            for i=8,1,-1 do r=r..(b%2^i-b%2^(i-1)>0 and '1' or '0') end
+            return r;
+        end)..'0000'):gsub('%d%d%d?%d?%d?%d?', function(x)
+            if (#x < 6) then return '' end
+            local c=0
+            for i=1,6 do c=c+(x:sub(i,i)=='1' and 2^(6-i) or 0) end
+            return b:sub(c+1,c+1)
+        end)..({ '', '==', '=' })[#data%3+1])
+    end
+
+    -- decoding
+    local function dec(data)
+        data = string.gsub(data, '[^'..b..'=]', '')
+        return (data:gsub('.', function(x)
+            if (x == '=') then return '' end
+            local r,f='',(b:find(x)-1)
+            for i=6,1,-1 do r=r..(f%2^i-f%2^(i-1)>0 and '1' or '0') end
+            return r;
+        end):gsub('%d%d%d?%d?%d?%d?%d?%d?', function(x)
+            if (#x ~= 8) then return '' end
+            local c=0
+            for i=1,8 do c=c+(x:sub(i,i)=='1' and 2^(8-i) or 0) end
+            return string.char(c)
+        end))
+    end
+    return {
+        encode = enc,
+        decode = dec,
+    }
+end)()
+
+_M.sha2 = require("sha2")
+
+_M.hmac = (function ()
+    --local hmac = require 'hmac'
+    local sha2 = _M.sha2
+
+    -- these hmac-ize routine is from https://github.com/bjc/prosody/blob/master/util/hmac.lua.
+    -- thanks!
+    local s_char = string.char;
+    local s_gsub = string.gsub;
+    local s_rep = string.rep;
+    local xor_map = {0;1;2;3;4;5;6;7;8;9;10;11;12;13;14;15;1;0;3;2;5;4;7;6;9;8;11;10;13;12;15;14;2;3;0;1;6;7;4;5;10;11;8;9;14;15;12;13;3;2;1;0;7;6;5;4;11;10;9;8;15;14;13;12;4;5;6;7;0;1;2;3;12;13;14;15;8;9;10;11;5;4;7;6;1;0;3;2;13;12;15;14;9;8;11;10;6;7;4;5;2;3;0;1;14;15;12;13;10;11;8;9;7;6;5;4;3;2;1;0;15;14;13;12;11;10;9;8;8;9;10;11;12;13;14;15;0;1;2;3;4;5;6;7;9;8;11;10;13;12;15;14;1;0;3;2;5;4;7;6;10;11;8;9;14;15;12;13;2;3;0;1;6;7;4;5;11;10;9;8;15;14;13;12;3;2;1;0;7;6;5;4;12;13;14;15;8;9;10;11;4;5;6;7;0;1;2;3;13;12;15;14;9;8;11;10;5;4;7;6;1;0;3;2;14;15;12;13;10;11;8;9;6;7;4;5;2;3;0;1;15;14;13;12;11;10;9;8;7;6;5;4;3;2;1;0;};
+    local function xor(x, y)
+        local lowx, lowy = x % 16, y % 16;
+        local hix, hiy = (x - lowx) / 16, (y - lowy) / 16;
+        local lowr, hir = xor_map[lowx * 16 + lowy + 1], xor_map[hix * 16 + hiy + 1];
+        local r = hir * 16 + lowr;
+        return r;
+    end
+    local opadc, ipadc = s_char(0x5c), s_char(0x36);
+    local ipad_map = {};
+    local opad_map = {};
+    for i=0,255 do
+        ipad_map[s_char(i)] = s_char(xor(0x36, i));
+        opad_map[s_char(i)] = s_char(xor(0x5c, i));
+    end
+    local function hmac(key, message, hash, blocksize)
+        if #key > blocksize then
+            key = hash(key)
+        end
+
+        local padding = blocksize - #key;
+        local ipad = s_gsub(key, ".", ipad_map)..s_rep(ipadc, padding);
+        local opad = s_gsub(key, ".", opad_map)..s_rep(opadc, padding);
+
+        return hash(opad..hash(ipad..message))
+    end
+    local sha256 = function (data)
+        local text = sha2.hash256(data)
+        return _M.to_bin(text)
+    end
+    local digest_routines = {
+        hex = _M.to_hex,
+        base64 = _M.b64.encode
+    }
+    local hmac_sha256 = function (key, data, digest)
+        local bin = hmac(key, data, sha256, 64)
+        --	print(_M.to_hex(bin))
+        --local bin = _M.to_bin("8BDD6729CE0F580B7424921D5F0CFD1F1642243762CBA71FFCC8FABCFC72608B")
+        return digest_routines[digest] and digest_routines[digest](bin) or bin
+    end
+
+    local hmac_sha1 = function (key, data, digest)
+        local bin = sha1.sha1_bin(key, data)
+        return digest_routines[digest] and digest_routines[digest](bin) or bin
+    end
+
+    _M.hmac_by = {
+        sha256 = hmac_sha256,
+        sha1 = hmac_sha1,
+    }
+    return hmac_sha256
+end)()
+
+return _M
diff --git a/nginx.conf b/nginx.conf
index 04fe458..0dd731a 100644
--- a/nginx.conf
+++ b/nginx.conf
@@ -1,6 +1,8 @@
 env AWS_ACCESS_KEY_ID;
 env AWS_SECRET_ACCESS_KEY;
 env S3_BUCKET_NAME;
+env AWS_REGION;
+env RETURN_URL;
 
 worker_processes 1;
 
@@ -11,10 +13,15 @@ events {
 http {
   lua_load_resty_core off;
   lua_package_path "/tmp/lua-resty-core/lib/?.lua;/tmp/lua/?.lua;;";
-  client_max_body_size 100m;
+  lua_package_cpath '/usr/lib/x86_64-linux-gnu/lua/5.1/?.so;;';
+
+  proxy_max_temp_file_size 0;
+  proxy_buffering off;
+  server_names_hash_bucket_size 256;
   client_body_buffer_size 128k;
   proxy_buffer_size 32k;
   proxy_buffers 4 32k;
+
   lua_need_request_body on;
   lua_socket_buffer_size 128k;
 
