diff --git a/nselib/ajp.lua b/nselib/ajp.lua
index 7d8c2ffcc..cc4822123 100644
--- a/nselib/ajp.lua
+++ b/nselib/ajp.lua
@@ -1,9 +1,9 @@
 local base64 = require "base64"
-local bin = require "bin"
 local http = require "http"
 local match = require "match"
 local nmap = require "nmap"
 local stdnse = require "stdnse"
+local string = require "string"
 local table = require "table"
 local url = require "url"
 _ENV = stdnse.module("ajp", stdnse.seeall)
@@ -127,9 +127,9 @@ AJP = {
       -- as the zero terminator should not be counted in the length
       local function encstr(str)
         if ( not(str) or #str == 0 ) then
-          return bin.pack(">S", 0xFFFF)
+          return "\xFF\xFF"
         end
-        return bin.pack(">Sz", #str, str)
+        return string.pack(">I2z", #str, str)
       end
 
       -- count the number of headers
@@ -152,35 +152,37 @@ AJP = {
       local p_url = url.parse(self.uri)
 
       -- save the magic and data for last
-      local data = bin.pack(">CCAAAAASCS", self.code, self.method,
+      local data = {
+        string.pack(">BB", self.code, self.method),
         encstr(self.version), encstr(p_url.path), encstr(self.raddr),
         encstr(self.rhost), encstr(self.srv),
-        self.port, (self.is_ssl and 1 or 0),
-        headerCount())
+        string.pack(">I2BI2",  self.port, (self.is_ssl and 1 or 0), headerCount()),
+      }
 
       -- encode headers
       for k, v in pairs(self.headers) do
         local header = AJP.ForwardRequest.Header[k:lower()] or k
         if ( "string" == type(header) ) then
-          data = data .. bin.pack(">Sz", #header, header)
+          data[#data+1] = string.pack(">I2z", #header, header)
         else
-          data = data .. bin.pack(">S", header)
+          data[#data+1] = string.pack(">I2", header)
         end
 
-        data = data .. encstr(v)
+        data[#data+1] = encstr(v)
       end
 
       -- encode attributes
       if ( p_url.query ) then
-        data = data .. bin.pack("C", AJP.Attribute.QUERY_STRING)
-        data = data .. encstr(p_url.query)
+        data[#data+1] = string.pack("B", AJP.Attribute.QUERY_STRING)
+        data[#data+1] = encstr(p_url.query)
       end
 
       -- terminate the attribute list
-      data = data .. bin.pack("C", AJP.Attribute.ARE_DONE)
+      data[#data+1] = string.pack("B", AJP.Attribute.ARE_DONE)
 
       -- returns the AJP request as a string
-      return bin.pack(">SSA", AJP.Magic, #data, data)
+      data = table.concat(data)
+      return string.pack(">I2s2", AJP.Magic, data)
     end,
 
   },
@@ -215,12 +217,11 @@ AJP = {
         local pos = 6
         local status_msg, hdr_count
 
-        pos, sh.status = bin.unpack(">S", data, pos)
-        pos, status_msg  = bin.unpack(">P", data, pos)
+        sh.status, status_msg, pos = string.unpack(">I2s2", data, pos)
         pos = pos + 1
         sh.status_line = ("AJP/1.3 %d %s"):format(sh.status, status_msg)
 
-        pos, hdr_count = bin.unpack(">S", data, pos)
+        hdr_count, pos = string.unpack(">I2", data, pos)
 
         local function headerById(id)
           for k, v in pairs(AJP.Response.Header) do
@@ -231,16 +232,16 @@ AJP = {
 
         for i=1, hdr_count do
           local key, val, len
-          pos, len = bin.unpack(">S", data, pos)
+          len, pos = string.unpack(">I2", data, pos)
 
           if ( len < 0xA000 ) then
-            pos, key = bin.unpack("A"..len, data, pos)
+            key, pos = string.unpack("c"..len, data, pos)
             pos = pos + 1
           else
             key = headerById(len)
           end
 
