diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index d31555df7c..407cd571ae 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -130,6 +130,17 @@
 #error "MBEDTLS_ENTROPY_FORCE_SHA256 defined, but not all prerequisites"
 #endif
 
+#if defined(MBEDTLS_TEST_WO_ENTROPY)
+#warning "MBEDTLS_TEST_WO_ENTROPY defined, this build provides no security!"
+#if !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES)
+#error "MBEDTLS_TEST_WO_ENTROPY defined, but not all prerequisites"
+#endif
+#if defined(MBEDTLS_ENTROPY_NV_SEED) || defined(MBEDTLS_ENTROPY_HARDWARE_ALT) || \
+    defined(MBEDTLS_HAVEGE_C)
+#error "MBEDTLS_TEST_WO_ENTROPY defined, but entropy sources too"
+#endif
+#endif
+
 #if defined(MBEDTLS_GCM_C) && (                                        \
         !defined(MBEDTLS_AES_C) && !defined(MBEDTLS_CAMELLIA_C) )
 #error "MBEDTLS_GCM_C defined, but not all prerequisites"
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 0efee04545..c42b88d74f 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -278,6 +278,29 @@
 //#define MBEDTLS_AES_ENCRYPT_ALT
 //#define MBEDTLS_AES_DECRYPT_ALT
 
+/**
+ * \def MBEDTLS_TEST_WO_ENTROPY
+ *
+ * Enable testing mbed TLS without access to any entropy. This enables testing
+ * the library before the platforms entropy sources are integrated (, see for
+ * example the MBEDTLS_ENTROPY_HARDWARE_ALT or the MBEDTLS_ENTROPY_NV_SEED
+ * switch).
+ *
+ * WARNING! This switch is extremely DANGEROUS, don't use it in production code
+ * under any circumstances. This switch nullifies any security provided by the
+ * library.
+ */
+//#define MBEDTLS_TEST_WO_ENTROPY
+
+
+/**
+ * \def MBEDTLS_ENTROPY_NV_SEED
+ *
+ * Strong software entropy source. It is not yet implemented,
+ * adding it because it is mutually exclusive with MBEDTLS_TEST_WO_ENTROPY.
+ */
+//#define MBEDTLS_ENTROPY_NV_SEED
+
 /**
  * \def MBEDTLS_ENTROPY_HARDWARE_ALT
  *
diff --git a/include/mbedtls/entropy_poll.h b/include/mbedtls/entropy_poll.h
index dc11911341..3fcfef269b 100644
--- a/include/mbedtls/entropy_poll.h
+++ b/include/mbedtls/entropy_poll.h
@@ -43,6 +43,14 @@ extern "C" {
 #define MBEDTLS_ENTROPY_MIN_HARDCLOCK     4     /**< Minimum for mbedtls_timing_hardclock()        */
 #define MBEDTLS_ENTROPY_MIN_HARDWARE     32     /**< Minimum for the hardware source */
 
+/**
+ * \brief           Entropy poll callback that provides 0 entropy.
+ */
+#if defined(MBEDTLS_TEST_WO_ENTROPY)
+    int mbedtls_zero_entropy_poll( void *data,
+                                unsigned char *output, size_t len, size_t *olen );
+#endif
+
 #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
 /**
  * \brief           Platform-specific entropy poll callback
diff --git a/library/entropy.c b/library/entropy.c
index cdbd35c34e..381f730946 100644
--- a/library/entropy.c
+++ b/library/entropy.c
@@ -73,6 +73,11 @@ void mbedtls_entropy_init( mbedtls_entropy_context *ctx )
     mbedtls_havege_init( &ctx->havege_data );
 #endif
 
+#if defined(MBEDTLS_TEST_WO_ENTROPY)
+    mbedtls_entropy_add_source( ctx, mbedtls_zero_entropy_poll, NULL,
+                                1, MBEDTLS_ENTROPY_SOURCE_STRONG );
+#endif
+
 #if !defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES)
 #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
     mbedtls_entropy_add_source( ctx, mbedtls_platform_entropy_poll, NULL,
diff --git a/library/entropy_poll.c b/library/entropy_poll.c
index e2f45c78a5..79efb87e9d 100644
--- a/library/entropy_poll.c
+++ b/library/entropy_poll.c
@@ -188,6 +188,22 @@ int mbedtls_platform_entropy_poll( void *data,
 #endif /* _WIN32 && !EFIX64 && !EFI32 */
 #endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */
 
+#if defined(MBEDTLS_TEST_WO_ENTROPY)
+int mbedtls_zero_entropy_poll( void *data,
+                    unsigned char *output, size_t len, size_t *olen )
+{
+    ((void) data);
+    *olen = 0;
+
+    if( len < sizeof(unsigned char) )
+        return( 0 );
+
+    *olen = sizeof(unsigned char);
+
+    return( 0 );
+}
+#endif
+
 #if defined(MBEDTLS_TIMING_C)
 int mbedtls_hardclock_poll( void *data,
                     unsigned char *output, size_t len, size_t *olen )
diff --git a/scripts/config.pl b/scripts/config.pl
index a6dcfe7d7f..ea7782108c 100755
--- a/scripts/config.pl
+++ b/scripts/config.pl
@@ -18,6 +18,7 @@
 #
 # Things that shouldn't be enabled with "full".
 #
+#   MBEDTLS_TEST_WO_ENTROPY
 #   MBEDTLS_DEPRECATED_REMOVED
 #   MBEDTLS_HAVE_SSE2
 #   MBEDTLS_PLATFORM_NO_STD_FUNCTIONS
@@ -69,6 +70,7 @@ Options
 EOU
 
 my @excluded = qw(
+MBEDTLS_TEST_WO_ENTROPY
 MBEDTLS_DEPRECATED_REMOVED
 MBEDTLS_HAVE_SSE2
 MBEDTLS_PLATFORM_NO_STD_FUNCTIONS