@@ -47,34 +54,37 @@ http {
       set_secure_random_alphanum $prefix 64;
       set_sha1 $prefixsha $prefix;
       set_by_lua $time "os.time()";
+      set_by_lua $timestamp "return os.date('%Y%m%dT%H%M%SZ', tonumber(ngx.var.time))";
       set_by_lua $date "return os.date('%a, %d %b %Y %H:%M:%S GMT', tonumber(ngx.var.time))";
       set_by_lua $day "return os.date('%Y%m%d', tonumber(ngx.var.time))";
       set_sha1 $datesha $date;
       set $key $prefixsha$datesha;
       set_by_lua $bucket "return os.getenv('S3_BUCKET_NAME')";
-      set $url https://$bucket.s3-eu-west-1.amazonaws.com/$day/$key;
-      set $returnurl https://uploads.paidit.se/$day/$key;
+      set_by_lua $baseurl "return os.getenv('RETURN_URL')";
+      set_by_lua $region "return os.getenv('AWS_REGION')";
+      set $phost $bucket.s3-$region.amazonaws.com;
+      set $ppath /$day/$key;
+      set $url https://$phost$ppath;
+      set $returnurl https://$baseurl$ppath;
       set $acl public-read;
       set $contentSha256 "";
+      set $authorization "";
 
       access_by_lua_block {
-        local sha256 = require("sha256")
+        local sha2 = require("sha2")
         ngx.req.read_body()
         local body = ngx.req.get_body_data()
-        local contentSha256 = sha256.sha256(body)
+        local contentSha256 = sha2.hash256(body)
         ngx.var.contentSha256 = contentSha256
-      }
-
-      set_by_lua_block $authorization {
         local sign = require("sign")
-        local headers = {["x-amz-acl"] = ngx.var.acl, ["x-amz-date"] = ngx.var.date, ["host"] = "upload.unbound.se.s3-eu-west-1.amazonaws.com"}
-        local region = "eu-west-1"
-        return sign.sign(os.getenv("AWS_ACCESS_KEY_ID"), os.getenv("AWS_SECRET_ACCESS_KEY"), os.time(), "upload.unbound.se", ngx.var.request_uri, headers, ngx.var.contentSha256, region)
+        local headers = {["x-amz-acl"] = ngx.var.acl, ["x-amz-date"] = ngx.var.timestamp, ["x-amz-content-sha256"] = ngx.var.contentSha256, ["date"] = ngx.var.date, ["host"] = ngx.var.phost }
+        ngx.var.authorization = sign.sign(os.getenv("AWS_ACCESS_KEY_ID"), os.getenv("AWS_SECRET_ACCESS_KEY"), os.time(), ngx.var.ppath, headers, ngx.var.region)
       }
 
