1 files changed, 84 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pubkey/xmss/xmss_index_registry.cpp b/comm/third_party/botan/src/lib/pubkey/xmss/xmss_index_registry.cpp
new file mode 100644
index 0000000000..8709d8026f
--- /dev/null
+++ b/comm/third_party/botan/src/lib/pubkey/xmss/xmss_index_registry.cpp
@@ -0,0 +1,84 @@
+/*
+ * XMSS Index Registry
+ * A registry for XMSS private keys, keeps track of the leaf index for
+ * independend copies of the same key.
+ * (C) 2016 Matthias Gierlings
+ *
+ * Botan is released under the Simplified BSD License (see license.txt)
+ **/
+
+#include <botan/internal/xmss_index_registry.h>
+#include <botan/hash.h>
+#include <limits>
+
+namespace Botan {
+
+const std::string XMSS_Index_Registry::m_index_hash_function = "SHA-256";
+
+uint64_t XMSS_Index_Registry::make_key_id(
+   const secure_vector<uint8_t>& private_seed,
+   const secure_vector<uint8_t>& prf) const
+   {
+   std::unique_ptr<HashFunction> hash =
+      HashFunction::create(m_index_hash_function);
+   BOTAN_ASSERT(hash != nullptr, "XMSS_Index_Registry requires SHA-256");
+   hash->update(private_seed);
+   hash->update(prf);
+   secure_vector<uint8_t> result = hash->final();
+   uint64_t key_id = 0;
+   for(size_t i = 0; i < sizeof(key_id); i++)
+      {
+      key_id = ((key_id << 8) | result[i]);
+      }
+
+   return key_id;
+   }
+
+std::shared_ptr<Atomic<size_t>>
+XMSS_Index_Registry::get(const secure_vector<uint8_t>& private_seed,
+                         const secure_vector<uint8_t>& prf)
+   {
+   size_t pos = get(make_key_id(private_seed, prf));
+
+   if(pos < std::numeric_limits<size_t>::max())
+      {
+      return m_leaf_indices[pos];
+      }
+   else
+      {
+      return m_leaf_indices[add(make_key_id(private_seed, prf))];
+      }
+   }
+
+size_t XMSS_Index_Registry::get(uint64_t id) const
+   {
+   for(size_t i = 0; i < m_key_ids.size(); i++)
+      {
+      if(m_key_ids[i] == id)
+         {
+         return i;
+         }
+      }
+
+   return std::numeric_limits<size_t>::max();
+   }
+
+size_t XMSS_Index_Registry::add(uint64_t id, size_t last_unused)
+   {
+   lock_guard_type<mutex_type> lock(m_mutex);
+   size_t pos = get(id);
+   if(pos < m_key_ids.size())
+      {
+      if(last_unused > *(m_leaf_indices[pos]))
+         {
+         m_leaf_indices[pos] = std::make_shared<Atomic<size_t>>(last_unused);
+         }
+      return pos;
+      }
+
+   m_key_ids.push_back(id);
+   m_leaf_indices.push_back(std::make_shared<Atomic<size_t>>(last_unused));
+   return m_key_ids.size() - 1;
+   }
+
+}