5 files changed, 41 insertions, 2 deletions
diff --git a/src/crypto/crypto.cpp b/src/crypto/crypto.cpp
index d4b2a22bc..0ec992de9 100644
--- a/src/crypto/crypto.cpp
+++ b/src/crypto/crypto.cpp
@@ -88,13 +88,24 @@ namespace crypto {
     return &reinterpret_cast<const unsigned char &>(scalar);
   }
 
-  void generate_random_bytes_thread_safe(size_t N, uint8_t *bytes)
+  boost::mutex &get_random_lock()
   {
     static boost::mutex random_lock;
-    boost::lock_guard<boost::mutex> lock(random_lock);
+    return random_lock;
+  }
+
+  void generate_random_bytes_thread_safe(size_t N, uint8_t *bytes)
+  {
+    boost::lock_guard<boost::mutex> lock(get_random_lock());
     generate_random_bytes_not_thread_safe(N, bytes);
   }
 
+  void add_extra_entropy_thread_safe(const void *ptr, size_t bytes)
+  {
+    boost::lock_guard<boost::mutex> lock(get_random_lock());
+    add_extra_entropy_not_thread_safe(ptr, bytes);
+  }
+
   static inline bool less32(const unsigned char *k0, const unsigned char *k1)
   {
     for (int n = 31; n >= 0; --n)
diff --git a/src/crypto/crypto.h b/src/crypto/crypto.h
index bac456f60..8ce321f71 100644
--- a/src/crypto/crypto.h
+++ b/src/crypto/crypto.h
@@ -147,6 +147,7 @@ namespace crypto {
   };
 
   void generate_random_bytes_thread_safe(size_t N, uint8_t *bytes);
+  void add_extra_entropy_thread_safe(const void *ptr, size_t bytes);
 
   /* Generate N random bytes
    */
diff --git a/src/crypto/random.c b/src/crypto/random.c
index 74b202661..766b5f558 100644
--- a/src/crypto/random.c
+++ b/src/crypto/random.c
@@ -146,3 +146,18 @@ void generate_random_bytes_not_thread_safe(size_t n, void *result) {
     }
   }
 }
+
+void add_extra_entropy_not_thread_safe(const void *ptr, size_t bytes)
+{
+  size_t i;
+
+  while (bytes > 0)
+  {
+    hash_permutation(&state);
+    const size_t round_bytes = bytes > HASH_DATA_AREA ? HASH_DATA_AREA : bytes;
+    for (i = 0; i < round_bytes; ++i)
+      state.b[i] ^= ((const uint8_t*)ptr)[i];
+    bytes -= round_bytes;
+    ptr = cpadd(ptr, round_bytes);
+  }
+}
diff --git a/src/crypto/random.h b/src/crypto/random.h
index ccb9f4853..21a66d776 100644
--- a/src/crypto/random.h
+++ b/src/crypto/random.h
@@ -33,3 +33,4 @@
 #include <stddef.h>
 
 void generate_random_bytes_not_thread_safe(size_t n, void *result);
+void add_extra_entropy_not_thread_safe(const void *ptr, size_t bytes);
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index 88ef53377..155f44129 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -278,6 +278,7 @@ struct options {
   const command_line::arg_descriptor<std::string> tx_notify = { "tx-notify" , "Run a program for each new incoming transaction, '%s' will be replaced by the transaction hash" , "" };
   const command_line::arg_descriptor<bool> no_dns = {"no-dns", tools::wallet2::tr("Do not use DNS"), false};
   const command_line::arg_descriptor<bool> offline = {"offline", tools::wallet2::tr("Do not connect to a daemon, nor use DNS"), false};
+  const command_line::arg_descriptor<std::string> extra_entropy = {"extra-entropy", tools::wallet2::tr("File containing extra entropy to initialize the PRNG (any data, aim for 256 bits of entropy to be useful, wihch typically means more than 256 bits of data)")};
 };
 
 void do_prepare_file_names(const std::string& file_path, std::string& keys_file, std::string& wallet_file, std::string &mms_file)
@@ -479,6 +480,15 @@ std::unique_ptr<tools::wallet2> make_basic(const boost::program_options::variabl
   if (command_line::get_arg(vm, opts.offline))
     wallet->set_offline();
 
+  const std::string extra_entropy = command_line::get_arg(vm, opts.extra_entropy);
+  if (!extra_entropy.empty())
+  {
+    std::string data;
+    THROW_WALLET_EXCEPTION_IF(!epee::file_io_utils::load_file_to_string(extra_entropy, data),
+        tools::error::wallet_internal_error, "Failed to load extra entropy from " + extra_entropy);
+    add_extra_entropy_thread_safe(data.data(), data.size());
+  }
+
   try
   {
     if (!command_line::is_arg_defaulted(vm, opts.tx_notify))
@@ -1204,6 +1214,7 @@ void wallet2::init_options(boost::program_options::options_description& desc_par
   command_line::add_arg(desc_params, opts.tx_notify);
   command_line::add_arg(desc_params, opts.no_dns);
   command_line::add_arg(desc_params, opts.offline);
+  command_line::add_arg(desc_params, opts.extra_entropy);
 }
 
 std::pair<std::unique_ptr<wallet2>, tools::password_container> wallet2::make_from_json(const boost::program_options::variables_map& vm, bool unattended, const std::string& json_file, const std::function<boost::optional<tools::password_container>(const char *, bool)> &password_prompter)