       proxy_set_header date $date;
+      proxy_set_header host $phost;
       proxy_set_header x-amz-acl $acl;
-      proxy_set_header x-amz-date $date;
+      proxy_set_header x-amz-date $timestamp;
       proxy_set_header x-amz-content-sha256 $contentSha256;
       proxy_set_header Authorization $authorization;
       proxy_hide_header x-amz-id-2;
diff --git a/sha2.lua b/sha2.lua
new file mode 100644
index 0000000..1c374c9
--- /dev/null
+++ b/sha2.lua
@@ -0,0 +1,242 @@
+-- SHA-256 code in Lua 5.2; based on the pseudo-code from
+-- Wikipedia (http://en.wikipedia.org/wiki/SHA-2)
+
+local bit32 = require("bit32")
+
+local band, rrotate, bxor, rshift, bnot =
+bit32.band, bit32.rrotate, bit32.bxor, bit32.rshift, bit32.bnot
+
+local string, setmetatable, assert = string, setmetatable, assert
+
+_ENV = nil
+
+-- Initialize table of round constants
+-- (first 32 bits of the fractional parts of the cube roots of the first
+-- 64 primes 2..311):
+local k = {
+    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
+    0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
+    0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
+    0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
+    0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
+    0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
+}
+
+
+-- transform a string of bytes in a string of hexadecimal digits
+local function str2hexa (s)
+    local h = string.gsub(s, ".", function(c)
+        return string.format("%02x", string.byte(c))
+    end)
+    return h
+end
+
+
+-- transform number 'l' in a big-endian sequence of 'n' bytes
+-- (coded as a string)
+local function num2s (l, n)
+    local s = ""
+    for i = 1, n do
+        local rem = l % 256
+        s = string.char(rem) .. s
+        l = (l - rem) / 256
+    end
+    return s
+end
+
+-- transform the big-endian sequence of four bytes starting at
+-- index 'i' in 's' into a number
+local function s232num (s, i)
+    local n = 0
+    for i = i, i + 3 do
+        n = n*256 + string.byte(s, i)
+    end
+    return n
+end
+
+
+-- append the bit '1' to the message
+-- append k bits '0', where k is the minimum number >= 0 such that the
+-- resulting message length (in bits) is congruent to 448 (mod 512)
+-- append length of message (before pre-processing), in bits, as 64-bit
+-- big-endian integer
+local function preproc (msg, len)
+    local extra = -(len + 1 + 8) % 64
+    len = num2s(8 * len, 8)    -- original len in bits, coded
+    msg = msg .. "\128" .. string.rep("\0", extra) .. len
+    assert(#msg % 64 == 0)
+    return msg
+end
+
+
+local function initH224 (H)
+    -- (second 32 bits of the fractional parts of the square roots of the
+    -- 9th through 16th primes 23..53)
+    H[1] = 0xc1059ed8
+    H[2] = 0x367cd507
+    H[3] = 0x3070dd17
+    H[4] = 0xf70e5939
+    H[5] = 0xffc00b31
+    H[6] = 0x68581511
+    H[7] = 0x64f98fa7
+    H[8] = 0xbefa4fa4
+    return H
+end
+
+
+local function initH256 (H)
+    -- (first 32 bits of the fractional parts of the square roots of the
+    -- first 8 primes 2..19):
+    H[1] = 0x6a09e667
+    H[2] = 0xbb67ae85
+    H[3] = 0x3c6ef372
+    H[4] = 0xa54ff53a
+    H[5] = 0x510e527f
+    H[6] = 0x9b05688c
+    H[7] = 0x1f83d9ab
+    H[8] = 0x5be0cd19
+    return H
+end
+
+
+local function digestblock (msg, i, H)
+
+    -- break chunk into sixteen 32-bit big-endian words w[1..16]
+    local w = {}
+    for j = 1, 16 do
+        w[j] = s232num(msg, i + (j - 1)*4)
+    end
+
+    -- Extend the sixteen 32-bit words into sixty-four 32-bit words:
+    for j = 17, 64 do
+        local v = w[j - 15]
+        local s0 = bxor(rrotate(v, 7), rrotate(v, 18), rshift(v, 3))
+        v = w[j - 2]
+        local s1 = bxor(rrotate(v, 17), rrotate(v, 19), rshift(v, 10))
+        w[j] = w[j - 16] + s0 + w[j - 7] + s1
+    end
+
+    -- Initialize hash value for this chunk:
+    local a, b, c, d, e, f, g, h =
+    H[1], H[2], H[3], H[4], H[5], H[6], H[7], H[8]
+
+    -- Main loop:
+    for i = 1, 64 do
+        local s0 = bxor(rrotate(a, 2), rrotate(a, 13), rrotate(a, 22))
+        local maj = bxor(band(a, b), band(a, c), band(b, c))
+        local t2 = s0 + maj
+        local s1 = bxor(rrotate(e, 6), rrotate(e, 11), rrotate(e, 25))
+        local ch = bxor (band(e, f), band(bnot(e), g))
+        local t1 = h + s1 + ch + k[i] + w[i]
+
+        h = g
+        g = f
+        f = e
+        e = d + t1
+        d = c
+        c = b
+        b = a
+        a = t1 + t2
+    end
+
+    -- Add (mod 2^32) this chunk's hash to result so far:
+    H[1] = band(H[1] + a)
+    H[2] = band(H[2] + b)
+    H[3] = band(H[3] + c)
+    H[4] = band(H[4] + d)
+    H[5] = band(H[5] + e)
+    H[6] = band(H[6] + f)
+    H[7] = band(H[7] + g)
+    H[8] = band(H[8] + h)
+
+end
+
+
+local function finalresult224 (H)
+    -- Produce the final hash value (big-endian):
+    return
+    str2hexa(num2s(H[1], 4)..num2s(H[2], 4)..num2s(H[3], 4)..num2s(H[4], 4)..
+            num2s(H[5], 4)..num2s(H[6], 4)..num2s(H[7], 4))
+end
+
+
+local function finalresult256 (H)
+    -- Produce the final hash value (big-endian):
+    return
+    str2hexa(num2s(H[1], 4)..num2s(H[2], 4)..num2s(H[3], 4)..num2s(H[4], 4)..
+            num2s(H[5], 4)..num2s(H[6], 4)..num2s(H[7], 4)..num2s(H[8], 4))
+end
+
+
+----------------------------------------------------------------------
+local HH = {}    -- to reuse
+
+local function hash224 (msg)
+    msg = preproc(msg, #msg)
+    local H = initH224(HH)
+
+    -- Process the message in successive 512-bit (64 bytes) chunks:
+    for i = 1, #msg, 64 do
+        digestblock(msg, i, H)
+    end
+
+    return finalresult224(H)
+end
+
+
+local function hash256 (msg)
+    msg = preproc(msg, #msg)
+    local H = initH256(HH)
+
+    -- Process the message in successive 512-bit (64 bytes) chunks:
+    for i = 1, #msg, 64 do
+        digestblock(msg, i, H)
+    end
+
+    return finalresult256(H)
+end
+----------------------------------------------------------------------
+local mt = {}
+
+local function new256 ()
+    local o = {H = initH256({}), msg = "", len = 0}
+    setmetatable(o, mt)
+    return o
+end
+
+mt.__index = mt
+
+function mt:add (m)
+    self.msg = self.msg .. m
+    self.len = self.len + #m
+    local t = 0
+    while #self.msg - t >= 64 do
+        digestblock(self.msg, t + 1, self.H)
+        t = t + 64
+    end
+    self.msg = self.msg:sub(t + 1, -1)
+end
+
+
+function mt:close ()
+    self.msg = preproc(self.msg, self.len)
+    self:add("")
+    return finalresult256(self.H)
+end
+----------------------------------------------------------------------
+
+return {
+    hash224 = hash224,
+    hash256 = hash256,
+    new256 = new256,
+}
diff --git a/sha256.lua b/sha256.lua
deleted file mode 100644
index 50fbc3a..0000000
--- a/sha256.lua
+++ /dev/null
@@ -1,745 +0,0 @@
---
--- SHA-256 secure hash computation, and HMAC-SHA256 signature computation
---
--- Copyright 2017 Jqqqi
---
-local sha256 = { }
-
-local MOD = 2 ^ 32
-local MODM = MOD - 1
- 
-local function memoize(f)
-	local mt = { }
-	local t = setmetatable( { }, mt)
-	function mt:__index(k)
-		local v = f(k)
-		t[k] = v
-		return v
-	end
-	return t
-end
- 
-local function make_bitop_uncached(t, m)
-	local function bitop(a, b)
-		local res, p = 0, 1
-		while a ~= 0 and b ~= 0 do
-			local am, bm = a % m, b % m
-			res = res + t[am][bm] * p
-			a =(a - am) / m
-			b =(b - bm) / m
-			p = p * m
-		end
-		res = res +(a + b) * p
-		return res
-	end
-	return bitop
-end
- 
-local function make_bitop(t)
-	local op1 = make_bitop_uncached(t, 2 ^ 1)
-	local op2 = memoize( function(a) return memoize( function(b) return op1(a, b) end) end)
-	return make_bitop_uncached(op2, 2 ^(t.n or 1))
-end
- 
-local bxor1 = make_bitop( { [0] = { [0] = 0, [1] = 1 }, [1] = { [0] = 1, [1] = 0 }, n = 4 })
- 
-local function bxor(a, b, c, ...)
-	local z = nil
-	if b then
-		a = a % MOD
-		b = b % MOD
-		z = bxor1(a, b)
-		if c then z = bxor(z, c, ...) end
-		return z
-	elseif a then
-		return a % MOD
-	else
-		return 0
-	end
-end
- 
-local function band(a, b, c, ...)
-	local z
-	if b then
-		a = a % MOD
-		b = b % MOD
-		z =((a + b) - bxor1(a, b)) / 2
-		if c then z = bit32_band(z, c, ...) end
-		return z
-	elseif a then
-		return a % MOD
-	else
-		return MODM
-	end
-end
- 
-local function bnot(x) return(-1 - x) % MOD end
- 
-local function rshift1(a, disp)
