Link with libsodium and replace a CSPRNG.

configure.ac

@@ -717,7 +717,7 @@ CPPFLAGS="-I$LIBSNARK_INCDIR $CPPFLAGS"
 AC_CHECK_HEADER([libsnark/gadgetlib1/gadget.hpp],,AC_MSG_ERROR(libsnark headers missing))
 AC_CHECK_LIB([snark],[main],LIBSNARK_LIBS=-lsnark, [AC_MSG_ERROR(libsnark missing)], [-lgmpxx])
 
-LIBZEROCASH_LIBS="-lsnark -lcryptopp -lgmp -lgmpxx -lboost_system-mt -lcrypto"
+LIBZEROCASH_LIBS="-lsnark -lcryptopp -lgmp -lgmpxx -lboost_system-mt -lcrypto -lsodium"
 
 AC_CHECK_LIB([crypto],[RAND_egd],[],[
   AC_ARG_WITH([libressl],

src/zerocash/utils/util.cpp

@@ -9,6 +9,8 @@
 #include <iomanip>
 #include <algorithm>
 
+#include <sodium.h>
+
 #include "util.h"
 
 namespace libzerocash {
@@ -82,9 +84,7 @@ void printBytesVectorAsHex(const std::string str, const std::vector<unsigned cha
 }
 
 void getRandBytes(unsigned char* bytes, int num) {
-    int ret = RAND_bytes(bytes, num);
-    if(ret != 1)
-        std::cout << "rand_bytes error!" << ERR_get_error() << std::endl;
+    randombytes_buf(bytes, num);
 }
 
 void convertBytesToVector(const unsigned char* bytes, std::vector<bool>& v) {