diff --git a/src/random.cpp b/src/random.cpp index 805d7d387..3b9df3eda 100644 --- a/src/random.cpp +++ b/src/random.cpp @@ -34,6 +34,8 @@ #include #endif +#include + #include #include @@ -201,6 +203,10 @@ void GetRandBytes(unsigned char* buf, int num) } } +static std::mutex cs_rng_state; +static unsigned char rng_state[32] = {0}; +static uint64_t rng_counter = 0; + void GetStrongRandBytes(unsigned char* out, int num) { assert(num <= 32); @@ -216,8 +222,17 @@ void GetStrongRandBytes(unsigned char* out, int num) GetOSRand(buf); hasher.Write(buf, 32); + // Combine with and update state + { + std::unique_lock lock(cs_rng_state); + hasher.Write(rng_state, sizeof(rng_state)); + hasher.Write((const unsigned char*)&rng_counter, sizeof(rng_counter)); + ++rng_counter; + hasher.Finalize(buf); + memcpy(rng_state, buf + 32, 32); + } + // Produce output - hasher.Finalize(buf); memcpy(out, buf, num); memory_cleanse(buf, 64); }