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 _ 3 2            --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--           Copyright (C) 2009, 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 support for the 32-bit FIPS PUB 180-3 functions
33--  SHA-224 and SHA-256.
34
35--  This is an internal unit and should not be used directly in applications.
36--  Use GNAT.SHA224 and GNAT.SHA256 instead.
37
38with Interfaces;
39with GNAT.Byte_Swapping;
40with GNAT.Secure_Hashes.SHA2_Common;
41
42package GNAT.Secure_Hashes.SHA2_32 is
43
44   subtype Word is Interfaces.Unsigned_32;
45
46   package Hash_State is new Hash_Function_State
47     (Word           => Word,
48      Swap           => GNAT.Byte_Swapping.Swap4,
49      Hash_Bit_Order => System.High_Order_First);
50   --  SHA-224 and SHA-256 operate on 32-bit big endian words
51
52   K : constant Hash_State.State (0 .. 63) :=
53         (16#428a2f98#, 16#71374491#, 16#b5c0fbcf#, 16#e9b5dba5#,
54          16#3956c25b#, 16#59f111f1#, 16#923f82a4#, 16#ab1c5ed5#,
55          16#d807aa98#, 16#12835b01#, 16#243185be#, 16#550c7dc3#,
56          16#72be5d74#, 16#80deb1fe#, 16#9bdc06a7#, 16#c19bf174#,
57          16#e49b69c1#, 16#efbe4786#, 16#0fc19dc6#, 16#240ca1cc#,
58          16#2de92c6f#, 16#4a7484aa#, 16#5cb0a9dc#, 16#76f988da#,
59          16#983e5152#, 16#a831c66d#, 16#b00327c8#, 16#bf597fc7#,
60          16#c6e00bf3#, 16#d5a79147#, 16#06ca6351#, 16#14292967#,
61          16#27b70a85#, 16#2e1b2138#, 16#4d2c6dfc#, 16#53380d13#,
62          16#650a7354#, 16#766a0abb#, 16#81c2c92e#, 16#92722c85#,
63          16#a2bfe8a1#, 16#a81a664b#, 16#c24b8b70#, 16#c76c51a3#,
64          16#d192e819#, 16#d6990624#, 16#f40e3585#, 16#106aa070#,
65          16#19a4c116#, 16#1e376c08#, 16#2748774c#, 16#34b0bcb5#,
66          16#391c0cb3#, 16#4ed8aa4a#, 16#5b9cca4f#, 16#682e6ff3#,
67          16#748f82ee#, 16#78a5636f#, 16#84c87814#, 16#8cc70208#,
68          16#90befffa#, 16#a4506ceb#, 16#bef9a3f7#, 16#c67178f2#);
69   --  Constants from FIPS PUB 180-3
70
71   function Sigma0 (X : Word) return Word;
72   function Sigma1 (X : Word) return Word;
73   function S0 (X : Word) return Word;
74   function S1 (X : Word) return Word;
75   pragma Inline (Sigma0, Sigma1, S0, S1);
76   --  Elementary functions Sigma^256_0, Sigma^256_1, sigma^256_0, sigma^256_1
77   --  from FIPS PUB 180-3.
78
79   procedure Transform is new SHA2_Common.Transform
80     (Hash_State => Hash_State,
81      K          => K,
82      Rounds     => 64,
83      Sigma0     => Sigma0,
84      Sigma1     => Sigma1,
85      S0         => S0,
86      S1         => S1);
87
88   SHA224_Init_State : constant Hash_State.State (0 .. 7) :=
89                         (0 => 16#c1059ed8#,
90                          1 => 16#367cd507#,
91                          2 => 16#3070dd17#,
92                          3 => 16#f70e5939#,
93                          4 => 16#ffc00b31#,
94                          5 => 16#68581511#,
95                          6 => 16#64f98fa7#,
96                          7 => 16#befa4fa4#);
97   SHA256_Init_State : constant Hash_State.State (0 .. 7) :=
98                         (0 => 16#6a09e667#,
99                          1 => 16#bb67ae85#,
100                          2 => 16#3c6ef372#,
101                          3 => 16#a54ff53a#,
102                          4 => 16#510e527f#,
103                          5 => 16#9b05688c#,
104                          6 => 16#1f83d9ab#,
105                          7 => 16#5be0cd19#);
106   --  Initialization vectors from FIPS PUB 180-3
107
108end GNAT.Secure_Hashes.SHA2_32;
109