1 files changed, 105 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pubkey/xmss/xmss_index_registry.h b/comm/third_party/botan/src/lib/pubkey/xmss/xmss_index_registry.h
new file mode 100644
index 0000000000..91166db4ba
--- /dev/null
+++ b/comm/third_party/botan/src/lib/pubkey/xmss/xmss_index_registry.h
@@ -0,0 +1,105 @@
+/*
+ * XMSS Index Registry
+ * (C) 2016 Matthias Gierlings
+ *
+ * Botan is released under the Simplified BSD License (see license.txt)
+ **/
+
+#ifndef BOTAN_XMSS_INDEX_REGISTRY_H_
+#define BOTAN_XMSS_INDEX_REGISTRY_H_
+
+#include <string>
+
+#include <botan/secmem.h>
+#include <botan/internal/atomic.h>
+#include <botan/mutex.h>
+
+//BOTAN_FUTURE_INTERNAL_HEADER(xmss_index_registry.h)
+
+namespace Botan {
+
+/**
+ * A registry for XMSS private keys, keeps track of the leaf index for
+ * independend copies of the same key.
+ **/
+class XMSS_Index_Registry final
+   {
+   public:
+      XMSS_Index_Registry(const XMSS_Index_Registry&) = delete;
+      XMSS_Index_Registry& operator=(const XMSS_Index_Registry&) = delete;
+
+      /**
+       * Retrieves a handle to the process-wide unique XMSS index registry.
+       *
+       * @return Reference to unique XMSS index registry.
+       **/
+      static XMSS_Index_Registry& get_instance()
+         {
+         static XMSS_Index_Registry self;
+         return self;
+         }
+
+      /**
+       * Retrieves the last unused leaf index for the private key identified
+       * by private_seed and prf. The leaf index will be updated properly
+       * across independent copies of private_key.
+       *
+       * @param private_seed Part of the unique identifier for an
+       *                     XMSS_PrivateKey.
+       * @param prf Part of the unique identifier for an XMSS_PrivateKey.
+       *
+       * @return last unused leaf index for private_key.
+       **/
+      std::shared_ptr<Atomic<size_t>>
+                                   get(const secure_vector<uint8_t>& private_seed,
+                                       const secure_vector<uint8_t>& prf);
+
+   private:
+      XMSS_Index_Registry() = default;
+
+      static const std::string m_index_hash_function;
+
+      /**
+       * Creates a unique 64-bit id for an XMSS_Private key, by interpreting
+       * the first 64-bit of HASH(PRIVATE_SEED || PRF) as 64 bit integer
+       * value.
+       *
+       * @return unique integral identifier for an XMSS private key.
+       **/
+      uint64_t make_key_id(const secure_vector<uint8_t>& private_seed,
+                           const secure_vector<uint8_t>& prf) const;
+
+      /**
+       * Retrieves the index position of a key within the registry or
+       * max(size_t) if key has not been found.
+       *
+       * @param id unique id of the XMSS private key (see make_key_id()).
+       *
+       * @return index position of key or max(size_t) if key not found.
+       **/
+      size_t get(uint64_t id) const;
+
+      /**
+       * If XMSS_PrivateKey identified by id is already registered, the
+       * position of the according registry entry is returned. If last_unused
+       * is bigger than the last unused index stored for the key identified by
+       * id the unused leaf index for this key is set to last_unused. If no key
+       * matching id is registed yet, an entry of id is added, with the last
+       * unused leaf index initialized to the value of last_unused.
+       *
+       * @last_unused Initial value for the last unused leaf index of the
+       *              registered key.
+       *
+       * @return positon of leaf index registry entry for key identified
+       *         by id.
+       **/
+      size_t add(uint64_t id, size_t last_unused = 0);
+
+      std::vector<uint64_t> m_key_ids;
+      std::vector<std::shared_ptr<Atomic<size_t>>> m_leaf_indices;
+      mutex_type m_mutex;
+   };
+
+}
+
+#endif