diff --git a/CMakeLists.txt b/CMakeLists.txt
index 094d906..7ae33cc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,6 +6,7 @@
 
 option(ENABLE_PROGRAMS "Build mbed TLS programs." ON)
 
+option(UNSAFE_BUILD "Allow unsafe builds. These builds ARE NOT SECURE." OFF)
 
 # the test suites currently have compile errors with MSVC
 if(MSVC)
@@ -14,6 +15,35 @@
     option(ENABLE_TESTING "Build mbed TLS tests." ON)
 endif()
 
+find_package(Perl)
+if(PERL_FOUND)
+
+    # If NULL Entropy is configured, display an appropriate warning
+    execute_process(COMMAND ${PERL_EXECUTABLE} scripts/config.pl get MBEDTLS_TEST_NULL_ENTROPY
+                        RESULT_VARIABLE result)
+    if(${result} EQUAL 0)
+        message(WARNING "\
+            *******************************************************
+            ****  WARNING!  MBEDTLS_TEST_NULL_ENTROPY defined!
+            ****  THIS BUILD HAS NO DEFINED ENTROPY SOURCES
+            ****  AND IS *NOT* SUITABLE FOR PRODUCTION USE
+            *******************************************************")
+        if(NOT UNSAFE_BUILD)
+            message(FATAL_ERROR "\
+\n\
+Warning! You have enabled MBEDTLS_TEST_NULL_ENTROPY. \
+This option is not safe for production use and negates all security \
+It is intended for development use only. \
+\n\
+To confirm you want to build with this option, re-run cmake with the \
+option: \n\
+  cmake -DUNSAFE_BUILD=ON ")
+
+            return()
+        endif()
+    endif()
+endif()
+
 set(CMAKE_BUILD_TYPE ${CMAKE_BUILD_TYPE}
     CACHE STRING "Choose the type of build: None Debug Release Coverage ASan ASanDbg MemSan MemSanDbg Check CheckFull"
     FORCE)