1 files changed, 93 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/block/cascade/cascade.cpp b/comm/third_party/botan/src/lib/block/cascade/cascade.cpp
new file mode 100644
index 0000000000..6607fd5b27
--- /dev/null
+++ b/comm/third_party/botan/src/lib/block/cascade/cascade.cpp
@@ -0,0 +1,93 @@
+/*
+* Block Cipher Cascade
+* (C) 2010 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/cascade.h>
+
+namespace Botan {
+
+void Cascade_Cipher::encrypt_n(const uint8_t in[], uint8_t out[],
+                               size_t blocks) const
+   {
+   size_t c1_blocks = blocks * (block_size() / m_cipher1->block_size());
+   size_t c2_blocks = blocks * (block_size() / m_cipher2->block_size());
+
+   m_cipher1->encrypt_n(in, out, c1_blocks);
+   m_cipher2->encrypt_n(out, out, c2_blocks);
+   }
+
+void Cascade_Cipher::decrypt_n(const uint8_t in[], uint8_t out[],
+                               size_t blocks) const
+   {
+   size_t c1_blocks = blocks * (block_size() / m_cipher1->block_size());
+   size_t c2_blocks = blocks * (block_size() / m_cipher2->block_size());
+
+   m_cipher2->decrypt_n(in, out, c2_blocks);
+   m_cipher1->decrypt_n(out, out, c1_blocks);
+   }
+
+void Cascade_Cipher::key_schedule(const uint8_t key[], size_t)
+   {
+   const uint8_t* key2 = key + m_cipher1->maximum_keylength();
+
+   m_cipher1->set_key(key , m_cipher1->maximum_keylength());
+   m_cipher2->set_key(key2, m_cipher2->maximum_keylength());
+   }
+
+void Cascade_Cipher::clear()
+   {
+   m_cipher1->clear();
+   m_cipher2->clear();
+   }
+
+std::string Cascade_Cipher::name() const
+   {
+   return "Cascade(" + m_cipher1->name() + "," + m_cipher2->name() + ")";
+   }
+
+BlockCipher* Cascade_Cipher::clone() const
+   {
+   return new Cascade_Cipher(m_cipher1->clone(),
+                             m_cipher2->clone());
+   }
+
+namespace {
+
+size_t euclids_algorithm(size_t a, size_t b)
+   {
+   while(b != 0)
+      {
+      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;
+
+   const size_t gcd = euclids_algorithm(bs, bs2);
+
+   return (bs * bs2) / gcd;
+   }
+
+}
+
+Cascade_Cipher::Cascade_Cipher(BlockCipher* c1, BlockCipher* c2) :
+   m_cipher1(c1), m_cipher2(c2)
+   {
+   m_block = block_size_for_cascade(c1->block_size(), c2->block_size());
+
+   BOTAN_ASSERT(m_block % c1->block_size() == 0 &&
+                m_block % c2->block_size() == 0,
+                "Combined block size is a multiple of each ciphers block");
+   }
+
+}