diff -uNr a/vtools/manifest b/vtools/manifest
--- a/vtools/manifest bb7b5cb38ad1749d191b26362c637e55b9abc4a4b689885ececc5c7eea142d86ef56278874b665bb0c14f73819f2857e33f888bcfdc2bde3f3401f241fa566a4
+++ b/vtools/manifest 6e0728447dd05a8e1d4dd21a9647ac87e1e66b16e1cb15dca1a9e775907767fcae8b4db6be152aba863bee3bf15cfb665512a45f001593bfd990b43e4087d3ef
@@ -7,3 +7,4 @@
 517100 phf vtools_fixes_static_tohex Fixes for xalloc's use of static inline courtesy of spyked, fix broken ToHex implementation
 517100 phf vtools_vpatch_newline Vpatch tool support for "No newline at end of file" directive.
 543200 phf vtools_ksum Ksum standalone keccak hasher
+547300 bvt vtools_tempfile_standalone_notmp Standalone temporary file generation code; creates temporary files in the vpatch work directory.
diff -uNr a/vtools/src/temporary_file.adb b/vtools/src/temporary_file.adb
--- a/vtools/src/temporary_file.adb false
+++ b/vtools/src/temporary_file.adb 4747969b6df8aa268419f3259a757d1fee33b8b4a7d440b8adfe07c7f6335060b533791908ff1f5022ecfb51708277a59b0876812c4343e17df1f3f0de0ea767
@@ -0,0 +1,71 @@
+with Bits; use Bits;
+with System; use System;
+with SMG_Keccak; use SMG_Keccak;
+
+package body Temporary_File is
+   -- Create a new file or exit when the file with specified name exists.
+   -- Use fopen(3) with "x" mode to create the file or error out if it
+   -- already exists.
+   subtype File_Ptr is System.Address;
+   subtype C_String is System.Address;
+
+   function fopen (Path: C_String;
+                   Mode: C_String) return File_Ptr;
+   pragma Import (C, fopen);
+
+   procedure fclose (Stream: File_Ptr);
+   pragma Import (C, fclose);
+
+   function Create_File_Exclusive(Path: String) return Boolean is
+      Fptr: File_Ptr;
+   begin
+      declare
+         XP : aliased String := Path & ASCII.NUL;
+         XM : aliased String := "wx" & ASCII.NUL;
+      begin
+         Fptr := fopen(XP'Address, XM'Address);
+      end;
+      if Fptr = System.Null_Address then
+         return False;
+      end if;
+      fclose(Fptr);
+      return True;
+   end Create_File_Exclusive;
+
+   -- Create a temporary file with a randomly generated name;
+   -- if the file with random component F exists, retry with
+   -- H(F) as a new random component.
+   Function Temporary_File(Path_Prefix: String;
+                           Seed: Bitstream) return String is
+      Hash: Bitstream(1..64*8);
+      Name_Ctx: Keccak_Context;
+
+      procedure Hash_Bitstream(Input: Bitstream) is
+      begin
+         KeccakBegin(Name_Ctx);
+         KeccakHash(Name_Ctx, Input);
+         KeccakEnd(Name_Ctx, Hash);
+      end Hash_Bitstream;
+   begin
+      Hash_Bitstream(Seed);
+      loop
+         declare
+            File_Name: String := Path_Prefix & ToHex(Hash);
+         begin
+            if Create_File_Exclusive(File_Name) then
+               return File_Name;
+            end if;
+         end;
+         Hash_Bitstream(Hash);
+      end loop;
+   end Temporary_File;
+
+   function Temporary_File(Path_Prefix: String;
+                           Seed: String) return String is
+      B: Bitstream(1..Seed'Length*8);
+   begin
+      ToBitstream(Seed, B);
+      return Temporary_File(Path_Prefix, B);
+   end Temporary_File;
+
+end Temporary_File;
diff -uNr a/vtools/src/temporary_file.ads b/vtools/src/temporary_file.ads
--- a/vtools/src/temporary_file.ads false
+++ b/vtools/src/temporary_file.ads 94160eed9e9d4daf0b80dea4cc22b8060554e972e84b072ef7b5227dbcde4f5b0367c0706a6885a00f1151a59039a94db196370dfcbe941e352ac8838ea3a03e
@@ -0,0 +1,3 @@
+package Temporary_File is
+   function Temporary_File(Path_Prefix: String; Seed: String) return String;
+end Temporary_File;
diff -uNr a/vtools/src/vpatch.adb b/vtools/src/vpatch.adb
--- a/vtools/src/vpatch.adb 23dcf3c0eff5d5ca20ce1c5091e4dc9b739d2d98630208aa16dec1298a13c28962089c0311e8e50af9801c026e79f003fe8b9ce9341c351cb4e4556347d14734
+++ b/vtools/src/vpatch.adb 11c17fedc3c0442c3ca93589a47f5fdc4b9ab3bab4361a96cbff4bbb15e031d44bfeceed59e5ea6942f552fca67214c3fc9d956779f77b8a0e7432ca609f779f
@@ -1,6 +1,4 @@
 with Bits; use Bits;
-with Interfaces.C;
-with Interfaces.C.Strings;
 with Ada.Text_IO;  use Ada.Text_IO;
 with Ada.Integer_Text_IO; use  Ada.Integer_Text_IO;
 with Character_IO; use Character_IO;
@@ -11,6 +9,7 @@
 with Ada.Characters.Latin_1;
 with Ada.Sequential_IO;
 with SMG_Keccak; use SMG_Keccak;
+with Temporary_File; use Temporary_File;
 
 procedure VPatch is
    package Latin_1 renames Ada.Characters.Latin_1;
@@ -59,36 +58,22 @@
 
    -- Temporary File
 
-   procedure MkTemp(Template: Interfaces.C.Strings.Chars_Ptr);
-   pragma Import(C, mktemp);
-
-   function Temp_File_Name(Template: String) return String is
-      X: Interfaces.C.Strings.Chars_Ptr
-        := Interfaces.C.Strings.New_String(Template);
-   begin
-      MkTemp(X);
-      declare
-         Result: String := Interfaces.C.Strings.Value(X);
-      begin
-         Interfaces.C.Strings.Free(X);
-         return Result;
-      end;
-   end;
-
    procedure Create_Temp(File : in out File_Type;
                          Mode : in File_Mode := Out_File;
-                         Template : in String := "vpatch.XXX";
+                         Prefix : in String;
+                         Seed : in String := "";
                          Form : in String := "") is
-      Name: String := Temp_File_Name(Template);
+      Name: String := Temporary_File.Temporary_File(Prefix, Seed);
    begin
       Create(File, Mode, Name, Form);
    end;
 
    procedure Create_Temp(File : in out CIO.File_Type;
                          Mode : in CIO.File_Mode := CIO.Out_File;
-                         Template : in String := "vpatch.XXX";
+                         Prefix : in String;
+                         Seed : in String := "";
                          Form : in String := "") is
-      Name: String := Temp_File_Name(Template);
+      Name: String := Temporary_File.Temporary_File(Prefix, Seed);
    begin
       Create(File, Mode, Name, Form);
    end;
@@ -466,7 +451,7 @@
 
       -- prepare keccak and open files
       KeccakBegin(To_Ctx);
-      Create_Temp(To_F, Template => "tmp.XXX");
+      Create_Temp(To_F, Prefix => "vpatch-", Seed => To_F_Name);
       case Op is
          when Op_Create =>
             Has_Input_File := False;