-          pos, val = bin.unpack(">P", data, pos)
+          val, pos = string.unpack(">s2", data, pos)
           pos = pos + 1
 
           sh.headers[key:lower()] = val
@@ -316,7 +317,7 @@ Comm = {
       if ( not(status) ) then
         return false, "Failed to receive response from server"
       end
-      local pos, magic, length = bin.unpack(">A2S", buf)
+      local magic, length, pos = string.unpack(">c2I2", buf)
       if ( magic ~= "AB" ) then
         return false, ("Invalid magic received from server (%s)"):format(magic)
       end
@@ -325,12 +326,12 @@ Comm = {
         return false, "Failed to receive response from server"
       end
 
-      local pos, code = bin.unpack("C", data)
+      local code, pos = string.unpack("B", data)
       if ( AJP.Code.SEND_HEADERS == code ) then
         local sh = AJP.Response.SendHeaders.parse(buf .. data)
         response = sh
       elseif( AJP.Code.SEND_BODY == code ) then
-        response.body = select(2, bin.unpack(">P", data, pos))
+        response.body = string.unpack(">s2", data, pos)
       elseif( AJP.Code.END_RESPONSE == code ) then
         break
       end
diff --git a/nselib/natpmp.lua b/nselib/natpmp.lua
index 9222c33b2..93c46478e 100644
--- a/nselib/natpmp.lua
+++ b/nselib/natpmp.lua
@@ -6,11 +6,11 @@
 --
 -- @author Patrik Karlsson <patrik@cqure.net>
 --
-local bin = require "bin"
 local datetime = require "datetime"
 local ipOps = require "ipOps"
 local nmap = require "nmap"
 local stdnse = require "stdnse"
+local string = require "string"
 _ENV = stdnse.module("natpmp", stdnse.seeall)
 
 local ResultCode = {
@@ -43,7 +43,7 @@ Request = {
     end,
 
     __tostring = function(self)
-      return bin.pack(">CC", self.version, self.op)
+      return string.pack(">BB", self.version, self.op)
     end,
 
   },
@@ -65,7 +65,7 @@ Request = {
     end,
 
     __tostring = function(self)
-      return bin.pack(">CCSSSI",
+      return string.pack(">BBI2I2I2I4",
         self.version,
         (self.proto=="udp" and 1 or 2),
         0, -- reserved
@@ -96,13 +96,13 @@ Response = {
       end
 
       local pos
-      pos, self.version, self.op, self.rescode = bin.unpack(">CCS", self.data)
+      self.version, self.op, self.rescode, pos = string.unpack(">BBI2", self.data)
 
       if ( self.rescode ~= ResultCode.SUCCESS or self.op ~= 128 ) then
         return
       end
 
-      pos, self.time, self.ip = bin.unpack(">II", self.data, pos)
+      self.time, self.ip, pos = string.unpack(">I4I4", self.data, pos)
       self.ip = ipOps.fromdword(self.ip)
       self.time = datetime.format_timestamp(self.time)
       return true
@@ -127,13 +127,13 @@ Response = {
       end
 
       local pos
-      pos, self.version, self.op, self.rescode = bin.unpack(">CCS", self.data)
+      self.version, self.op, self.rescode, pos = string.unpack(">BBI2", self.data)
 
       if ( self.rescode ~= ResultCode.SUCCESS ) then
         return
       end
 
-      pos, self.time, self.privport, self.pubport, self.lifetime = bin.unpack(">ISSI", self.data, pos)
+      self.time, self.privport, self.pubport, self.lifetime, pos = string.unpack(">I4I2I2I4", self.data, pos)
       return true
     end,
   }
diff --git a/nselib/netbios.lua b/nselib/netbios.lua
index 13d3a3d50..fabab8e5d 100644
--- a/nselib/netbios.lua
+++ b/nselib/netbios.lua
@@ -5,7 +5,6 @@
 -- @author Ron Bowes <ron@skullsecurity.net>
 -- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
 
