diff --git a/configure.ac b/configure.ac
index 753457d48..bf5a27fbe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -192,6 +192,18 @@ AC_ARG_ENABLE([maxstrength],
     [ENABLED_MAXSTRENGTH=no])
 
 
+# Harden, enable Timing Resistance and Blinding by default
+AC_ARG_ENABLE([harden],
+    [AS_HELP_STRING([--enable-harden],[Enable Hardened build, Enables Timing Resistance and Blinding (default: enabled)])],
+    [ENABLED_HARDEN=$enableval],
+    [ENABLED_HARDEN=yes])
+
+if test "$ENABLED_HARDEN" = "yes"
+then
+    AM_CFLAGS="$AM_CFLAGS -DTFM_TIMING_RESISTANT -DECC_TIMING_RESISTANT -DWC_RSA_BLINDING"
+fi
+
+
 # IPv6 Test Apps
 AC_ARG_ENABLE([ipv6],
     [  --enable-ipv6           Enable testing of IPV6 (default: disabled)],
diff --git a/mcapi/crypto.c b/mcapi/crypto.c
index b73ff2772..c8a99f579 100644
--- a/mcapi/crypto.c
+++ b/mcapi/crypto.c
@@ -536,7 +536,22 @@ int CRYPT_RSA_EncryptSizeGet(CRYPT_RSA_CTX* rsa)
         return BAD_FUNC_ARG;
 
     return RsaEncryptSize((RsaKey*)rsa->holder);
-}    
+}
+
+
+int CRYPT_RSA_SetRng(CRYPT_RSA_CTX* rsa, CRYPT_RNG_CTX* rng)
+{
+    if (rsa == NULL)
+        return BAD_FUNC_ARG;
+
+#ifdef WC_RSA_BLINDING
+    return wc_RsaSetRNG((RsaKey*)rsa->holder, (WC_RNG*)rng);
+#else
+    (void)rng;
+
+    return 0;
+#endif
+}
 
 
 /* ECC init */
diff --git a/mcapi/crypto.h b/mcapi/crypto.h
index 36232a452..8fe323631 100644
--- a/mcapi/crypto.h
+++ b/mcapi/crypto.h
@@ -220,7 +220,8 @@ int CRYPT_RSA_PrivateDecrypt(CRYPT_RSA_CTX*, unsigned char*,
                              unsigned int, const unsigned char*, unsigned int);
 
 /* helpers */
-int CRYPT_RSA_EncryptSizeGet(CRYPT_RSA_CTX*);                             
+int CRYPT_RSA_EncryptSizeGet(CRYPT_RSA_CTX*);
+int CRYPT_RSA_SetRng(CRYPT_RSA_CTX*, CRYPT_RNG_CTX*);
 
 
 
diff --git a/mcapi/mcapi_test.c b/mcapi/mcapi_test.c
index a34834d17..0a6d77e74 100644
--- a/mcapi/mcapi_test.c
+++ b/mcapi/mcapi_test.c
@@ -1296,6 +1296,12 @@ static int check_rsa(void)
         return -1;
     }
 
+    ret = CRYPT_RSA_SetRng(&mcRsa, &mcRng);
+    if (ret != 0) {
+        printf("mcapi rsa set rng failed\n");
+        return -1;
+    }
+
     ret = CRYPT_RSA_PublicEncrypt(&mcRsa, out1, sizeof(out1), ourData,
                                   RSA_TEST_SIZE, &mcRng);
     if (ret < 0) {
diff --git a/wolfcrypt/user-crypto/include/user_rsa.h b/wolfcrypt/user-crypto/include/user_rsa.h
index fbf9430fe..72d2c610e 100644
--- a/wolfcrypt/user-crypto/include/user_rsa.h
+++ b/wolfcrypt/user-crypto/include/user_rsa.h
@@ -105,6 +105,7 @@ WOLFSSL_API int  wc_RsaPublicKeyDecodeRaw(const byte* n, word32 nSz,
 #endif
 WOLFSSL_API int  wc_RsaFlattenPublicKey(RsaKey*, byte*, word32*, byte*,
                                                                        word32*);
+WOLFSSL_API int  wc_RsaSetRNG(RsaKey* key, WC_RNG* rng);
 
 
 #if defined(WOLFSSL_CERT_GEN) || defined(WOLFSSL_KEY_GEN)
diff --git a/wolfcrypt/user-crypto/src/rsa.c b/wolfcrypt/user-crypto/src/rsa.c
index 748c420c4..974789ce7 100644
--- a/wolfcrypt/user-crypto/src/rsa.c
+++ b/wolfcrypt/user-crypto/src/rsa.c
@@ -2670,5 +2670,19 @@ int wc_RsaKeyToPublicDer(RsaKey* key, byte* output, word32 inLen)
 
 #endif /* WOLFSSL_KEY_GEN */
 
+#ifdef WC_RSA_BLINDING
+
+int wc_RsaSetRNG(RsaKey* key, WC_RNG* rng)
+{
+    if (key == NULL)
+        return USER_CRYPTO_ERROR;
+
+    (void)rng;
+
+    return 0;
+}
+
+#endif /* WC_RSA_BLINDING */
+
 #endif /* NO_RSA */
 
diff --git a/wolfssl/wolfcrypt/settings.h b/wolfssl/wolfcrypt/settings.h
index c2130f6a2..ad95b6137 100644
--- a/wolfssl/wolfcrypt/settings.h
+++ b/wolfssl/wolfcrypt/settings.h
@@ -155,6 +155,8 @@
 /* make sure old RNG name is used with CTaoCrypt FIPS */
 #ifdef HAVE_FIPS
     #define WC_RNG RNG
+    /* blinding adds API not available yet in FIPS mode */
+    #undef WC_RSA_BLINDING
 #endif