-	if disp < 0 then return lshift(a, - disp) end
-	return math.floor(a % 2 ^ 32 / 2 ^ disp)
-end
- 
-local function rshift(x, disp)
-	if disp > 31 or disp < -31 then return 0 end
-	return rshift1(x % MOD, disp)
-end
- 
-local function lshift(a, disp)
-	if disp < 0 then return rshift(a, - disp) end
-	return(a * 2 ^ disp) % 2 ^ 32
-end
- 
-local function rrotate(x, disp)
-	x = x % MOD
-	disp = disp % 32
-	local low = band(x, 2 ^ disp - 1)
-	return rshift(x, disp) + lshift(low, 32 - disp)
-end
- 
-local k = {
-	0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,
-	0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,
-	0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,
-	0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,
-	0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,
-	0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,
-	0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,
-	0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,
-	0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,
-	0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,
-	0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,
-	0xd192e819,0xd6990624,0xf40e3585,0x106aa070,
-	0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,
-	0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,
-	0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,
-	0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2,
-}
- 
-local function str2hexa(s)
-	return(string.gsub(s, ".", function(c) return string.format("%02x", string.byte(c)) end))
-end
- 
-local function num2s(l, n)
-	local s = ""
-	for i = 1, n do
-		local rem = l % 256
-		s = string.char(rem) .. s
-		l =(l - rem) / 256
-	end
-	return s
-end
- 
-local function s232num(s, i)
-	local n = 0
-	for i = i, i + 3 do n = n * 256 + string.byte(s, i) end
-	return n
-end
- 
-local function preproc(msg, len)
-	local extra = 64 -((len + 9) % 64)
-	len = num2s(8 * len, 8)
-	msg = msg .. "\128" .. string.rep("\0", extra) .. len
-	assert(#msg % 64 == 0)
-	return msg
-end
- 
-local function initH256(H)
-	H[1] = 0x6a09e667
-	H[2] = 0xbb67ae85
-	H[3] = 0x3c6ef372
-	H[4] = 0xa54ff53a
-	H[5] = 0x510e527f
-	H[6] = 0x9b05688c
-	H[7] = 0x1f83d9ab
-	H[8] = 0x5be0cd19
-	return H
-end
- 
-local function digestblock(msg, i, H)
-	local w = { }
-	for j = 1, 16 do w[j] = s232num(msg, i +(j - 1) * 4) end
-	for j = 17, 64 do
-		local v = w[j - 15]
-		local s0 = bxor(rrotate(v, 7), rrotate(v, 18), rshift(v, 3))
-		v = w[j - 2]
-		w[j] = w[j - 16] + s0 + w[j - 7] + bxor(rrotate(v, 17), rrotate(v, 19), rshift(v, 10))
-	end
-
-	local a, b, c, d, e, f, g, h = H[1], H[2], H[3], H[4], H[5], H[6], H[7], H[8]
-	for i = 1, 64 do
-		local s0 = bxor(rrotate(a, 2), rrotate(a, 13), rrotate(a, 22))
-		local maj = bxor(band(a, b), band(a, c), band(b, c))
-		local t2 = s0 + maj
-		local s1 = bxor(rrotate(e, 6), rrotate(e, 11), rrotate(e, 25))
-		local ch = bxor(band(e, f), band(bnot(e), g))
-		local t1 = h + s1 + ch + k[i] + w[i]
-		h, g, f, e, d, c, b, a = g, f, e, d + t1, c, b, a, t1 + t2
-	end
-
-	H[1] = band(H[1] + a)
-	H[2] = band(H[2] + b)
-	H[3] = band(H[3] + c)
-	H[4] = band(H[4] + d)
-	H[5] = band(H[5] + e)
-	H[6] = band(H[6] + f)
-	H[7] = band(H[7] + g)
-	H[8] = band(H[8] + h)
-end
-
-local function hex_to_binary(hex)
-	return hex:gsub('..', function(hexval)
-		return string.char(tonumber(hexval, 16))
-	end )
-end
-
-local blocksize = 64 -- 512 bits
-
-local xor_with_0x5c = {
-	[string.char(0)] = string.char(92),
-	[string.char(1)] = string.char(93),
-	[string.char(2)] = string.char(94),
-	[string.char(3)] = string.char(95),
-	[string.char(4)] = string.char(88),
-	[string.char(5)] = string.char(89),
-	[string.char(6)] = string.char(90),
-	[string.char(7)] = string.char(91),
-	[string.char(8)] = string.char(84),
-	[string.char(9)] = string.char(85),
-	[string.char(10)] = string.char(86),
-	[string.char(11)] = string.char(87),
-	[string.char(12)] = string.char(80),
-	[string.char(13)] = string.char(81),
-	[string.char(14)] = string.char(82),
-	[string.char(15)] = string.char(83),
-	[string.char(16)] = string.char(76),
-	[string.char(17)] = string.char(77),
-	[string.char(18)] = string.char(78),
-	[string.char(19)] = string.char(79),
-	[string.char(20)] = string.char(72),
-	[string.char(21)] = string.char(73),
-	[string.char(22)] = string.char(74),
-	[string.char(23)] = string.char(75),
-	[string.char(24)] = string.char(68),
-	[string.char(25)] = string.char(69),
-	[string.char(26)] = string.char(70),
-	[string.char(27)] = string.char(71),
-	[string.char(28)] = string.char(64),
-	[string.char(29)] = string.char(65),
-	[string.char(30)] = string.char(66),
-	[string.char(31)] = string.char(67),
-	[string.char(32)] = string.char(124),
-	[string.char(33)] = string.char(125),
-	[string.char(34)] = string.char(126),
-	[string.char(35)] = string.char(127),
-	[string.char(36)] = string.char(120),
-	[string.char(37)] = string.char(121),
-	[string.char(38)] = string.char(122),
-	[string.char(39)] = string.char(123),
-	[string.char(40)] = string.char(116),
-	[string.char(41)] = string.char(117),
-	[string.char(42)] = string.char(118),
-	[string.char(43)] = string.char(119),
-	[string.char(44)] = string.char(112),
-	[string.char(45)] = string.char(113),
-	[string.char(46)] = string.char(114),
-	[string.char(47)] = string.char(115),
-	[string.char(48)] = string.char(108),
-	[string.char(49)] = string.char(109),
-	[string.char(50)] = string.char(110),
-	[string.char(51)] = string.char(111),
-	[string.char(52)] = string.char(104),
-	[string.char(53)] = string.char(105),
-	[string.char(54)] = string.char(106),
-	[string.char(55)] = string.char(107),
-	[string.char(56)] = string.char(100),
-	[string.char(57)] = string.char(101),
-	[string.char(58)] = string.char(102),
-	[string.char(59)] = string.char(103),
-	[string.char(60)] = string.char(96),
-	[string.char(61)] = string.char(97),
-	[string.char(62)] = string.char(98),
-	[string.char(63)] = string.char(99),
-	[string.char(64)] = string.char(28),
-	[string.char(65)] = string.char(29),
-	[string.char(66)] = string.char(30),
-	[string.char(67)] = string.char(31),
-	[string.char(68)] = string.char(24),
-	[string.char(69)] = string.char(25),
-	[string.char(70)] = string.char(26),
-	[string.char(71)] = string.char(27),
-	[string.char(72)] = string.char(20),
-	[string.char(73)] = string.char(21),
-	[string.char(74)] = string.char(22),
-	[string.char(75)] = string.char(23),
-	[string.char(76)] = string.char(16),
-	[string.char(77)] = string.char(17),
-	[string.char(78)] = string.char(18),
-	[string.char(79)] = string.char(19),
-	[string.char(80)] = string.char(12),
-	[string.char(81)] = string.char(13),
-	[string.char(82)] = string.char(14),
-	[string.char(83)] = string.char(15),
-	[string.char(84)] = string.char(8),
-	[string.char(85)] = string.char(9),
-	[string.char(86)] = string.char(10),
-	[string.char(87)] = string.char(11),
-	[string.char(88)] = string.char(4),
-	[string.char(89)] = string.char(5),
-	[string.char(90)] = string.char(6),
-	[string.char(91)] = string.char(7),
-	[string.char(92)] = string.char(0),
-	[string.char(93)] = string.char(1),
-	[string.char(94)] = string.char(2),
-	[string.char(95)] = string.char(3),
-	[string.char(96)] = string.char(60),
-	[string.char(97)] = string.char(61),
-	[string.char(98)] = string.char(62),
-	[string.char(99)] = string.char(63),
-	[string.char(100)] = string.char(56),
-	[string.char(101)] = string.char(57),
-	[string.char(102)] = string.char(58),
-	[string.char(103)] = string.char(59),
-	[string.char(104)] = string.char(52),
-	[string.char(105)] = string.char(53),
-	[string.char(106)] = string.char(54),
-	[string.char(107)] = string.char(55),
-	[string.char(108)] = string.char(48),
-	[string.char(109)] = string.char(49),
-	[string.char(110)] = string.char(50),
-	[string.char(111)] = string.char(51),
-	[string.char(112)] = string.char(44),
-	[string.char(113)] = string.char(45),
-	[string.char(114)] = string.char(46),
-	[string.char(115)] = string.char(47),
-	[string.char(116)] = string.char(40),
-	[string.char(117)] = string.char(41),
-	[string.char(118)] = string.char(42),
-	[string.char(119)] = string.char(43),
-	[string.char(120)] = string.char(36),
-	[string.char(121)] = string.char(37),
-	[string.char(122)] = string.char(38),
-	[string.char(123)] = string.char(39),
-	[string.char(124)] = string.char(32),
-	[string.char(125)] = string.char(33),
-	[string.char(126)] = string.char(34),
