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-rw-r--r--CryptoPP/rc6.cpp96
1 files changed, 96 insertions, 0 deletions
diff --git a/CryptoPP/rc6.cpp b/CryptoPP/rc6.cpp
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+++ b/CryptoPP/rc6.cpp
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+// 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 &params)
+{
+ 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