From 3438e5d3ddf8444f0e31009ffbe8237ef3752c22 Mon Sep 17 00:00:00 2001 From: Alexander Harkness Date: Sun, 24 Nov 2013 14:21:13 +0000 Subject: move cryptopp into lib --- lib/cryptopp/gf256.cpp | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 lib/cryptopp/gf256.cpp (limited to 'lib/cryptopp/gf256.cpp') diff --git a/lib/cryptopp/gf256.cpp b/lib/cryptopp/gf256.cpp new file mode 100644 index 000000000..72026d1e1 --- /dev/null +++ b/lib/cryptopp/gf256.cpp @@ -0,0 +1,34 @@ +// gf256.cpp - written and placed in the public domain by Wei Dai + +#include "pch.h" +#include "gf256.h" + +NAMESPACE_BEGIN(CryptoPP) + +GF256::Element GF256::Multiply(Element a, Element b) const +{ + word result = 0, t = b; + + for (unsigned int i=0; i<8; i++) + { + result <<= 1; + if (result & 0x100) + result ^= m_modulus; + + t <<= 1; + if (t & 0x100) + result ^= a; + } + + return (GF256::Element) result; +} + +GF256::Element GF256::MultiplicativeInverse(Element a) const +{ + Element result = a; + for (int i=1; i<7; i++) + result = Multiply(Square(result), a); + return Square(result); +} + +NAMESPACE_END -- cgit v1.2.3