-local bin = require "bin"
 local dns = require "dns"
 local math = require "math"
 local nmap = require "nmap"
@@ -316,14 +315,14 @@ function do_nbstat(host)
   end
 
   -- Create the query header
-  local query = bin.pack(">SSSSSS",
+  local query = string.pack(">I2I2I2I2I2I2",
   0x1337,  -- Transaction id
   0x0000,  -- Flags
   1,       -- Questions
   0,       -- Answers
   0,       -- Authority
   0        -- Extra
-  ) .. bin.pack(">zSS",
+  ) .. string.pack(">zI2I2",
   encoded_name, -- Encoded name
   0x0021,       -- Query type (0x21 = NBSTAT)
   0x0001        -- Class = IN
@@ -354,7 +353,7 @@ function do_nbstat(host)
     local pos, TRN_ID, FLAGS, QDCOUNT, ANCOUNT, NSCOUNT, ARCOUNT, rr_name, rr_type, rr_class, rr_ttl
     local rrlength, name_count
 
-    pos, TRN_ID, FLAGS, QDCOUNT, ANCOUNT, NSCOUNT, ARCOUNT = bin.unpack(">SSSSSS", result)
+    TRN_ID, FLAGS, QDCOUNT, ANCOUNT, NSCOUNT, ARCOUNT, pos = string.unpack(">I2I2I2I2I2I2", result)
 
     -- Sanity check the result (has to have the same TRN_ID, 1 answer, and proper flags)
     if(TRN_ID ~= 0x1337) then
@@ -371,7 +370,7 @@ function do_nbstat(host)
     end
 
     -- Start parsing the answer field
-    pos, rr_name, rr_type, rr_class, rr_ttl = bin.unpack(">zSSI", result, pos)
+    rr_name, rr_type, rr_class, rr_ttl, pos = string.unpack(">zI2I2I4", result, pos)
 
     -- More sanity checks
     if(rr_name ~= encoded_name) then
@@ -384,7 +383,7 @@ function do_nbstat(host)
       return false, "Server returned incorrect query type"
     end
 
-    pos, rrlength, name_count = bin.unpack(">SC", result, pos)
+    rrlength, name_count, pos = string.unpack(">I2B", result, pos)
 
     local names = {}
     for i = 1, name_count do
@@ -392,7 +391,7 @@ function do_nbstat(host)
 
       -- Instead of reading the 16-byte name and pulling off the suffix,
       -- we read the first 15 bytes and then the 1-byte suffix.
-      pos, name, suffix, flags = bin.unpack(">A15CS", result, pos)
+      name, suffix, flags, pos = string.unpack(">c15BI2", result, pos)
       name = string.gsub(name, "[ ]*$", "")
 
       names[i] = {}
@@ -407,7 +406,7 @@ function do_nbstat(host)
     if(rrlength > 0) then
       rrlength = rrlength - 1
     end
-    pos, statistics = bin.unpack(string.format(">A%d", rrlength), result, pos)
+    statistics, pos = string.unpack(string.format(">c%d", rrlength), result, pos)
 
     -- Put it in the registry, in case anybody else needs it
     reg["nbstat_names"] = names
diff --git a/nselib/nrpc.lua b/nselib/nrpc.lua
index 0653c40ef..d5af8a63c 100644
--- a/nselib/nrpc.lua
+++ b/nselib/nrpc.lua
@@ -38,7 +38,6 @@
 --
 
 
-local bin = require "bin"
 local match = require "match"
 local nmap = require "nmap"
 local stdnse = require "stdnse"
@@ -67,14 +66,14 @@ DominoPacket = {
   -- @return Error code (if status is false).
   read = function( self, domsock )
     local status, data = domsock:receive_buf(match.numbytes(2), true)
-    local pos, len = bin.unpack( "<S", data )
+    local len = string.unpack( "<I2", data )
 
     return domsock:receive_buf(match.numbytes(len), true)
   end,
 
   --- converts the packet to a string
   __tostring = function(self)
-    return bin.pack("<SA", #self.data, self.data )
+    return string.pack("<s2", self.data )
   end,
 
