1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT LIBRARY COMPONENTS                          --
4--                                                                          --
5--       G N A T . S E C U R E _ H A S H E S . S H A 2 _ C O M M O N        --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--           Copyright (C) 2009-2018, Free Software Foundation, Inc.        --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This package provides supporting code for implementation of the following
33--  secure hash functions described in FIPS PUB 180-3: SHA-224, SHA-256,
34--  SHA-384, SHA-512. It contains the generic transform operation that is
35--  common to the above four functions. The complete text of FIPS PUB 180-3
36--  can be found at:
37--    http://csrc.nist.gov/publications/fips/fips180-3/fips180-3_final.pdf
38
39--  This is an internal unit and should not be used directly in applications.
40--  Use GNAT.SHA* instead.
41
42package GNAT.Secure_Hashes.SHA2_Common is
43
44   Block_Words : constant := 16;
45   --  All functions operate on blocks of 16 words
46
47   generic
48      with package Hash_State is new Hash_Function_State (<>);
49
50      Rounds : Natural;
51      --  Number of transformation rounds
52
53      K : Hash_State.State;
54      --  Constants used in the transform operation
55
56      with function Sigma0 (X : Hash_State.Word) return Hash_State.Word is <>;
57      with function Sigma1 (X : Hash_State.Word) return Hash_State.Word is <>;
58      with function S0 (X : Hash_State.Word) return Hash_State.Word is <>;
59      with function S1 (X : Hash_State.Word) return Hash_State.Word is <>;
60      --  FIPS PUB 180-3 elementary functions
61
62   procedure Transform
63     (H_St : in out Hash_State.State;
64      M_St : in out Message_State);
65
66end GNAT.Secure_Hashes.SHA2_Common;
67