1 files changed, 96 insertions, 0 deletions
diff --git a/src/lib/pubkey/xmss/xmss_signature.cpp b/src/lib/pubkey/xmss/xmss_signature.cpp
new file mode 100644
index 000000000..f31dcd8bb
--- /dev/null
+++ b/src/lib/pubkey/xmss/xmss_signature.cpp
@@ -0,0 +1,96 @@
+/**
+ * XMSS Signature
+ * (C) 2016 Matthias Gierlings
+ *
+ * Botan is released under the Simplified BSD License (see license.txt)
+ **/
+
+#include <botan/internal/xmss_signature.h>
+
+namespace Botan {
+
+XMSS_Signature::XMSS_Signature(XMSS_Parameters::xmss_algorithm_t oid,
+                               const secure_vector<byte>& raw_sig)
+   : m_leaf_idx(0), m_randomness(0, 0x00), m_tree_sig()
+   {
+   BOTAN_ASSERT(sizeof(size_t) >= ceil(static_cast<float>(
+                   (XMSS_Parameters(oid)).tree_height()) / 8.f),
+                   "System type \"size_t\" not big enough to support"
+                   " leaf index.");
+
+   XMSS_Parameters xmss_params(oid);
+   uint64_t leaf_idx = 0;
+   for(size_t i = 0; i < 8; i++)
+      leaf_idx = ((leaf_idx << 8) | raw_sig[i]);
+
+   if(leaf_idx >= (1ull << (xmss_params.tree_height() - 1)))
+      {
+      throw Integrity_Failure("XMSS signature leaf index out of "
+                              "bounds.");
+      }
+   m_leaf_idx = static_cast<size_t>(leaf_idx);
+
+   auto begin = raw_sig.begin() + sizeof(uint64_t);
+   auto end = begin + xmss_params.element_size();
+   std::copy(begin, end, std::back_inserter(m_randomness));
+
+   for(size_t i = 0; i < xmss_params.len(); i++)
+      {
+      begin = end;
+      end = begin + xmss_params.element_size();
+      m_tree_sig.ots_signature().push_back(secure_vector<byte>(0));
+      m_tree_sig.ots_signature().back().reserve(
+         xmss_params.element_size());
+      std::copy(begin,
+                end,
+                std::back_inserter(m_tree_sig.ots_signature().back()));
+      }
+
+   for(size_t i = 0; i < xmss_params.tree_height(); i++)
+      {
+      begin = end;
+      end = begin + xmss_params.element_size();
+      m_tree_sig.authentication_path().push_back(secure_vector<byte>(0));
+      m_tree_sig.authentication_path().back().reserve(
+         xmss_params.element_size());
+      std::copy(begin,
+                end,
+                std::back_inserter(m_tree_sig.authentication_path().back()));
+      }
+   }
+
+secure_vector<byte> XMSS_Signature::bytes() const
+   {
+   secure_vector<byte> result
+      {
+      static_cast<byte>(static_cast<uint64_t>(m_leaf_idx) >> 56U),
+      static_cast<byte>(static_cast<uint64_t>(m_leaf_idx) >> 48U),
+      static_cast<byte>(static_cast<uint64_t>(m_leaf_idx) >> 40U),
+      static_cast<byte>(static_cast<uint64_t>(m_leaf_idx) >> 32U),
+      static_cast<byte>(static_cast<uint64_t>(m_leaf_idx) >> 24U),
+      static_cast<byte>(static_cast<uint64_t>(m_leaf_idx) >> 16U),
+      static_cast<byte>(static_cast<uint64_t>(m_leaf_idx) >>  8U),
+      static_cast<byte>(static_cast<uint64_t>(m_leaf_idx)       )
+      };
+
+   std::copy(m_randomness.begin(),
+             m_randomness.end(),
+             std::back_inserter(result));
+
+   for(const auto& sig : tree().ots_signature())
+      {
+      std::copy(sig.begin(),
+                sig.end(),
+                std::back_inserter(result));
+      }
+
+   for(const auto& auth : tree().authentication_path())
+      {
+      std::copy(auth.begin(),
+                auth.end(),
+                std::back_inserter(result));
+      }
+   return result;
+   }
+
+}