 }
@@ -124,7 +123,7 @@ Helper = {
   isValidUser = function( self, username )
     local data = stdnse.fromhex("00001e00000001000080000007320000700104020000fb2b2d00281f1e000000124c010000000000")
     local status, id_data
-    local data_len, pos, total_len, pkt_type, valid_user
+    local data_len, total_len, pkt_type, valid_user
 
     self.domsock:send( tostring(DominoPacket:new( data )) )
     data = DominoPacket:new():read( self.domsock )
@@ -137,9 +136,9 @@ Helper = {
     self.domsock:send( tostring(DominoPacket:new( data ) ) )
     status, id_data = DominoPacket:new():read( self.domsock )
 
-    pos, pkt_type = bin.unpack("C", id_data, 3)
-    pos, valid_user = bin.unpack("C", id_data, 11)
-    pos, total_len = bin.unpack("<S", id_data, 13)
+    pkt_type = string.unpack("B", id_data, 3)
+    valid_user = string.unpack("B", id_data, 11)
+    total_len = string.unpack("<I2", id_data, 13)
 
     if ( pkt_type == 0x16 ) then
       if ( valid_user == 0x19 ) then
diff --git a/nselib/tftp.lua b/nselib/tftp.lua
index d1bbddd38..c34d2af17 100644
--- a/nselib/tftp.lua
+++ b/nselib/tftp.lua
@@ -27,11 +27,11 @@
 --
 -- 2011-01-22 - re-wrote library to use coroutines instead of new_thread code.
 
-local bin = require "bin"
 local coroutine = require "coroutine"
 local nmap = require "nmap"
 local os = require "os"
 local stdnse = require "stdnse"
+local string = require "string"
 local table = require "table"
 _ENV = stdnse.module("tftp", stdnse.seeall)
 
@@ -67,7 +67,7 @@ Packet = {
     end,
 
     __tostring = function( self )
-      return bin.pack(">SS", OpCode.ACK, self.block)
+      return string.pack(">I2I2", OpCode.ACK, self.block)
     end,
 
   },
@@ -85,7 +85,7 @@ Packet = {
     end,
 
     __tostring = function( self )
-      return bin.pack(">SSz", OpCode.ERROR, self.code, self.msg)
+      return string.pack(">I2I2z", OpCode.ERROR, self.code, self.msg)
     end,
   }
 
@@ -168,7 +168,7 @@ end
 -- @param port containing the port of the initiating host
 -- @param data string containing the initial data passed to the server
 local function processConnection( host, port, data )
-  local pos, op = bin.unpack(">S", data)
+  local op, pos = string.unpack(">I2", data)
   local socket = nmap.new_socket("udp")
 
   socket:set_timeout(1000)
@@ -183,7 +183,7 @@ local function processConnection( host, port, data )
     socket:send( tostring(Packet.ERROR:new(0, "TFTP server has write-only support")))
   end
 
-  local pos, filename, enctype = bin.unpack("zz", data, pos)
+  local filename, enctype, pos = string.unpack("zz", data, pos)
   status, err = socket:send( tostring( Packet.ACK:new(0) ) )
 
   local blocks = {}
@@ -201,13 +201,13 @@ local function processConnection( host, port, data )
     else
       -- record last time we had a successful read
       lastread = os.time()
-      pos, op = bin.unpack(">S", pdata)
+      op, pos = string.unpack(">I2", pdata)
       if ( OpCode.DATA ~= op ) then
         stdnse.debug1("Expected a data packet, terminating TFTP transfer")
       end
 
       local block, data
-      pos, block, data = bin.unpack(">SA" .. #pdata - 4, pdata, pos )
+      block, data, pos = string.unpack(">I2 c" .. #pdata - 4, pdata, pos )
 
       blocks[block] = data