summaryrefslogtreecommitdiffstats
path: root/CryptoPP/gf2_32.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'CryptoPP/gf2_32.cpp')
-rw-r--r--CryptoPP/gf2_32.cpp99
1 files changed, 0 insertions, 99 deletions
diff --git a/CryptoPP/gf2_32.cpp b/CryptoPP/gf2_32.cpp
deleted file mode 100644
index ae4874a40..000000000
--- a/CryptoPP/gf2_32.cpp
+++ /dev/null
@@ -1,99 +0,0 @@
-// gf2_32.cpp - written and placed in the public domain by Wei Dai
-
-#include "pch.h"
-#include "misc.h"
-#include "gf2_32.h"
-
-NAMESPACE_BEGIN(CryptoPP)
-
-GF2_32::Element GF2_32::Multiply(Element a, Element b) const
-{
- word32 table[4];
- table[0] = 0;
- table[1] = m_modulus;
- if (a & 0x80000000)
- {
- table[2] = m_modulus ^ (a<<1);
- table[3] = a<<1;
- }
- else
- {
- table[2] = a<<1;
- table[3] = m_modulus ^ (a<<1);
- }
-
-#if CRYPTOPP_FAST_ROTATE(32)
- b = rotrFixed(b, 30U);
- word32 result = table[b&2];
-
- for (int i=29; i>=0; --i)
- {
- b = rotlFixed(b, 1U);
- result = (result<<1) ^ table[(b&2) + (result>>31)];
- }
-
- return (b&1) ? result ^ a : result;
-#else
- word32 result = table[(b>>30) & 2];
-
- for (int i=29; i>=0; --i)
- result = (result<<1) ^ table[((b>>i)&2) + (result>>31)];
-
- return (b&1) ? result ^ a : result;
-#endif
-}
-
-GF2_32::Element GF2_32::MultiplicativeInverse(Element a) const
-{
- if (a <= 1) // 1 is a special case
- return a;
-
- // warning - don't try to adapt this algorithm for another situation
- word32 g0=m_modulus, g1=a, g2=a;
- word32 v0=0, v1=1, v2=1;
-
- assert(g1);
-
- while (!(g2 & 0x80000000))
- {
- g2 <<= 1;
- v2 <<= 1;
- }
-
- g2 <<= 1;
- v2 <<= 1;
-
- g0 ^= g2;
- v0 ^= v2;
-
- while (g0 != 1)
- {
- if (g1 < g0 || ((g0^g1) < g0 && (g0^g1) < g1))
- {
- assert(BitPrecision(g1) <= BitPrecision(g0));
- g2 = g1;
- v2 = v1;
- }
- else
- {
- assert(BitPrecision(g1) > BitPrecision(g0));
- g2 = g0; g0 = g1; g1 = g2;
- v2 = v0; v0 = v1; v1 = v2;
- }
-
- while ((g0^g2) >= g2)
- {
- assert(BitPrecision(g0) > BitPrecision(g2));
- g2 <<= 1;
- v2 <<= 1;
- }
-
- assert(BitPrecision(g0) == BitPrecision(g2));
- g0 ^= g2;
- v0 ^= v2;
- }
-
- return v0;
-}
-
-NAMESPACE_END