diff --git a/components/mbedtls/port/esp_bignum.c b/components/mbedtls/port/esp_bignum.c
index eb18988f49..3e1415059c 100644
--- a/components/mbedtls/port/esp_bignum.c
+++ b/components/mbedtls/port/esp_bignum.c
@@ -32,6 +32,7 @@
 #include "esp_log.h"
 #include "esp_attr.h"
 #include "bignum_impl.h"
+#include "soc/rsa_caps.h"
 
 #include <mbedtls/bignum.h>
 
@@ -301,7 +302,7 @@ int mbedtls_mpi_exp_mod( mbedtls_mpi *Z, const mbedtls_mpi *X, const mbedtls_mpi
         return mbedtls_mpi_lset(Z, 1);
     }
 
-    if (num_words * 32 > 4096) {
+    if (num_words * 32 > SOC_RSA_MAX_BIT_LEN) {
         return MBEDTLS_ERR_MPI_NOT_ACCEPTABLE;
     }
 
@@ -403,8 +404,8 @@ int mbedtls_mpi_mul_mpi( mbedtls_mpi *Z, const mbedtls_mpi *X, const mbedtls_mpi
        multiplication doesn't have the same restriction, so result is simply the
        number of bits in X plus number of bits in in Y.)
     */
-    if (hw_words * 32 > 2048) {
-        if (z_words * 32 <= 4096) {
+    if (hw_words * 32 > SOC_RSA_MAX_BIT_LEN/2) {
+        if (z_words * 32 <= SOC_RSA_MAX_BIT_LEN) {
             /* Note: it's possible to use mpi_mult_mpi_overlong
                for this case as well, but it's very slightly
                slower and requires a memory allocation.
diff --git a/components/soc/soc/esp32/include/soc/rsa_caps.h b/components/soc/soc/esp32/include/soc/rsa_caps.h
new file mode 100644
index 0000000000..475dc4fe8b
--- /dev/null
+++ b/components/soc/soc/esp32/include/soc/rsa_caps.h
@@ -0,0 +1,26 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+#define SOC_RSA_MAX_BIT_LEN    (4096)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/components/soc/soc/esp32s2/include/soc/rsa_caps.h b/components/soc/soc/esp32s2/include/soc/rsa_caps.h
new file mode 100644
index 0000000000..475dc4fe8b
--- /dev/null
+++ b/components/soc/soc/esp32s2/include/soc/rsa_caps.h
@@ -0,0 +1,26 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+#define SOC_RSA_MAX_BIT_LEN    (4096)
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/components/soc/soc/esp32s3/include/soc/rsa_caps.h b/components/soc/soc/esp32s3/include/soc/rsa_caps.h
new file mode 100644
index 0000000000..475dc4fe8b
--- /dev/null
+++ b/components/soc/soc/esp32s3/include/soc/rsa_caps.h
@@ -0,0 +1,26 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+#define SOC_RSA_MAX_BIT_LEN    (4096)
+
+#ifdef __cplusplus
+}
+#endif