Skip to content
GitLab
Menu
Projects
Groups
Snippets
Help
Help
Support
Community forum
Keyboard shortcuts
?
Submit feedback
Contribute to GitLab
Sign in / Register
Toggle navigation
Menu
Open sidebar
Dmitry Baryshkov
nettle
Commits
aecde8cd
Commit
aecde8cd
authored
Jun 20, 2011
by
Niels Möller
Browse files
(SBOX0_INVERSE): Eliminated temporaries.
Rev: nettle/serpent-decrypt.c:1.4
parent
0b166f3c
Changes
1
Show whitespace changes
Inline
Side-by-side
serpent-decrypt.c
View file @
aecde8cd
...
...
@@ -66,33 +66,49 @@
(GPL), although some comments in the code still say otherwise. You
are welcome to use Serpent for any application." */
/* FIXME: Except when used within the key schedule, the inputs are not
used after the substitution, and hence we could allow them to be
destroyed. Can this freedom be used to optimize the sboxes? */
/* Original single-assignment form:
t01 = x2 ^ x3;
t02 = x0 | x1;
t03 = x1 | x2;
t04 = x2 & t01;
t05 = t02 ^ t01;
t06 = x0 | t04;
y2 = ~ t05;
t08 = x1 ^ x3;
t09 = t03 & t08;
t10 = x3 | y2;
y1 = t09 ^ t06;
t12 = x0 | t05;
t13 = y1 ^ t12;
t14 = t03 ^ t10;
t15 = x0 ^ x2;
y3 = t14 ^ t13;
t17 = t05 & t13;
t18 = t14 | t17;
y0 = t15 ^ t18;
*/
#define SBOX0_INVERSE(type, x0, x1, x2, x3, y0, y1, y2, y3) \
do { \
type t02, t03, t04, t05, t06, t08, t09, t10; \
type t12, t13, t14, t15, t17, t18, t01; \
t01 = x2 ^ x3; \
t02 = x0 | x1; \
t03 = x1 | x2; \
t04 = x2 & t01; \
t05 = t02 ^ t01; \
t06 = x0 | t04; \
y2 = ~ t05; \
t08 = x1 ^ x3; \
t09 = t03 & t08; \
t10 = x3 | y2; \
y1 = t09 ^ t06; \
t12 = x0 | t05; \
t13 = y1 ^ t12; \
t14 = t03 ^ t10; \
t15 = x0 ^ x2; \
y3 = t14 ^ t13; \
t17 = t05 & t13; \
t18 = t14 | t17; \
y0 = t15 ^ t18; \
y0 = x0 ^ x2; \
y2 = x0 | x1; \
y1 = x2 ^ x3; \
y2 ^= y1; \
y1 &= x2; \
x2 |= x1; \
x1 ^= x3; \
y1 |= x0; \
x1 &= x2; \
y1 ^= x1; \
x0 |= y2; \
x0 ^= y1; \
x1 = y2 & x0; \
y2 = ~ y2; \
x3 |= y2; \
x3 ^= x2; \
y3 = x3 ^ x0; \
x1 |= x3; \
y0 ^= x1; \
} while (0)
#define SBOX1_INVERSE(type, x0, x1, x2, x3, y0, y1, y2, y3) \
...
...
Write
Preview
Markdown
is supported
0%
Try again
or
attach a new file
.
Attach a file
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Cancel
Please
register
or
sign in
to comment