1 files changed, 135 insertions, 0 deletions
diff --git a/src/lib/block/rc5/rc5.cpp b/src/lib/block/rc5/rc5.cpp
new file mode 100644
index 000000000..f370e6cfb
--- /dev/null
+++ b/src/lib/block/rc5/rc5.cpp
@@ -0,0 +1,135 @@
+/*
+* RC5
+* (C) 1999-2007 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/rc5.h>
+#include <botan/loadstor.h>
+#include <botan/rotate.h>
+#include <botan/parsing.h>
+#include <algorithm>
+
+namespace Botan {
+
+/*
+* RC5 Encryption
+*/
+void RC5::encrypt_n(const byte in[], byte out[], size_t blocks) const
+   {
+   for(size_t i = 0; i != blocks; ++i)
+      {
+      u32bit A = load_le<u32bit>(in, 0);
+      u32bit B = load_le<u32bit>(in, 1);
+
+      A += S[0]; B += S[1];
+      for(size_t j = 0; j != rounds; j += 4)
+         {
+         A = rotate_left(A ^ B, B % 32) + S[2*j+2];
+         B = rotate_left(B ^ A, A % 32) + S[2*j+3];
+
+         A = rotate_left(A ^ B, B % 32) + S[2*j+4];
+         B = rotate_left(B ^ A, A % 32) + S[2*j+5];
+
+         A = rotate_left(A ^ B, B % 32) + S[2*j+6];
+         B = rotate_left(B ^ A, A % 32) + S[2*j+7];
+
+         A = rotate_left(A ^ B, B % 32) + S[2*j+8];
+         B = rotate_left(B ^ A, A % 32) + S[2*j+9];
+         }
+
+      store_le(out, A, B);
+
+      in += BLOCK_SIZE;
+      out += BLOCK_SIZE;
+      }
+   }
+
+/*
+* RC5 Decryption
+*/
+void RC5::decrypt_n(const byte in[], byte out[], size_t blocks) const
+   {
+   for(size_t i = 0; i != blocks; ++i)
+      {
+      u32bit A = load_le<u32bit>(in, 0);
+      u32bit B = load_le<u32bit>(in, 1);
+
+      for(size_t j = rounds; j != 0; j -= 4)
+         {
+         B = rotate_right(B - S[2*j+1], A % 32) ^ A;
+         A = rotate_right(A - S[2*j  ], B % 32) ^ B;
+
+         B = rotate_right(B - S[2*j-1], A % 32) ^ A;
+         A = rotate_right(A - S[2*j-2], B % 32) ^ B;
+
+         B = rotate_right(B - S[2*j-3], A % 32) ^ A;
+         A = rotate_right(A - S[2*j-4], B % 32) ^ B;
+
+         B = rotate_right(B - S[2*j-5], A % 32) ^ A;
+         A = rotate_right(A - S[2*j-6], B % 32) ^ B;
+         }
+      B -= S[1]; A -= S[0];
+
+      store_le(out, A, B);
+
+      in += BLOCK_SIZE;
+      out += BLOCK_SIZE;
+      }
+   }
+
+/*
+* RC5 Key Schedule
+*/
+void RC5::key_schedule(const byte key[], size_t length)
+   {
+   S.resize(2*rounds + 2);
+
+   const size_t WORD_KEYLENGTH = (((length - 1) / 4) + 1);
+   const size_t MIX_ROUNDS     = 3 * std::max(WORD_KEYLENGTH, S.size());
+
+   S[0] = 0xB7E15163;
+   for(size_t i = 1; i != S.size(); ++i)
+      S[i] = S[i-1] + 0x9E3779B9;
+
+   secure_vector<u32bit> K(8);
+
+   for(s32bit i = length-1; i >= 0; --i)
+      K[i/4] = (K[i/4] << 8) + key[i];
+
+   u32bit A = 0, B = 0;
+
+   for(size_t i = 0; i != MIX_ROUNDS; ++i)
+      {
+      A = rotate_left(S[i % S.size()] + A + B, 3);
+      B = rotate_left(K[i % WORD_KEYLENGTH] + A + B, (A + B) % 32);
+      S[i % S.size()] = A;
+      K[i % WORD_KEYLENGTH] = B;
+      }
+   }
+
+void RC5::clear()
+   {
+   zap(S);
+   }
+
+/*
+* Return the name of this type
+*/
+std::string RC5::name() const
+   {
+   return "RC5(" + std::to_string(rounds) + ")";
+   }
+
+/*
+* RC5 Constructor
+*/
+RC5::RC5(size_t r) : rounds(r)
+   {
+   if(rounds < 8 || rounds > 32 || (rounds % 4 != 0))
+      throw Invalid_Argument("RC5: Invalid number of rounds " +
+                             std::to_string(rounds));
+   }
+
+}