-	[string.char(127)] = string.char(35),
-	[string.char(128)] = string.char(220),
-	[string.char(129)] = string.char(221),
-	[string.char(130)] = string.char(222),
-	[string.char(131)] = string.char(223),
-	[string.char(132)] = string.char(216),
-	[string.char(133)] = string.char(217),
-	[string.char(134)] = string.char(218),
-	[string.char(135)] = string.char(219),
-	[string.char(136)] = string.char(212),
-	[string.char(137)] = string.char(213),
-	[string.char(138)] = string.char(214),
-	[string.char(139)] = string.char(215),
-	[string.char(140)] = string.char(208),
-	[string.char(141)] = string.char(209),
-	[string.char(142)] = string.char(210),
-	[string.char(143)] = string.char(211),
-	[string.char(144)] = string.char(204),
-	[string.char(145)] = string.char(205),
-	[string.char(146)] = string.char(206),
-	[string.char(147)] = string.char(207),
-	[string.char(148)] = string.char(200),
-	[string.char(149)] = string.char(201),
-	[string.char(150)] = string.char(202),
-	[string.char(151)] = string.char(203),
-	[string.char(152)] = string.char(196),
-	[string.char(153)] = string.char(197),
-	[string.char(154)] = string.char(198),
-	[string.char(155)] = string.char(199),
-	[string.char(156)] = string.char(192),
-	[string.char(157)] = string.char(193),
-	[string.char(158)] = string.char(194),
-	[string.char(159)] = string.char(195),
-	[string.char(160)] = string.char(252),
-	[string.char(161)] = string.char(253),
-	[string.char(162)] = string.char(254),
-	[string.char(163)] = string.char(255),
-	[string.char(164)] = string.char(248),
-	[string.char(165)] = string.char(249),
-	[string.char(166)] = string.char(250),
-	[string.char(167)] = string.char(251),
-	[string.char(168)] = string.char(244),
-	[string.char(169)] = string.char(245),
-	[string.char(170)] = string.char(246),
-	[string.char(171)] = string.char(247),
-	[string.char(172)] = string.char(240),
-	[string.char(173)] = string.char(241),
-	[string.char(174)] = string.char(242),
-	[string.char(175)] = string.char(243),
-	[string.char(176)] = string.char(236),
-	[string.char(177)] = string.char(237),
-	[string.char(178)] = string.char(238),
-	[string.char(179)] = string.char(239),
-	[string.char(180)] = string.char(232),
-	[string.char(181)] = string.char(233),
-	[string.char(182)] = string.char(234),
-	[string.char(183)] = string.char(235),
-	[string.char(184)] = string.char(228),
-	[string.char(185)] = string.char(229),
-	[string.char(186)] = string.char(230),
-	[string.char(187)] = string.char(231),
-	[string.char(188)] = string.char(224),
-	[string.char(189)] = string.char(225),
-	[string.char(190)] = string.char(226),
-	[string.char(191)] = string.char(227),
-	[string.char(192)] = string.char(156),
-	[string.char(193)] = string.char(157),
-	[string.char(194)] = string.char(158),
-	[string.char(195)] = string.char(159),
-	[string.char(196)] = string.char(152),
-	[string.char(197)] = string.char(153),
-	[string.char(198)] = string.char(154),
-	[string.char(199)] = string.char(155),
-	[string.char(200)] = string.char(148),
-	[string.char(201)] = string.char(149),
-	[string.char(202)] = string.char(150),
-	[string.char(203)] = string.char(151),
-	[string.char(204)] = string.char(144),
-	[string.char(205)] = string.char(145),
-	[string.char(206)] = string.char(146),
-	[string.char(207)] = string.char(147),
-	[string.char(208)] = string.char(140),
-	[string.char(209)] = string.char(141),
-	[string.char(210)] = string.char(142),
-	[string.char(211)] = string.char(143),
-	[string.char(212)] = string.char(136),
-	[string.char(213)] = string.char(137),
-	[string.char(214)] = string.char(138),
-	[string.char(215)] = string.char(139),
-	[string.char(216)] = string.char(132),
-	[string.char(217)] = string.char(133),
-	[string.char(218)] = string.char(134),
-	[string.char(219)] = string.char(135),
-	[string.char(220)] = string.char(128),
-	[string.char(221)] = string.char(129),
-	[string.char(222)] = string.char(130),
-	[string.char(223)] = string.char(131),
-	[string.char(224)] = string.char(188),
-	[string.char(225)] = string.char(189),
-	[string.char(226)] = string.char(190),
-	[string.char(227)] = string.char(191),
-	[string.char(228)] = string.char(184),
-	[string.char(229)] = string.char(185),
-	[string.char(230)] = string.char(186),
-	[string.char(231)] = string.char(187),
-	[string.char(232)] = string.char(180),
-	[string.char(233)] = string.char(181),
-	[string.char(234)] = string.char(182),
-	[string.char(235)] = string.char(183),
-	[string.char(236)] = string.char(176),
-	[string.char(237)] = string.char(177),
-	[string.char(238)] = string.char(178),
-	[string.char(239)] = string.char(179),
-	[string.char(240)] = string.char(172),
-	[string.char(241)] = string.char(173),
-	[string.char(242)] = string.char(174),
-	[string.char(243)] = string.char(175),
-	[string.char(244)] = string.char(168),
-	[string.char(245)] = string.char(169),
-	[string.char(246)] = string.char(170),
-	[string.char(247)] = string.char(171),
-	[string.char(248)] = string.char(164),
-	[string.char(249)] = string.char(165),
-	[string.char(250)] = string.char(166),
-	[string.char(251)] = string.char(167),
-	[string.char(252)] = string.char(160),
-	[string.char(253)] = string.char(161),
-	[string.char(254)] = string.char(162),
-	[string.char(255)] = string.char(163),
-}
-
-local xor_with_0x36 = {
-	[string.char(0)] = string.char(54),
-	[string.char(1)] = string.char(55),
-	[string.char(2)] = string.char(52),
-	[string.char(3)] = string.char(53),
-	[string.char(4)] = string.char(50),
-	[string.char(5)] = string.char(51),
-	[string.char(6)] = string.char(48),
-	[string.char(7)] = string.char(49),
-	[string.char(8)] = string.char(62),
-	[string.char(9)] = string.char(63),
-	[string.char(10)] = string.char(60),
-	[string.char(11)] = string.char(61),
-	[string.char(12)] = string.char(58),
-	[string.char(13)] = string.char(59),
-	[string.char(14)] = string.char(56),
-	[string.char(15)] = string.char(57),
-	[string.char(16)] = string.char(38),
-	[string.char(17)] = string.char(39),
-	[string.char(18)] = string.char(36),
-	[string.char(19)] = string.char(37),
-	[string.char(20)] = string.char(34),
-	[string.char(21)] = string.char(35),
-	[string.char(22)] = string.char(32),
-	[string.char(23)] = string.char(33),
-	[string.char(24)] = string.char(46),
-	[string.char(25)] = string.char(47),
-	[string.char(26)] = string.char(44),
-	[string.char(27)] = string.char(45),
-	[string.char(28)] = string.char(42),
-	[string.char(29)] = string.char(43),
-	[string.char(30)] = string.char(40),
-	[string.char(31)] = string.char(41),
-	[string.char(32)] = string.char(22),
-	[string.char(33)] = string.char(23),
-	[string.char(34)] = string.char(20),
-	[string.char(35)] = string.char(21),
-	[string.char(36)] = string.char(18),
-	[string.char(37)] = string.char(19),
-	[string.char(38)] = string.char(16),
-	[string.char(39)] = string.char(17),
-	[string.char(40)] = string.char(30),
-	[string.char(41)] = string.char(31),
-	[string.char(42)] = string.char(28),
-	[string.char(43)] = string.char(29),
-	[string.char(44)] = string.char(26),
-	[string.char(45)] = string.char(27),
-	[string.char(46)] = string.char(24),
-	[string.char(47)] = string.char(25),
-	[string.char(48)] = string.char(6),
-	[string.char(49)] = string.char(7),
-	[string.char(50)] = string.char(4),
-	[string.char(51)] = string.char(5),
-	[string.char(52)] = string.char(2),
-	[string.char(53)] = string.char(3),
-	[string.char(54)] = string.char(0),
-	[string.char(55)] = string.char(1),
-	[string.char(56)] = string.char(14),
-	[string.char(57)] = string.char(15),
-	[string.char(58)] = string.char(12),
-	[string.char(59)] = string.char(13),
-	[string.char(60)] = string.char(10),
-	[string.char(61)] = string.char(11),
-	[string.char(62)] = string.char(8),
-	[string.char(63)] = string.char(9),
-	[string.char(64)] = string.char(118),
-	[string.char(65)] = string.char(119),
-	[string.char(66)] = string.char(116),
-	[string.char(67)] = string.char(117),
-	[string.char(68)] = string.char(114),
-	[string.char(69)] = string.char(115),
-	[string.char(70)] = string.char(112),
-	[string.char(71)] = string.char(113),
-	[string.char(72)] = string.char(126),
-	[string.char(73)] = string.char(127),
-	[string.char(74)] = string.char(124),
-	[string.char(75)] = string.char(125),
-	[string.char(76)] = string.char(122),
-	[string.char(77)] = string.char(123),
-	[string.char(78)] = string.char(120),
