增加加密

Hardware/Crypto.c

@@ -52,6 +52,29 @@ static uint32_t pkcs7_pad(uint8_t* data, uint32_t data_len, uint32_t buffer_size
     return data_len + padding_len;
 }
 
+static uint32_t pkcs7_unpad(uint8_t* data, uint32_t data_len)
+{
+    uint8_t padding_len;
+    uint32_t i;
+
+    if (data_len == 0) {
+        return 0;
+    }
+
+    padding_len = data[data_len - 1];
+    if (padding_len < 1 || padding_len > 16 || padding_len > data_len) {
+        return data_len;
+    }
+
+    for (i = data_len - padding_len; i < data_len; i++) {
+        if (data[i] != padding_len) {
+            return data_len;
+        }
+    }
+
+    return data_len - padding_len;
+}
+
 uint32_t Crypto_EncryptJSON(const char* json_data, char* encrypted_output)
 {
     uint32_t json_len = strlen(json_data);
@@ -97,3 +120,37 @@ uint32_t Crypto_EncryptJSON(const char* json_data, char* encrypted_output)
 
     return encoded_len;
 }
+
+uint32_t Crypto_DecryptJSON(const char* encrypted_base64, char* plain_output, uint32_t output_size)
+{
+    uint32_t encrypted_len;
+    uint32_t binary_len;
+    uint32_t plain_len;
+    uint8_t buffer[768];
+    struct AES_ctx ctx;
+
+    if (encrypted_base64 == NULL || plain_output == NULL || output_size == 0) {
+        return 0;
+    }
+
+    encrypted_len = strlen(encrypted_base64);
+    if (encrypted_len == 0 || encrypted_len > BASE64_ENCODE_SIZE(sizeof(buffer))) {
+        return 0;
+    }
+
+    binary_len = base64_decode(encrypted_base64, encrypted_len, buffer);
+    if (binary_len == 0 || (binary_len % 16) != 0 || binary_len >= sizeof(buffer)) {
+        return 0;
+    }
+
+    AES_init_ctx_iv(&ctx, AES_KEY, AES_IV);
+    AES_CBC_decrypt_buffer(&ctx, buffer, binary_len);
+    plain_len = pkcs7_unpad(buffer, binary_len);
+    if (plain_len >= output_size) {
+        return 0;
+    }
+
+    memcpy(plain_output, buffer, plain_len);
+    plain_output[plain_len] = '\0';
+    return plain_len;
+}