1 files changed, 110 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/hash/comb4p/comb4p.cpp b/comm/third_party/botan/src/lib/hash/comb4p/comb4p.cpp
new file mode 100644
index 0000000000..419e00df54
--- /dev/null
+++ b/comm/third_party/botan/src/lib/hash/comb4p/comb4p.cpp
@@ -0,0 +1,110 @@
+/*
+* Comb4P hash combiner
+* (C) 2010 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/comb4p.h>
+#include <botan/exceptn.h>
+
+namespace Botan {
+
+namespace {
+
+void comb4p_round(secure_vector<uint8_t>& out,
+                  const secure_vector<uint8_t>& in,
+                  uint8_t round_no,
+                  HashFunction& h1,
+                  HashFunction& h2)
+   {
+   h1.update(round_no);
+   h2.update(round_no);
+
+   h1.update(in.data(), in.size());
+   h2.update(in.data(), in.size());
+
+   secure_vector<uint8_t> h_buf = h1.final();
+   xor_buf(out.data(), h_buf.data(), std::min(out.size(), h_buf.size()));
+
+   h_buf = h2.final();
+   xor_buf(out.data(), h_buf.data(), std::min(out.size(), h_buf.size()));
+   }
+
+}
+
+Comb4P::Comb4P(HashFunction* h1, HashFunction* h2) :
+   m_hash1(h1), m_hash2(h2)
+   {
+   if(m_hash1->name() == m_hash2->name())
+      throw Invalid_Argument("Comb4P: Must use two distinct hashes");
+
+   if(m_hash1->output_length() != m_hash2->output_length())
+      throw Invalid_Argument("Comb4P: Incompatible hashes " +
+                                  m_hash1->name() + " and " +
+                                  m_hash2->name());
+
+   clear();
+   }
+
+size_t Comb4P::hash_block_size() const
+   {
+   if(m_hash1->hash_block_size() == m_hash2->hash_block_size())
+      return m_hash1->hash_block_size();
+
+   /*
+   * Return LCM of the block sizes? This would probably be OK for
+   * HMAC, which is the main thing relying on knowing the block size.
+   */
+   return 0;
+   }
+
+void Comb4P::clear()
+   {
+   m_hash1->clear();
+   m_hash2->clear();
+
+   // Prep for processing next message, if any
+   m_hash1->update(0);
+   m_hash2->update(0);
+   }
+
+std::unique_ptr<HashFunction> Comb4P::copy_state() const
+   {
+   std::unique_ptr<Comb4P> copy(new Comb4P);
+   copy->m_hash1 = m_hash1->copy_state();
+   copy->m_hash2 = m_hash2->copy_state();
+   // work around GCC 4.8 bug
+   return std::unique_ptr<HashFunction>(copy.release());
+   }
+
+void Comb4P::add_data(const uint8_t input[], size_t length)
+   {
+   m_hash1->update(input, length);
+   m_hash2->update(input, length);
+   }
+
+void Comb4P::final_result(uint8_t out[])
+   {
+   secure_vector<uint8_t> h1 = m_hash1->final();
+   secure_vector<uint8_t> h2 = m_hash2->final();
+
+   // First round
+   xor_buf(h1.data(), h2.data(), std::min(h1.size(), h2.size()));
+
+   // Second round
+   comb4p_round(h2, h1, 1, *m_hash1, *m_hash2);
+
+   // Third round
+   comb4p_round(h1, h2, 2, *m_hash1, *m_hash2);
+
+   copy_mem(out            , h1.data(), h1.size());
+   copy_mem(out + h1.size(), h2.data(), h2.size());
+
+   // Prep for processing next message, if any
+   m_hash1->update(0);
+   m_hash2->update(0);
+   }
+
+}
+