esp_rom: Add initial ESP32-C3 support

From internal commit 7761d6e8

components/esp_rom/include/esp32c3/rom/rsa_pss.h

@@ -0,0 +1,46 @@
+// 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.
+
+#ifndef _ROM_RSA_PSS_H_
+#define _ROM_RSA_PSS_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define ETS_SIG_LEN 384 /* Bytes */
+#define ETS_DIGEST_LEN 32 /* SHA-256, bytes */
+
+typedef struct {
+    uint8_t n[384]; /* Public key modulus */
+    uint32_t e;     /* Public key exponent */
+    uint8_t rinv[384];
+    uint32_t mdash;
+} ets_rsa_pubkey_t;
+
+bool ets_rsa_pss_verify(const ets_rsa_pubkey_t *key, const uint8_t *sig, const uint8_t *digest);
+
+void ets_mgf1_sha256(const uint8_t *mgfSeed, size_t seedLen, size_t maskLen, uint8_t *mask);
+
+bool ets_emsa_pss_verify(const uint8_t *encoded_message, const uint8_t *mhash);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif