diff --git a/programs/fuzz/common.c b/programs/fuzz/common.c
index 5e6c84c..ac39ee2 100644
--- a/programs/fuzz/common.c
+++ b/programs/fuzz/common.c
@@ -58,8 +58,13 @@
     int ret;
     size_t i;
 
+#if defined(MBEDTLS_CTR_DRBG_C)
     //use mbedtls_ctr_drbg_random to find bugs in it
     ret = mbedtls_ctr_drbg_random(p_rng, output, output_len);
+#else
+    (void) p_rng;
+    ret = 0;
+#endif
     for (i=0; i<output_len; i++) {
         //replace result with pseudo random
         output[i] = (unsigned char) rand();
diff --git a/programs/fuzz/fuzz_client.c b/programs/fuzz/fuzz_client.c
index 7ffa7be..270ae8a 100644
--- a/programs/fuzz/fuzz_client.c
+++ b/programs/fuzz/fuzz_client.c
@@ -8,7 +8,9 @@
 #include <stdint.h>
 
 
-#ifdef MBEDTLS_SSL_CLI_C
+#if defined(MBEDTLS_SSL_CLI_C) && \
+    defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C)
 static int initialized = 0;
 #if defined(MBEDTLS_X509_CRT_PARSE_C) && defined(MBEDTLS_PEM_PARSE_C)
 static mbedtls_x509_crt cacert;
@@ -25,11 +27,13 @@
 #endif
 
 const char *pers = "fuzz_client";
-#endif //MBEDTLS_SSL_CLI_C
+#endif /* MBEDTLS_SSL_CLI_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
 
 
 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-#ifdef MBEDTLS_SSL_CLI_C
+#if defined(MBEDTLS_SSL_CLI_C) && \
+    defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C)
     int ret;
     size_t len;
     mbedtls_ssl_context ssl;
@@ -167,7 +171,7 @@
 #else
     (void) Data;
     (void) Size;
-#endif //MBEDTLS_SSL_CLI_C
+#endif /* MBEDTLS_SSL_CLI_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
 
     return 0;
 }
diff --git a/programs/fuzz/fuzz_dtlsclient.c b/programs/fuzz/fuzz_dtlsclient.c
index 8197a64..ff258bc 100644
--- a/programs/fuzz/fuzz_dtlsclient.c
+++ b/programs/fuzz/fuzz_dtlsclient.c
@@ -10,20 +10,27 @@
 #include "mbedtls/timing.h"
 
 
-#ifdef MBEDTLS_SSL_CLI_C
+#if defined(MBEDTLS_SSL_CLI_C) && \
+    defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C) && \
+    defined(MBEDTLS_TIMING_C)
 static int initialized = 0;
 #if defined(MBEDTLS_X509_CRT_PARSE_C) && defined(MBEDTLS_PEM_PARSE_C)
 static mbedtls_x509_crt cacert;
 #endif
 
 const char *pers = "fuzz_dtlsclient";
-#endif // MBEDTLS_SSL_CLI_C
+#endif
 #endif // MBEDTLS_SSL_PROTO_DTLS
 
 
 
 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-#if defined(MBEDTLS_SSL_PROTO_DTLS) && defined(MBEDTLS_SSL_CLI_C)
+#if defined(MBEDTLS_SSL_PROTO_DTLS) && \
+    defined(MBEDTLS_SSL_CLI_C) && \
+    defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C) && \
+    defined(MBEDTLS_TIMING_C)
     int ret;
     size_t len;
     mbedtls_ssl_context ssl;
diff --git a/programs/fuzz/fuzz_dtlsserver.c b/programs/fuzz/fuzz_dtlsserver.c
index 9e9fe8e..4cde1fe 100644
--- a/programs/fuzz/fuzz_dtlsserver.c
+++ b/programs/fuzz/fuzz_dtlsserver.c
@@ -11,7 +11,10 @@
 #include "mbedtls/ssl_cookie.h"
 
 
-#ifdef MBEDTLS_SSL_SRV_C
+#if defined(MBEDTLS_SSL_SRV_C) && \
+    defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C) && \
+    defined(MBEDTLS_TIMING_C)
 const char *pers = "fuzz_dtlsserver";
 const unsigned char client_ip[4] = {0x7F, 0, 0, 1};
 static int initialized = 0;
@@ -19,11 +22,15 @@
 static mbedtls_x509_crt srvcert;
 static mbedtls_pk_context pkey;
 #endif
-#endif // MBEDTLS_SSL_SRV_C
+#endif
 #endif // MBEDTLS_SSL_PROTO_DTLS
 
 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-#if defined(MBEDTLS_SSL_PROTO_DTLS) && defined(MBEDTLS_SSL_SRV_C)
+#if defined(MBEDTLS_SSL_PROTO_DTLS) && \
+    defined(MBEDTLS_SSL_SRV_C) && \
+    defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C) && \
+    defined(MBEDTLS_TIMING_C)
     int ret;
     size_t len;
     mbedtls_ssl_context ssl;
diff --git a/programs/fuzz/fuzz_server.c b/programs/fuzz/fuzz_server.c
index 006239c..014f386 100644
--- a/programs/fuzz/fuzz_server.c
+++ b/programs/fuzz/fuzz_server.c
@@ -9,7 +9,9 @@
 #include <stdint.h>
 
 
-#ifdef MBEDTLS_SSL_SRV_C
+#if defined(MBEDTLS_SSL_SRV_C) && \
+    defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C)
 const char *pers = "fuzz_server";
 static int initialized = 0;
 #if defined(MBEDTLS_X509_CRT_PARSE_C) && defined(MBEDTLS_PEM_PARSE_C)
@@ -25,11 +27,13 @@
 };
 const char psk_id[] = "Client_identity";
 #endif
-#endif // MBEDTLS_SSL_SRV_C
+#endif // MBEDTLS_SSL_SRV_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C
 
 
 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-#ifdef MBEDTLS_SSL_SRV_C
+#if defined(MBEDTLS_SSL_SRV_C) && \
+    defined(MBEDTLS_ENTROPY_C) && \
+    defined(MBEDTLS_CTR_DRBG_C)
     int ret;
     size_t len;
     mbedtls_ssl_context ssl;
@@ -179,7 +183,7 @@
 #else
     (void) Data;
     (void) Size;
-#endif //MBEDTLS_SSL_SRV_C
+#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C */
 
     return 0;
 }