Merge branch 'feature/add_rc4_algorithm_in_util' into 'master'

feat(util): Add ARC4 for ESP8266 SoC

See merge request sdk/ESP8266_RTOS_SDK!1028

components/util/include/esp_arc4.h

@@ -0,0 +1,71 @@
+// Copyright 2018-2019 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
+
+#include <stdint.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+/**
+ * @brief                       ARC4 context structure
+ */
+typedef struct
+{
+    int x;                      /*!< permutation index */
+    int y;                      /*!< permutation index */
+    unsigned char m[256];       /*!< permutation table */
+}esp_arc4_context;
+
+/**
+ * @brief          ARC4 key schedule
+ *
+ * @param ctx      ARC4 context to be setup
+ * @param key      the secret key
+ * @param keylen   length of the key, in bytes
+ */
+void esp_arc4_setup(esp_arc4_context *ctx, const uint8_t *key, uint32_t keylen);
+
+/**
+ * @brief          ARC4 cipher function
+ *
+ * @param ctx      ARC4 context
+ * @param length   length of the input data
+ * @param input    buffer holding the input data
+ * @param output   buffer for the output data
+ *
+ * @return         0 if successful
+ */
+int esp_arc4_encrypt(esp_arc4_context *ctx, size_t length, const uint8_t *input, uint8_t *output);
+
+/**
+ * @brief          ARC4 cipher function
+ *
+ * @param ctx      ARC4 context
+ * @param length   length of the input data
+ * @param input    buffer holding the input data
+ * @param output   buffer for the output data
+ *
+ * @return         0 if successful
+ * @Note           When you encrypt or decrypt, must call esp_arc4_setup function to set key. 
+ *                 Encrypt and decrypt will change the ctx value
+ */
+int esp_arc4_decrypt(esp_arc4_context *ctx, size_t length, const uint8_t *input, uint8_t *output );
+
+#ifdef __cplusplus
+}
+#endif
+