wallet: encrypt the cache file

It contains private data, such as a record of transactions.
The key is derived from the view and spend secret keys.

The encryption currently is one shot, so may require a lot of
memory for large wallet caches.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index ffe9ad0e5..cb816f83b 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -133,6 +133,17 @@ namespace tools
       END_SERIALIZE()
     };
 
+    struct cache_file_data
+    {
+      crypto::chacha8_iv iv;
+      std::string cache_data;
+
+      BEGIN_SERIALIZE_OBJECT()
+        FIELD(iv)
+        FIELD(cache_data)
+      END_SERIALIZE()
+    };
+
     /*!
      * \brief Generates a wallet or restores one.
      * \param  wallet_        Name of wallet file
@@ -307,6 +318,7 @@ namespace tools
     void add_unconfirmed_tx(const cryptonote::transaction& tx, uint64_t change_amount);
     void generate_genesis(cryptonote::block& b);
     void check_genesis(const crypto::hash& genesis_hash) const; //throws
+    bool generate_chacha8_key_from_secret_keys(crypto::chacha8_key &key) const;
 
     cryptonote::account_base m_account;
     std::string m_daemon_address;