Wi-Fi improvements (#77)

Refactoring, new features and stability improvements.

tactility-core/src/hash.c

@@ -9,3 +9,16 @@ uint32_t tt_hash_string_djb2(const char* str) {
     }
     return hash;
 }
+
+uint32_t tt_hash_bytes_djb2(const void* data, size_t length) {
+    uint32_t hash = 5381;
+    uint8_t* data_bytes = (uint8_t*)data;
+    uint8_t c = *data_bytes++;
+    size_t index = 0;
+    while (index < length) {
+        hash = ((hash << 5) + hash) + (uint32_t)c; // hash * 33 + c
+        c = *data_bytes++;
+        index++;
+    }
+    return hash;
+}

tactility-core/src/hash.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <stddef.h>
 #include <stdint.h>
 
 #ifdef __cplusplus
@@ -7,13 +8,19 @@ extern "C" {
 #endif
 
 /**
- * This is quicker than the m-string.h hashing, as the latter
- * operates on raw memory blocks and thus a strlen() call is required first.
+ * Implementation of DJB2 hashing algorithm.
  * @param[in] str the string to calculate the hash for
  * @return the hash
  */
 uint32_t tt_hash_string_djb2(const char* str);
 
+/**
+ * Implementation of DJB2 hashing algorithm.
+ * @param[in] data the bytes to calculate the hash for
+ * @return the hash
+ */
+uint32_t tt_hash_bytes_djb2(const void* data, size_t length);
+
 #ifdef __cplusplus
 }
 #endif

tactility-core/src/secure.c

@@ -120,17 +120,19 @@ static void get_key(uint8_t key[32]) {
 #endif
 }
 
-void tt_secure_get_iv_from_string(const char* input, uint8_t iv[16]) {
+void tt_secure_get_iv_from_data(const void* data, size_t data_length, uint8_t iv[16]) {
     memset((void*)iv, 0, 16);
-    char c = *input++;
-    int index = 0;
-    while (c) {
-        iv[index] = c;
-        index++;
-        c = *input++;
+    uint8_t* data_bytes = (uint8_t*)data;
+    for (int i = 0; i < data_length; ++i) {
+        size_t safe_index = i % 16;
+        iv[safe_index] %= data_bytes[i];
     }
 }
 
+void tt_secure_get_iv_from_string(const char* input, uint8_t iv[16]) {
+    tt_secure_get_iv_from_data((const void*)input, strlen(input), iv);
+}
+
 static int tt_aes256_crypt_cbc(
     const uint8_t key[32],
     int mode,

tactility-core/src/secure.h

@@ -26,7 +26,15 @@ extern "C" {
 #endif
 
 /**
- * @brief Fills the IV with zeros and then copies up to 16 characters of the string into the IV.
+ * @brief Fills the IV with zeros and then creates an IV based on the input data.
+ * @param data input data
+ * @param data_length input data length
+ * @param iv output IV
+ */
+void tt_secure_get_iv_from_data(const void* data, size_t data_length, uint8_t iv[16]);
+
+/**
+* @brief Fills the IV with zeros and then creates an IV based on the input data.
  * @param input input text
  * @param iv output IV
  */