-	[string.char(79)] = string.char(121),
-	[string.char(80)] = string.char(102),
-	[string.char(81)] = string.char(103),
-	[string.char(82)] = string.char(100),
-	[string.char(83)] = string.char(101),
-	[string.char(84)] = string.char(98),
-	[string.char(85)] = string.char(99),
-	[string.char(86)] = string.char(96),
-	[string.char(87)] = string.char(97),
-	[string.char(88)] = string.char(110),
-	[string.char(89)] = string.char(111),
-	[string.char(90)] = string.char(108),
-	[string.char(91)] = string.char(109),
-	[string.char(92)] = string.char(106),
-	[string.char(93)] = string.char(107),
-	[string.char(94)] = string.char(104),
-	[string.char(95)] = string.char(105),
-	[string.char(96)] = string.char(86),
-	[string.char(97)] = string.char(87),
-	[string.char(98)] = string.char(84),
-	[string.char(99)] = string.char(85),
-	[string.char(100)] = string.char(82),
-	[string.char(101)] = string.char(83),
-	[string.char(102)] = string.char(80),
-	[string.char(103)] = string.char(81),
-	[string.char(104)] = string.char(94),
-	[string.char(105)] = string.char(95),
-	[string.char(106)] = string.char(92),
-	[string.char(107)] = string.char(93),
-	[string.char(108)] = string.char(90),
-	[string.char(109)] = string.char(91),
-	[string.char(110)] = string.char(88),
-	[string.char(111)] = string.char(89),
-	[string.char(112)] = string.char(70),
-	[string.char(113)] = string.char(71),
-	[string.char(114)] = string.char(68),
-	[string.char(115)] = string.char(69),
-	[string.char(116)] = string.char(66),
-	[string.char(117)] = string.char(67),
-	[string.char(118)] = string.char(64),
-	[string.char(119)] = string.char(65),
-	[string.char(120)] = string.char(78),
-	[string.char(121)] = string.char(79),
-	[string.char(122)] = string.char(76),
-	[string.char(123)] = string.char(77),
-	[string.char(124)] = string.char(74),
-	[string.char(125)] = string.char(75),
-	[string.char(126)] = string.char(72),
-	[string.char(127)] = string.char(73),
-	[string.char(128)] = string.char(182),
-	[string.char(129)] = string.char(183),
-	[string.char(130)] = string.char(180),
-	[string.char(131)] = string.char(181),
-	[string.char(132)] = string.char(178),
-	[string.char(133)] = string.char(179),
-	[string.char(134)] = string.char(176),
-	[string.char(135)] = string.char(177),
-	[string.char(136)] = string.char(190),
-	[string.char(137)] = string.char(191),
-	[string.char(138)] = string.char(188),
-	[string.char(139)] = string.char(189),
-	[string.char(140)] = string.char(186),
-	[string.char(141)] = string.char(187),
-	[string.char(142)] = string.char(184),
-	[string.char(143)] = string.char(185),
-	[string.char(144)] = string.char(166),
-	[string.char(145)] = string.char(167),
-	[string.char(146)] = string.char(164),
-	[string.char(147)] = string.char(165),
-	[string.char(148)] = string.char(162),
-	[string.char(149)] = string.char(163),
-	[string.char(150)] = string.char(160),
-	[string.char(151)] = string.char(161),
-	[string.char(152)] = string.char(174),
-	[string.char(153)] = string.char(175),
-	[string.char(154)] = string.char(172),
-	[string.char(155)] = string.char(173),
-	[string.char(156)] = string.char(170),
-	[string.char(157)] = string.char(171),
-	[string.char(158)] = string.char(168),
-	[string.char(159)] = string.char(169),
-	[string.char(160)] = string.char(150),
-	[string.char(161)] = string.char(151),
-	[string.char(162)] = string.char(148),
-	[string.char(163)] = string.char(149),
-	[string.char(164)] = string.char(146),
-	[string.char(165)] = string.char(147),
-	[string.char(166)] = string.char(144),
-	[string.char(167)] = string.char(145),
-	[string.char(168)] = string.char(158),
-	[string.char(169)] = string.char(159),
-	[string.char(170)] = string.char(156),
-	[string.char(171)] = string.char(157),
-	[string.char(172)] = string.char(154),
-	[string.char(173)] = string.char(155),
-	[string.char(174)] = string.char(152),
-	[string.char(175)] = string.char(153),
-	[string.char(176)] = string.char(134),
-	[string.char(177)] = string.char(135),
-	[string.char(178)] = string.char(132),
-	[string.char(179)] = string.char(133),
-	[string.char(180)] = string.char(130),
-	[string.char(181)] = string.char(131),
-	[string.char(182)] = string.char(128),
-	[string.char(183)] = string.char(129),
-	[string.char(184)] = string.char(142),
-	[string.char(185)] = string.char(143),
-	[string.char(186)] = string.char(140),
-	[string.char(187)] = string.char(141),
-	[string.char(188)] = string.char(138),
-	[string.char(189)] = string.char(139),
-	[string.char(190)] = string.char(136),
-	[string.char(191)] = string.char(137),
-	[string.char(192)] = string.char(246),
-	[string.char(193)] = string.char(247),
-	[string.char(194)] = string.char(244),
-	[string.char(195)] = string.char(245),
-	[string.char(196)] = string.char(242),
-	[string.char(197)] = string.char(243),
-	[string.char(198)] = string.char(240),
-	[string.char(199)] = string.char(241),
-	[string.char(200)] = string.char(254),
-	[string.char(201)] = string.char(255),
-	[string.char(202)] = string.char(252),
-	[string.char(203)] = string.char(253),
-	[string.char(204)] = string.char(250),
-	[string.char(205)] = string.char(251),
-	[string.char(206)] = string.char(248),
-	[string.char(207)] = string.char(249),
-	[string.char(208)] = string.char(230),
-	[string.char(209)] = string.char(231),
-	[string.char(210)] = string.char(228),
-	[string.char(211)] = string.char(229),
-	[string.char(212)] = string.char(226),
-	[string.char(213)] = string.char(227),
-	[string.char(214)] = string.char(224),
-	[string.char(215)] = string.char(225),
-	[string.char(216)] = string.char(238),
-	[string.char(217)] = string.char(239),
-	[string.char(218)] = string.char(236),
-	[string.char(219)] = string.char(237),
-	[string.char(220)] = string.char(234),
-	[string.char(221)] = string.char(235),
-	[string.char(222)] = string.char(232),
-	[string.char(223)] = string.char(233),
-	[string.char(224)] = string.char(214),
-	[string.char(225)] = string.char(215),
-	[string.char(226)] = string.char(212),
-	[string.char(227)] = string.char(213),
-	[string.char(228)] = string.char(210),
-	[string.char(229)] = string.char(211),
-	[string.char(230)] = string.char(208),
-	[string.char(231)] = string.char(209),
-	[string.char(232)] = string.char(222),
-	[string.char(233)] = string.char(223),
-	[string.char(234)] = string.char(220),
-	[string.char(235)] = string.char(221),
-	[string.char(236)] = string.char(218),
-	[string.char(237)] = string.char(219),
-	[string.char(238)] = string.char(216),
-	[string.char(239)] = string.char(217),
-	[string.char(240)] = string.char(198),
-	[string.char(241)] = string.char(199),
-	[string.char(242)] = string.char(196),
-	[string.char(243)] = string.char(197),
-	[string.char(244)] = string.char(194),
-	[string.char(245)] = string.char(195),
-	[string.char(246)] = string.char(192),
-	[string.char(247)] = string.char(193),
-	[string.char(248)] = string.char(206),
-	[string.char(249)] = string.char(207),
-	[string.char(250)] = string.char(204),
-	[string.char(251)] = string.char(205),
-	[string.char(252)] = string.char(202),
-	[string.char(253)] = string.char(203),
-	[string.char(254)] = string.char(200),
-	[string.char(255)] = string.char(201),
-}
-
--------------------------------------------------------------------------
-
-function sha256.sha256(msg)
-	msg = preproc(msg, #msg)
-	local H = initH256( { })
-	for i = 1, #msg, 64 do digestblock(msg, i, H) end
-	return str2hexa(num2s(H[1], 4) .. num2s(H[2], 4) .. num2s(H[3], 4) .. num2s(H[4], 4) ..
-	num2s(H[5], 4) .. num2s(H[6], 4) .. num2s(H[7], 4) .. num2s(H[8], 4))
-end
-
-function sha256.sha256_binary(msg)
-	return hex_to_binary(sha256.sha256(msg))
-end
-
-function sha256.hmac_sha256(key, text)
-	assert(type(key) == 'string', "key passed to hmac_sha256 should be a string")
-	assert(type(text) == 'string', "text passed to hmac_sha256 should be a string")
-
-	if #key > blocksize then
-		key = sha256.sha256_binary(key)
-	end
-
-	local key_xord_with_0x36 = key:gsub('.', xor_with_0x36) .. string.rep(string.char(0x36), blocksize - #key)
-	local key_xord_with_0x5c = key:gsub('.', xor_with_0x5c) .. string.rep(string.char(0x5c), blocksize - #key)
-
-	return sha256.sha256(key_xord_with_0x5c .. sha256.sha256_binary(key_xord_with_0x36 .. text))
-end
-
-
-return sha256
diff --git a/sign.lua b/sign.lua
index bcb6878..55fde49 100644
--- a/sign.lua
+++ b/sign.lua
@@ -1,32 +1,23 @@
 local sign = {}
 
