Initial checkin1.5.6

1 files changed, 104 insertions, 0 deletions

diff --git a/src/rc5.cpp b/src/rc5.cpp
new file mode 100644
index 000000000..f475a26ad
--- /dev/null
+++ b/src/rc5.cpp
@@ -0,0 +1,104 @@
+/*************************************************
+* RC5 Source File                                *
+* (C) 1999-2006 The Botan Project                *
+*************************************************/
+
+#include <botan/rc5.h>
+#include <botan/bit_ops.h>
+#include <botan/parsing.h>
+#include <algorithm>
+
+namespace Botan {
+
+/*************************************************
+* RC5 Encryption                                 *
+*************************************************/
+void RC5::enc(const byte in[], byte out[]) const
+   {
+   u32bit A = make_u32bit(in[3], in[2], in[1], in[0]),
+          B = make_u32bit(in[7], in[6], in[5], in[4]);
+   A += S[0]; B += S[1];
+   for(u32bit 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];
+      }
+   out[0] = get_byte(3, A); out[1] = get_byte(2, A);
+   out[2] = get_byte(1, A); out[3] = get_byte(0, A);
+   out[4] = get_byte(3, B); out[5] = get_byte(2, B);
+   out[6] = get_byte(1, B); out[7] = get_byte(0, B);
+   }
+
+/*************************************************
+* RC5 Decryption                                 *
+*************************************************/
+void RC5::dec(const byte in[], byte out[]) const
+   {
+   u32bit A = make_u32bit(in[3], in[2], in[1], in[0]),
+          B = make_u32bit(in[7], in[6], in[5], in[4]);
+   for(u32bit 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];
+   out[0] = get_byte(3, A); out[1] = get_byte(2, A);
+   out[2] = get_byte(1, A); out[3] = get_byte(0, A);
+   out[4] = get_byte(3, B); out[5] = get_byte(2, B);
+   out[6] = get_byte(1, B); out[7] = get_byte(0, B);
+   }
+
+/*************************************************
+* RC5 Key Schedule                               *
+*************************************************/
+void RC5::key(const byte key[], u32bit length)
+   {
+   const u32bit WORD_KEYLENGTH = (((length - 1) / 4) + 1),
+                MIX_ROUNDS     = 3*std::max(WORD_KEYLENGTH, S.size());
+   S[0] = 0xB7E15163;
+   for(u32bit j = 1; j != S.size(); ++j)
+      S[j] = S[j-1] + 0x9E3779B9;
+
+   SecureBuffer<u32bit, 8> K;
+   for(s32bit j = length-1; j >= 0; --j)
+      K[j/4] = (K[j/4] << 8) + key[j];
+   for(u32bit j = 0, A = 0, B = 0; j != MIX_ROUNDS; ++j)
+      {
+      A = rotate_left(S[j % S.size()] + A + B, 3);
+      B = rotate_left(K[j % WORD_KEYLENGTH] + A + B, (A + B) % 32);
+      S[j % S.size()] = A;
+      K[j % WORD_KEYLENGTH] = B;
+      }
+   }
+
+/*************************************************
+* Return the name of this type                   *
+*************************************************/
+std::string RC5::name() const
+   {
+   return "RC5(" + to_string(ROUNDS) + ")";
+   }
+
+/*************************************************
+* RC5 Constructor                                *
+*************************************************/
+RC5::RC5(u32bit r) : BlockCipher(8, 1, 32), ROUNDS(r)
+   {
+   if(ROUNDS < 8 || ROUNDS > 32 || (ROUNDS % 4 != 0))
+      throw Invalid_Argument(name() + ": Invalid number of rounds");
+   S.create(2*ROUNDS + 2);
+   }
+
+}