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-rw-r--r--CryptoPP/rc5.cpp79
1 files changed, 79 insertions, 0 deletions
diff --git a/CryptoPP/rc5.cpp b/CryptoPP/rc5.cpp
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+++ b/CryptoPP/rc5.cpp
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+// rc5.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+#include "rc5.h"
+#include "misc.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+void RC5::Base::UncheckedSetKey(const byte *k, unsigned int keylen, const NameValuePairs &params)
+{
+ AssertValidKeyLength(keylen);
+
+ r = GetRoundsAndThrowIfInvalid(params, this);
+ sTable.New(2*(r+1));
+
+ static const RC5_WORD MAGIC_P = 0xb7e15163L; // magic constant P for wordsize
+ static const RC5_WORD MAGIC_Q = 0x9e3779b9L; // magic constant Q for wordsize
+ static const int U=sizeof(RC5_WORD);
+
+ const unsigned int c = STDMAX((keylen+U-1)/U, 1U); // RC6 paper says c=1 if keylen==0
+ SecBlock<RC5_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;
+
+ RC5_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<RC5::RC5_WORD, LittleEndian> Block;
+
+void RC5::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
+{
+ const RC5_WORD *sptr = sTable;
+ RC5_WORD a, b;
+
+ Block::Get(inBlock)(a)(b);
+ a += sptr[0];
+ b += sptr[1];
+ sptr += 2;
+
+ for(unsigned i=0; i<r; i++)
+ {
+ a = rotlMod(a^b,b) + sptr[2*i+0];
+ b = rotlMod(a^b,a) + sptr[2*i+1];
+ }
+
+ Block::Put(xorBlock, outBlock)(a)(b);
+}
+
+void RC5::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
+{
+ const RC5_WORD *sptr = sTable.end();
+ RC5_WORD a, b;
+
+ Block::Get(inBlock)(a)(b);
+
+ for (unsigned i=0; i<r; i++)
+ {
+ sptr-=2;
+ b = rotrMod(b-sptr[1], a) ^ a;
+ a = rotrMod(a-sptr[0], b) ^ b;
+ }
+ b -= sTable[1];
+ a -= sTable[0];
+
+ Block::Put(xorBlock, outBlock)(a)(b);
+}
+
+NAMESPACE_END