25'ten fazla konu seçemezsiniz
Konular bir harf veya rakamla başlamalı, kısa çizgiler ('-') içerebilir ve en fazla 35 karakter uzunluğunda olabilir.
133 satır
2.8 KiB
133 satır
2.8 KiB
#pragma once
|
|
#include <stdint.h>
|
|
#include <stddef.h>
|
|
#include <algorithm>
|
|
#include <array>
|
|
|
|
template<typename word_t>
|
|
size_t lg(word_t v);
|
|
|
|
|
|
/**
|
|
Sean Eron Anderson
|
|
seander@cs.stanford.edu
|
|
**/
|
|
template<>
|
|
size_t lg<uint32_t>(uint32_t v)
|
|
{
|
|
static const int MultiplyDeBruijnBitPosition[32] =
|
|
{
|
|
0, 9, 1, 10, 13, 21, 2, 29, 11, 14, 16, 18, 22, 25, 3, 30,
|
|
8, 12, 20, 28, 15, 17, 24, 7, 19, 27, 23, 6, 26, 5, 4, 31
|
|
};
|
|
|
|
v |= v >> 1;
|
|
v |= v >> 2;
|
|
v |= v >> 4;
|
|
v |= v >> 8;
|
|
v |= v >> 16;
|
|
|
|
return MultiplyDeBruijnBitPosition[(uint32_t)(v * 0x07C4ACDDU) >> 27];
|
|
}
|
|
template<>
|
|
size_t lg<uint64_t>(uint64_t v)
|
|
{
|
|
static const int MultiplyDeBruijnBitPosition[64] =
|
|
{
|
|
0, 58, 1, 59, 47, 53, 2, 60, 39, 48, 27, 54, 33, 42, 3, 61,
|
|
51, 37, 40, 49, 18, 28, 20, 55, 30, 34, 11, 43, 14, 22, 4, 62,
|
|
57, 46, 52, 38, 26, 32, 41, 50, 36, 17, 19, 29, 10, 13, 21, 56,
|
|
45, 25, 31, 35, 16, 9, 12, 44, 24, 15, 8, 23, 7, 6, 5, 63
|
|
};
|
|
|
|
v |= v >> 1;
|
|
v |= v >> 2;
|
|
v |= v >> 4;
|
|
v |= v >> 8;
|
|
v |= v >> 16;
|
|
v |= v >> 32;
|
|
|
|
return MultiplyDeBruijnBitPosition[(uint64_t)(v * 0x03f6eaf2cd271461) >> 58];
|
|
}
|
|
|
|
|
|
|
|
template<typename word_t = uint32_t, size_t r = 20, size_t b = 128, word_t P = 0xB7E15163, word_t Q = 0x9E3779B9>
|
|
class RC6 {
|
|
static constexpr size_t word_size = 8*sizeof(word_t);
|
|
static word_t r_l(const word_t& w, size_t v) {
|
|
return (w << v) | ( w >> (sizeof(w)-v));
|
|
}
|
|
|
|
static word_t r_r(const word_t& w, size_t v) {
|
|
return (w >> v) | ( w << (sizeof(w)-v));
|
|
}
|
|
|
|
class RC6_KeySched {
|
|
public:
|
|
static constexpr size_t c = (b+word_size-1)/word_size;
|
|
static constexpr size_t v_3 = std::max(c, 2*r+4);
|
|
static constexpr size_t v = v_3*3;
|
|
private:
|
|
std::array<word_t, 2*r+4> S;
|
|
public:
|
|
RC6_KeySched(std::array<word_t, c> L)
|
|
{
|
|
S[0] = P;
|
|
for(auto it = S.begin()+1; it < S.end(); ++it)
|
|
{
|
|
*it = *(it-1) + Q;
|
|
}
|
|
word_t A = 0;
|
|
word_t B = 0;
|
|
word_t i = 0;
|
|
word_t j = 0;
|
|
|
|
for(size_t s = 0; s < v; ++s)
|
|
{
|
|
i = s % (2*r+4);
|
|
j = s % c;
|
|
A = S[i] = r_l( S[i] + A + B, 3 );
|
|
B = L[j] = r_l( L[j] + A + B, (A + B)%(word_size));
|
|
}
|
|
}
|
|
|
|
const word_t& operator[](const size_t pos) {
|
|
return S[pos];
|
|
}
|
|
};
|
|
|
|
RC6_KeySched S;
|
|
|
|
public:
|
|
|
|
typedef std::array<word_t, RC6_KeySched::c> key_type;
|
|
typedef std::array<word_t, 4> block_type;
|
|
|
|
RC6(const key_type& key)
|
|
: S(key)
|
|
{}
|
|
|
|
void encrypt(block_type& plaintext) {
|
|
auto& A = plaintext[0];
|
|
auto& B = plaintext[1];
|
|
auto& C = plaintext[2];
|
|
auto& D = plaintext[3];
|
|
|
|
B += S[0];
|
|
D += S[1];
|
|
|
|
for(size_t i = 1; i <= r; ++i)
|
|
{
|
|
auto t = r_l( B * ( 2 * B + 1 ), 5);
|
|
auto u = r_l( D * ( 2 * D + 1 ), 5);
|
|
A = r_l((A ^ t), u % word_size) + S[ 2 * i ];
|
|
C = r_l((C ^ u), t % word_size) + S[ 2 * i + 1 ];
|
|
auto tmp = A; A = B; B = C; C = D; D = tmp;
|
|
}
|
|
|
|
A += S[2*r+2];
|
|
C += S[2*r+3];
|
|
}
|
|
|
|
};
|