diff options
| author | Niels Möller <nisse@lysator.liu.se> | 2011-06-20 22:15:26 +0200 |
|---|---|---|
| committer | Niels Möller <nisse@lysator.liu.se> | 2011-06-20 22:15:26 +0200 |
| commit | 05117bb34bb60d34aa055b8e466758e4e10ffa48 (patch) | |
| tree | e1628b7168cc03812763afe754475205241e963e /serpent-decrypt.c | |
| parent | 671c3e17d3dcfc9a228c7276022238ce7ab91dee (diff) | |
| download | nettle-05117bb34bb60d34aa055b8e466758e4e10ffa48.tar.gz | |
(SBOX2_INVERSE): Eliminated temporaries.
Rev: nettle/serpent-decrypt.c:1.6
Diffstat (limited to 'serpent-decrypt.c')
| -rw-r--r-- | serpent-decrypt.c | 63 |
1 files changed, 41 insertions, 22 deletions
diff --git a/serpent-decrypt.c b/serpent-decrypt.c index 460e9861..4ca7ffcd 100644 --- a/serpent-decrypt.c +++ b/serpent-decrypt.c @@ -155,28 +155,47 @@ y0 ^= x0; \ } while (0) -#define SBOX2_INVERSE(type, x0, x1, x2, x3, y0, y1, y2, y3) \ - do { \ - type t02, t03, t04, t06, t07, t08, t09; \ - type t10, t11, t12, t15, t16, t17, t01; \ - t01 = x0 ^ x3; \ - t02 = x2 ^ x3; \ - t03 = x0 & x2; \ - t04 = x1 | t02; \ - y0 = t01 ^ t04; \ - t06 = x0 | x2; \ - t07 = x3 | y0; \ - t08 = ~ x3; \ - t09 = x1 & t06; \ - t10 = t08 | t03; \ - t11 = x1 & t07; \ - t12 = t06 & t02; \ - y3 = t09 ^ t10; \ - y1 = t12 ^ t11; \ - t15 = x2 & y3; \ - t16 = y0 ^ y1; \ - t17 = t10 ^ t15; \ - y2 = t16 ^ t17; \ +/* S2 inverse: 12 9 15 4 11 14 1 2 0 3 6 13 5 8 10 7 */ +/* Original single-assignment form: + t01 = x0 ^ x3; + t02 = x2 ^ x3; + t03 = x0 & x2; + t04 = x1 | t02; + y0 = t01 ^ t04; + t06 = x0 | x2; + t07 = x3 | y0; + t08 = ~ x3; + t09 = x1 & t06; + t10 = t08 | t03; + t11 = x1 & t07; + t12 = t06 & t02; + y3 = t09 ^ t10; + y1 = t12 ^ t11; + t15 = x2 & y3; + t16 = y0 ^ y1; + t17 = t10 ^ t15; + y2 = t16 ^ t17; +*/ +#define SBOX2_INVERSE(type, x0, x1, x2, x3, y0, y1, y2, y3) \ + do { \ + y0 = x0 ^ x3; \ + y2 = x2 ^ x3; \ + y1 = x1 | y2; \ + y0 ^= y1; \ + y1 = x3 | y0; \ + y1 &= x1; \ + x3 = ~ x3; \ + y3 = x0 | x2; \ + y2 &= y3; \ + y1 ^= y2; \ + y3 &= x1; \ + x0 &= x2; \ + x0 |= x3; \ + y3 ^= x0; \ + x2 &= y3; \ + x2 ^= x0; \ + y2 = y0 ^ y1; \ + y2 ^= x2; \ } while (0) #define SBOX3_INVERSE(type, x0, x1, x2, x3, y0, y1, y2, y3) \ |