1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
------------------------------------------------------------------------------
-- --
-- GNAT LIBRARY COMPONENTS --
-- --
-- G N A T . S E C U R E _ H A S H E S . S H A 1 --
-- --
-- B o d y --
-- --
-- Copyright (C) 2002-2009, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
package body GNAT.Secure_Hashes.SHA1 is
use Interfaces;
use GNAT.Byte_Swapping;
-- The following functions are the four elementary components of each
-- of the four round groups (0 .. 19, 20 .. 39, 40 .. 59, and 60 .. 79)
-- defined in RFC 3174.
function F0 (B, C, D : Unsigned_32) return Unsigned_32;
pragma Inline (F0);
function F1 (B, C, D : Unsigned_32) return Unsigned_32;
pragma Inline (F1);
function F2 (B, C, D : Unsigned_32) return Unsigned_32;
pragma Inline (F2);
function F3 (B, C, D : Unsigned_32) return Unsigned_32;
pragma Inline (F3);
--------
-- F0 --
--------
function F0
(B, C, D : Interfaces.Unsigned_32) return Interfaces.Unsigned_32
is
begin
return (B and C) or ((not B) and D);
end F0;
--------
-- F1 --
--------
function F1
(B, C, D : Interfaces.Unsigned_32) return Interfaces.Unsigned_32
is
begin
return B xor C xor D;
end F1;
--------
-- F2 --
--------
function F2
(B, C, D : Interfaces.Unsigned_32) return Interfaces.Unsigned_32
is
begin
return (B and C) or (B and D) or (C and D);
end F2;
--------
-- F3 --
--------
function F3
(B, C, D : Interfaces.Unsigned_32) return Interfaces.Unsigned_32
renames F1;
---------------
-- Transform --
---------------
procedure Transform
(H : in out Hash_State.State;
M : in out Message_State)
is
use System;
type Words is array (Natural range <>) of Interfaces.Unsigned_32;
X : Words (0 .. 15);
for X'Address use M.Buffer'Address;
pragma Import (Ada, X);
W : Words (0 .. 79);
A, B, C, D, E, Temp : Interfaces.Unsigned_32;
begin
if Default_Bit_Order /= High_Order_First then
for J in X'Range loop
Swap4 (X (J)'Address);
end loop;
end if;
-- a. Divide data block into sixteen words
W (0 .. 15) := X;
-- b. Prepare working block of 80 words
for T in 16 .. 79 loop
-- W(t) = S^1(W(t-3) XOR W(t-8) XOR W(t-14) XOR W(t-16))
W (T) := Rotate_Left
(W (T - 3) xor W (T - 8) xor W (T - 14) xor W (T - 16), 1);
end loop;
-- c. Set up transformation variables
A := H (0);
B := H (1);
C := H (2);
D := H (3);
E := H (4);
-- d. For each of the 80 rounds, compute:
-- TEMP = S^5(A) + f(t;B,C,D) + E + W(t) + K(t);
-- E = D; D = C; C = S^30(B); B = A; A = TEMP;
for T in 0 .. 19 loop
Temp := Rotate_Left (A, 5) + F0 (B, C, D) + E + W (T) + 16#5A827999#;
E := D; D := C; C := Rotate_Left (B, 30); B := A; A := Temp;
end loop;
for T in 20 .. 39 loop
Temp := Rotate_Left (A, 5) + F1 (B, C, D) + E + W (T) + 16#6ED9EBA1#;
E := D; D := C; C := Rotate_Left (B, 30); B := A; A := Temp;
end loop;
for T in 40 .. 59 loop
Temp := Rotate_Left (A, 5) + F2 (B, C, D) + E + W (T) + 16#8F1BBCDC#;
E := D; D := C; C := Rotate_Left (B, 30); B := A; A := Temp;
end loop;
for T in 60 .. 79 loop
Temp := Rotate_Left (A, 5) + F3 (B, C, D) + E + W (T) + 16#CA62C1D6#;
E := D; D := C; C := Rotate_Left (B, 30); B := A; A := Temp;
end loop;
-- e. Update context:
-- H0 = H0 + A, H1 = H1 + B, H2 = H2 + C, H3 = H3 + D, H4 = H4 + E
H (0) := H (0) + A;
H (1) := H (1) + B;
H (2) := H (2) + C;
H (3) := H (3) + D;
H (4) := H (4) + E;
end Transform;
end GNAT.Secure_Hashes.SHA1;
|
