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Diffstat (limited to '')
| -rw-r--r-- | CryptoPP/rc5.cpp | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/CryptoPP/rc5.cpp b/CryptoPP/rc5.cpp new file mode 100644 index 000000000..2b730def7 --- /dev/null +++ b/CryptoPP/rc5.cpp @@ -0,0 +1,79 @@ +// 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 ¶ms) +{ + 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 |