diff --git a/nselib/afp.lua b/nselib/afp.lua
index 16c17c5c5..81db01b6c 100644
--- a/nselib/afp.lua
+++ b/nselib/afp.lua
@@ -1846,15 +1846,7 @@ Util =
   -- @param len number containing the length of the new string
   -- @return str string containing the new string
   ZeroPad = function( str, len )
-    if len < str:len() then
-      return
-    end
-
-    for i=1, len - str:len() do
-      str = str .. string.char(0)
-    end
-
-    return str
+    return str .. string.rep('\0', len - str:len())
   end,
 
   --- Splits a path into two pieces, directory and file
diff --git a/nselib/drda.lua b/nselib/drda.lua
index f96d47cfd..5aab6e91e 100644
--- a/nselib/drda.lua
+++ b/nselib/drda.lua
@@ -775,13 +775,7 @@ StringUtil =
   -- @param len the total length of the finished string
   -- @return str string containing the padded string
   padWithChar = function( str, chr, len )
-    if ( len < #str ) then
-      return str
-    end
-    for i=1, (len - #str) do
-      str = str .. chr
-    end
-    return str
+    return str .. string.rep(chr, len - #str)
   end,
 }
 
diff --git a/nselib/iscsi.lua b/nselib/iscsi.lua
index abb735d26..47b3f5cba 100644
--- a/nselib/iscsi.lua
+++ b/nselib/iscsi.lua
@@ -126,8 +126,6 @@ Packet = {
       local pad = 4 - ((#kvps + 48) % 4)
       pad = ( pad == 4 ) and 0 or pad
 
-      for i=1, pad do kvps = kvps .. "\0" end
-
       local len = bit.lshift( self.total_ahs_len, 24 ) + self.data_seg_len
       local flags = bit.lshift( ( self.flags.transit or 0 ), 7 )
       flags = flags + bit.lshift( ( self.flags.continue or 0 ), 6)
@@ -136,12 +134,12 @@ Packet = {
 
       local opcode = self.opcode + bit.lshift((self.immediate or 0), 6)
 
-      local data = bin.pack(">CCCCICSCSSISSIILLA", opcode,
+      local data = bin.pack(">CCCCICSCSSISSIILLAA", opcode,
       flags, self.ver_max, self.ver_min, len,
       bit.lshift( self.isid.t, 6 ) + bit.band( self.isid.a, 0x3f),
       self.isid.b, self.isid.c, self.isid.d, self.tsih,
       self.initiator_task_tag, self.cid, reserved, self.cmdsn,
-      self.expstatsn, reserved, reserved, kvps )
+      self.expstatsn, reserved, reserved, kvps, string.rep('\0', pad) )
 
       return data
     end
@@ -271,7 +269,7 @@ Packet = {
       flags = flags + bit.lshift( (self.flags.continue or 0), 6 )
 
       local kvps = tostring(self.kvp)
-      for i=1, (#kvps % 2) do kvps = kvps .. "\0" end
+      kvps = kvps .. string.rep('\0', #kvps % 2)
       self.data_seg_len = #kvps
 
       local len = bit.lshift( self.total_ahs_len, 24 ) + self.data_seg_len
diff --git a/nselib/msrpctypes.lua b/nselib/msrpctypes.lua
index 72a61321e..084dede57 100644
--- a/nselib/msrpctypes.lua
+++ b/nselib/msrpctypes.lua
@@ -589,7 +589,6 @@ end
 function marshall_ascii(str, max_length)
   local buffer_length
   local result
-  local padding = ""
 
   buffer_length = #str + 1
 
@@ -597,9 +596,7 @@ function marshall_ascii(str, max_length)
     max_length = buffer_length
   end
 
-  while((#(str .. string.char(0 .. padding)) % 4) ~= 0) do
-    padding = padding .. string.char(0)
-  end
+  local padding = string.rep('\0', (4 - (buffer_length % 4)) % 4)
 
   result = bin.pack("<IIIzA",
     max_length,
diff --git a/nselib/ncp.lua b/nselib/ncp.lua
index c808364aa..141a62373 100644
--- a/nselib/ncp.lua
+++ b/nselib/ncp.lua
@@ -1108,9 +1108,7 @@ Util =
   -- @param len number containing the length of the new string
   -- @return str string containing the new string
   ZeroPad = function( str, len )
-    if len < str:len() then return end
-    for i=1, len - str:len() do str = str .. string.char(0) end
-    return str
+    return str .. string.rep('\0', len - #str)
   end,
 