-local sha256 = require("sha256")
+local hmac = require("hmac")
+local sha2 = require("sha2")
 
-function sign.sign(key, secret, time, host, path, headers, contentSha256, region)
+function sign.sign(key, secret, time, path, headers, region)
         local day = os.date("%Y%m%d", time)
-        local date = os.date("%a, %d %b %Y %H:%M:%S GMT", time)
         local timestamp = os.date("%Y%m%dT%H%M%SZ", time)
-        local dateKey = sha256.hmac_sha256("AWS4" .. secret, day)
-        local dateRegionKey = sha256.hmac_sha256(dateKey, region)
-        local dateRegionSvcKey = sha256.hmac_sha256(dateRegionKey, 's3')
-        local signingKey = sha256.hmac_sha256(dateRegionSvcKey, 'aws4_request')
-        print("DateKey:          " .. dateKey)
-        print("DateRegionKey:    " .. dateRegionKey)
-        print("DateRegionSvcKey: " .. dateRegionSvcKey)
-        print("SigningKey:       " .. signingKey)
-
-        headers["x-amz-content-sha256"] = contentSha256
-        headers["date"] = date
-        headers["host"] = host
+        local dateKey = hmac.hmac("AWS4" .. secret, day, 'buffer')
+        local dateRegionKey = hmac.hmac(dateKey, region, 'buffer')
+        local dateRegionSvcKey = hmac.hmac(dateRegionKey, 's3', 'buffer')
+        local signingKey = hmac.hmac(dateRegionSvcKey, 'aws4_request', 'buffer')
 
