mirror of
https://github.com/shadps4-emu/ext-cryptopp.git
synced 2024-11-30 21:30:31 +00:00
97 lines
2.2 KiB
C++
97 lines
2.2 KiB
C++
// rc6.cpp - written and placed in the public domain by Sean Woods
|
|
// based on Wei Dai's RC5 code.
|
|
|
|
#include "pch.h"
|
|
#include "rc6.h"
|
|
#include "misc.h"
|
|
|
|
NAMESPACE_BEGIN(CryptoPP)
|
|
|
|
void RC6::Base::UncheckedSetKey(const byte *k, unsigned int keylen, const NameValuePairs ¶ms)
|
|
{
|
|
AssertValidKeyLength(keylen);
|
|
|
|
r = GetRoundsAndThrowIfInvalid(params, this);
|
|
sTable.New(2*(r+2));
|
|
|
|
static const RC6_WORD MAGIC_P = 0xb7e15163L; // magic constant P for wordsize
|
|
static const RC6_WORD MAGIC_Q = 0x9e3779b9L; // magic constant Q for wordsize
|
|
static const int U=sizeof(RC6_WORD);
|
|
|
|
const unsigned int c = STDMAX((keylen+U-1)/U, 1U); // RC6 paper says c=1 if keylen==0
|
|
SecBlock<RC6_WORD> l(c);
|
|
|
|
GetUserKey(LITTLE_ENDIAN_ORDER, l.begin(), c, k, keylen);
|
|
|
|
sTable[0] = MAGIC_P;
|
|
for (unsigned j=1; j<sTable.size();j++)
|
|
sTable[j] = sTable[j-1] + MAGIC_Q;
|
|
|
|
RC6_WORD a=0, b=0;
|
|
const unsigned n = 3*STDMAX((unsigned int)sTable.size(), c);
|
|
|
|
for (unsigned h=0; h < n; h++)
|
|
{
|
|
a = sTable[h % sTable.size()] = rotlFixed((sTable[h % sTable.size()] + a + b), 3);
|
|
b = l[h % c] = rotlMod((l[h % c] + a + b), (a+b));
|
|
}
|
|
}
|
|
|
|
typedef BlockGetAndPut<RC6::RC6_WORD, LittleEndian> Block;
|
|
|
|
void RC6::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
|
|
{
|
|
const RC6_WORD *sptr = sTable;
|
|
RC6_WORD a, b, c, d, t, u;
|
|
|
|
Block::Get(inBlock)(a)(b)(c)(d);
|
|
b += sptr[0];
|
|
d += sptr[1];
|
|
sptr += 2;
|
|
|
|
for(unsigned i=0; i<r; i++)
|
|
{
|
|
t = rotlFixed(b*(2*b+1), 5);
|
|
u = rotlFixed(d*(2*d+1), 5);
|
|
a = rotlMod(a^t,u) + sptr[0];
|
|
c = rotlMod(c^u,t) + sptr[1];
|
|
t = a; a = b; b = c; c = d; d = t;
|
|
sptr += 2;
|
|
}
|
|
|
|
a += sptr[0];
|
|
c += sptr[1];
|
|
|
|
Block::Put(xorBlock, outBlock)(a)(b)(c)(d);
|
|
}
|
|
|
|
void RC6::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
|
|
{
|
|
const RC6_WORD *sptr = sTable.end();
|
|
RC6_WORD a, b, c, d, t, u;
|
|
|
|
Block::Get(inBlock)(a)(b)(c)(d);
|
|
|
|
sptr -= 2;
|
|
c -= sptr[1];
|
|
a -= sptr[0];
|
|
|
|
for (unsigned i=0; i < r; i++)
|
|
{
|
|
sptr -= 2;
|
|
t = a; a = d; d = c; c = b; b = t;
|
|
u = rotlFixed(d*(2*d+1), 5);
|
|
t = rotlFixed(b*(2*b+1), 5);
|
|
c = rotrMod(c-sptr[1], t) ^ u;
|
|
a = rotrMod(a-sptr[0], u) ^ t;
|
|
}
|
|
|
|
sptr -= 2;
|
|
d -= sTable[1];
|
|
b -= sTable[0];
|
|
|
|
Block::Put(xorBlock, outBlock)(a)(b)(c)(d);
|
|
}
|
|
|
|
NAMESPACE_END
|