   -- Removes trailing nulls
diff --git a/nselib/netbios.lua b/nselib/netbios.lua
index b028d9929..f199b33d9 100644
--- a/nselib/netbios.lua
+++ b/nselib/netbios.lua
@@ -51,9 +51,7 @@ function name_encode(name, scope)
       padding = "\0"
     end
 
-    repeat
-      name = name .. padding
-    until #name == 16
+    name = name .. string.rep(padding, 16 - #name)
   end
 
   -- Convert to uppercase
diff --git a/nselib/pgsql.lua b/nselib/pgsql.lua
index 88c023f3f..11b9db9ab 100644
--- a/nselib/pgsql.lua
+++ b/nselib/pgsql.lua
@@ -53,15 +53,7 @@ v2 =
   -- @param len number containing the wanted length
   -- @return string containing the padded string value
   zeroPad = function(str, len)
-    local padding = len - str:len()
-
-    if ( padding < 0 ) then
-      return str
-    end
-    for i=1,padding do
-      str = str .. string.char(0x00)
-    end
-    return str
+    return str .. string.rep('\0', len - #str)
   end,
 
   messageDecoder = {
diff --git a/nselib/smb.lua b/nselib/smb.lua
index 3dd112604..cc22a0fa6 100644
--- a/nselib/smb.lua
+++ b/nselib/smb.lua
@@ -2381,10 +2381,7 @@ function send_transaction_waitnamedpipe(smb, priority, pipe, overrides)
     priority                         -- Handle to open file
     )
 
-  while(((#pipe + 1 + #padding) % 4) ~= 0) do
-    padding = padding .. string.char(0)
-  end
-  data = bin.pack("<zA", pipe, padding);
+  data = bin.pack("zA", pipe, string.rep('\0', (4 - ((#pipe+1) % 4)) % 4))
 
   -- Send the transaction request
   stdnse.debug2("SMB: Sending SMB_COM_TRANSACTION (WaitNamedPipe)")
@@ -2763,17 +2760,12 @@ function find_files(smbstate, fname, options)
   local loi   = 260 -- Level of interest, return SMB_FIND_FILE_BOTH_DIRECTORY_INFO
   local storage_type = 0 -- despite the documentation of having to be either 0x01 or 0x40, wireshark reports 0
 
-  local function_parameters = bin.pack("<SSSSIA", nattrs, srch_count, flags, loi, storage_type, fname)
-
   -- SMB header: 32
   -- trans2 header: 36
-  -- FIND_FIRST2 parameters: #function_parameters
-  local pad = ( 32 + 36 + #function_parameters ) % 4
-  if ( pad > 0 ) then
-    for i=1, ( 4-pad ) do
-      function_parameters = function_parameters .. "\0"
-    end
-  end
+  -- FIND_FIRST2 parameters: 12 + #fname
+  local pad = ( 32 + 36 + 12 + #fname ) % 4
+  local function_parameters = bin.pack("<SSSSIAA",
+    nattrs, srch_count, flags, loi, storage_type, fname, string.rep('\0', (4 - pad) % 4))
 
 
   local function next_item()
diff --git a/nselib/tns.lua b/nselib/tns.lua
index 09d16a868..08379a5e9 100644
--- a/nselib/tns.lua
+++ b/nselib/tns.lua
@@ -1456,11 +1456,7 @@ Crypt = {
     local key = bin.pack("H", "0123456789abcdef")
 
     -- do padding
-    if ( #uspw % 8 > 0 ) then
-      for i=1,(8-(#uspw % 8)) do
-        uspw = uspw .. "\0"
-      end
-    end
+    uspw = uspw .. string.rep('\0', (8 - (#uspw % 8)) % 8)
 
     local iv2 = openssl.encrypt( "DES-CBC", key, nil, uspw, false ):sub(-8)
     local enc = openssl.encrypt( "DES-CBC", iv2, nil, uspw, false ):sub(-8)
diff --git a/nselib/vnc.lua b/nselib/vnc.lua
index 2efc7f39b..650ccd5be 100644
--- a/nselib/vnc.lua
+++ b/nselib/vnc.lua
@@ -196,11 +196,7 @@ VNC = {
   -- @param password string containing the password to process
   -- @return password string containing the processed password
   createVNCDESKey = function( self, password )
-    if ( #password < 8 ) then
-      for i=1, (8 - #password) do
-        password = password .. string.char(0x00)
-      end
-    end
+    password = password .. string.rep('\0', 8 - #password)
 
     local newpass = ""
     for i=1, 8 do