wallet: add --extra-entropy command line flag

It lets the user add custom entropy to the PRNG.
It does this by hashing the new data and xoring the resulting
hash with the PRNG state.

1 files changed, 13 insertions, 2 deletions

diff --git a/src/crypto/crypto.cpp b/src/crypto/crypto.cpp
index 3f06c4f3f..6d3c4ed35 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)