1 files changed, 98 insertions, 0 deletions
diff --git a/lib/block/cascade/cascade.cpp b/lib/block/cascade/cascade.cpp
new file mode 100644
index 000000000..f1b1a8f2c
--- /dev/null
+++ b/lib/block/cascade/cascade.cpp
@@ -0,0 +1,98 @@
+/*
+* Block Cipher Cascade
+* (C) 2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/cascade.h>
+
+namespace Botan {
+
+void Cascade_Cipher::encrypt_n(const byte in[], byte out[],
+                               size_t blocks) const
+   {
+   size_t c1_blocks = blocks * (block_size() / cipher1->block_size());
+   size_t c2_blocks = blocks * (block_size() / cipher2->block_size());
+
+   cipher1->encrypt_n(in, out, c1_blocks);
+   cipher2->encrypt_n(out, out, c2_blocks);
+   }
+
+void Cascade_Cipher::decrypt_n(const byte in[], byte out[],
+                               size_t blocks) const
+   {
+   size_t c1_blocks = blocks * (block_size() / cipher1->block_size());
+   size_t c2_blocks = blocks * (block_size() / cipher2->block_size());
+
+   cipher2->decrypt_n(in, out, c2_blocks);
+   cipher1->decrypt_n(out, out, c1_blocks);
+   }
+
+void Cascade_Cipher::key_schedule(const byte key[], size_t)
+   {
+   const byte* key2 = key + cipher1->maximum_keylength();
+
+   cipher1->set_key(key , cipher1->maximum_keylength());
+   cipher2->set_key(key2, cipher2->maximum_keylength());
+   }
+
+void Cascade_Cipher::clear()
+   {
+   cipher1->clear();
+   cipher2->clear();
+   }
+
+std::string Cascade_Cipher::name() const
+   {
+   return "Cascade(" + cipher1->name() + "," + cipher2->name() + ")";
+   }
+
+BlockCipher* Cascade_Cipher::clone() const
+   {
+   return new Cascade_Cipher(cipher1->clone(),
+                             cipher2->clone());
+   }
+
+namespace {
+
+size_t euclids_algorithm(size_t a, size_t b)
+   {
+   while(b != 0) // gcd
+      {
+      size_t t = b;
+      b = a % b;
+      a = t;
+      }
+
+   return a;
+   }
+
+size_t block_size_for_cascade(size_t bs, size_t bs2)
+   {
+   if(bs == bs2)
+      return bs;
+
+   size_t gcd = euclids_algorithm(bs, bs2);
+
+   return (bs * bs2) / gcd;
+   }
+
+}
+
+Cascade_Cipher::Cascade_Cipher(BlockCipher* c1, BlockCipher* c2) :
+   cipher1(c1), cipher2(c2)
+   {
+   block = block_size_for_cascade(c1->block_size(), c2->block_size());
+
+   if(block_size() % c1->block_size() || block_size() % c2->block_size())
+      throw Internal_Error("Failure in " + name() + " constructor");
+   }
+
+Cascade_Cipher::~Cascade_Cipher()
+   {
+   delete cipher1;
+   delete cipher2;
+   }
+
+}