         local keys = {}
-        for k in pairs(headers) do
+        for k, v in pairs(headers) do
                 table.insert(keys, k)
         end
         table.sort(keys)
 
         local signedHeaders = ""
-
         local request = "PUT\n" .. path .. "\n"
         for _, k in ipairs(keys) do
                 request = request .. "\n" .. k .. ":" .. headers[k]
@@ -34,15 +25,9 @@ function sign.sign(key, secret, time, host, path, headers, contentSha256, region
         end
         signedHeaders = string.sub(signedHeaders, 2)
 
-        request = request .. "\n\n" .. signedHeaders .. "\n" .. contentSha256
-        print("Request:\n" .. request)
-        print("-------")
-        local stringToSign = "AWS4-HMAC-SHA256\n" .. timestamp  .. "\n" .. day .. "/" .. region .. "/s3/aws4_request\n" .. sha256.sha256(request)
-        print("String to sign:\n" .. stringToSign)
-        print("-------")
-        local signature = sha256.hmac_sha256(signingKey, stringToSign)
-        print("Signature:\n" .. signature)
-        print("-------")
+        request = request .. "\n\n" .. signedHeaders .. "\n" .. (headers["x-amz-content-sha256"])
+        local stringToSign = "AWS4-HMAC-SHA256\n" .. timestamp  .. "\n" .. day .. "/" .. region .. "/s3/aws4_request\n" .. sha2.hash256(request)
+        local signature = hmac.hmac(signingKey, stringToSign, 'hex')
 
         local result = "AWS4-HMAC-SHA256 Credential=" .. key .. "/" .. day .. "/" .. region .. "/s3/aws4_request,SignedHeaders=" .. signedHeaders
         result = result .. ",Signature=" .. signature
diff --git a/start.sh b/start.sh
index 6c6011c..8b81340 100755
--- a/start.sh
+++ b/start.sh
@@ -12,6 +12,8 @@ fi
 
 set -euo pipefail
 : ${S3_BUCKET_NAME:?"S3_BUCKET_NAME must be set"}
+: ${AWS_REGION:?"AWS_REGION must be set"}
+: ${RETURN_URL:?"RETURN_URL must be set"}
 : ${AWS_ACCESS_KEY_ID:?"AWS_ACCESS_KEY_ID must be set or be possible to fetch from meta-data service on AWS"}
 : ${AWS_SECRET_ACCESS_KEY:?"AWS_ACCESS_KEY_ID must be set or be possible to fetch from meta-data service on AWS"}
 
diff --git a/test.lua b/test.lua
index 89e96cb..384da28 100644
--- a/test.lua
+++ b/test.lua
@@ -1,35 +1,33 @@
 lu = require('luaunit')
 local sign = require("sign")
-local sha256 = require("sha256")
+local sha2 = require("sha2")
 
---local key = os.getenv("AWS_ACCESS_KEY_ID")
---local secret = os.getenv("AWS_SECRET_ACCESS_KEY")
-
--- local headers = {["x-amz-acl"] = acl, ["x-amz-date"] = date, ["x-amz-content-sha256"] = "UNSIGNED-PAYLOAD"}
-
-
-function TestPut()
+function TestPutAWSExample()
     local key = "AKIAIOSFODNN7EXAMPLE"
     local secret = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
     local time = os.time({year = 2013, month = 5, day = 24, hour = 0})
-    local headers = {["x-amz-storage-class"] = "REDUCED_REDUNDANCY", ["x-amz-date"] = "20130524T000000Z" }
-    local contentSha256 = sha256.sha256("Welcome to Amazon S3.")
-    local signature = sign.sign(key, secret, time, "examplebucket.s3.amazonaws.com", "/test%24file.text", headers, contentSha256, "us-east-1")
-    print(signature)
+    local date = os.date('%a, %d %b %Y %H:%M:%S GMT', time)
+    local path = "/test%24file.text"
+    local region = "us-east-1"
+    local contentSha256 = sha2.hash256("Welcome to Amazon S3.")
+    local headers = {["x-amz-storage-class"] = "REDUCED_REDUNDANCY", ["x-amz-date"] = "20130524T000000Z", ["x-amz-content-sha256"] = contentSha256, ["host"] = "examplebucket.s3.amazonaws.com", ["date"] = date }
+    local signature = sign.sign(key, secret, time,path, headers, region)
     lu.assertEquals( type(signature), 'string' )
     lu.assertEquals( signature, "AWS4-HMAC-SHA256 Credential=AKIAIOSFODNN7EXAMPLE/20130524/us-east-1/s3/aws4_request,SignedHeaders=date;host;x-amz-content-sha256;x-amz-date;x-amz-storage-class,Signature=98ad721746da40c64f1a55b78f14c238d841ea1380cd77a1b5971af0ece108bd" )
 end
 
-function TestPut2()
-    local key = "AKIAI2BOGUMMDPX2WKSQ"
-    local secret = "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"
-    local time = os.time({year = 2019, month = 6, day = 28, hour = 15, min = 56, sec = 16})
-    local headers = {["x-amz-acl"] = "public-read", ["x-amz-date"] = "20190628T135616Z" }
-    local contentSha256 = sha256.sha256("fluff2")
-    local signature = sign.sign(key, secret, time, "upload.unbound.se.s3-eu-west-1.amazonaws.com", "/20190628/d25f1855e0cab108cb898ca2bebbb35ed228c1134f9d89492f2c705d5b3c6c355767d37a823ccb31", headers, contentSha256, "eu-west-1")
-    print(signature)
+function TestPut()
+    local key = "AKIAIOSFODNN7EXAMPLE"
+    local secret = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
+    local time = os.time({year = 2019, month = 6, day = 28, hour = 23, min = 50, sec = 58})
+    local date = os.date('%a, %d %b %Y %H:%M:%S GMT', time)
+    local path = "/20190628/d98e63986091dc0eb0fa24cff9fffaf17b90c464c2b1f05685bc91e7585267cb0d09c645e69ef2b7"
+    local region = "eu-west-1"
+    local contentSha256 = sha2.hash256("fluff2")
+    local headers = {["x-amz-acl"] = "public-read", ["x-amz-date"] = "20190628T235058Z", ["x-amz-content-sha256"] = contentSha256, ["host"] = "upload.unbound.se.s3-eu-west-1.amazonaws.com", ["date"] = date }
+    local signature = sign.sign(key, secret, time,path, headers, region)
     lu.assertEquals( type(signature), 'string' )
-    lu.assertEquals( signature, "AWS4-HMAC-SHA256 Credential=AKIAI2BOGUMMDPX2WKSQ/20190628/eu-west-1/s3/aws4_request,SignedHeaders=date;host;x-amz-acl;x-amz-content-sha256;x-amz-date,Signature=38683969ed1a023aedbd0e14bf4beae48a6430c6e13c93f59257c5596578721d" )
+    lu.assertEquals( signature, "AWS4-HMAC-SHA256 Credential=AKIAIOSFODNN7EXAMPLE/20190628/eu-west-1/s3/aws4_request,SignedHeaders=date;host;x-amz-acl;x-amz-content-sha256;x-amz-date,Signature=6dd94b1ff7fd29251dbec629b813ea974323aa6509b6a3db94744aef386914af" )
 end
 
 -- class TestSign