feat(plugin): add File encryption plugin (#1509)

* feat(plugin): File encryption

fix #618

* typo

src/@ionic-native/plugins/file-encryption/index.ts

@@ -0,0 +1,52 @@
+import { Plugin, Cordova, IonicNativePlugin } from '@ionic-native/core';
+import { Injectable } from '@angular/core';
+
+/**
+ * @name File Encryption
+ * @description
+ * Simple file encryption for Cordova.
+ *
+ * @usage
+ * ```typescript
+ * import { FileEncryption } from '@ionic-native/file-encryption';
+ *
+ *
+ * constructor(private fileEncryption: FileEncryption) { }
+ *
+ * ...
+ *
+ * this.fileEncryption.decrypt('assets/json/topSecret.json', 'secretKey');
+ *
+ * this.fileEncryption.encrypt('assets/json/topSecret.json', 'secretKey');
+ *
+ * ```
+ */
+@Plugin({
+  pluginName: 'FileEncryption',
+  plugin: 'cordova-safe',
+  pluginRef: 'cordova.plugins.disusered',
+  repo: 'https://github.com/disusered/cordova-safe',
+  platforms: ['Android', 'iOS']
+})
+@Injectable()
+export class FileEncryption extends IonicNativePlugin {
+
+  /**
+   * Enrcypt a file
+   * @param file {string} A string representing a local URI
+   * @param key {string} A key for the crypto operations
+   * @return {Promise<any>} Returns a promise that resolves when something happens
+   */
+  @Cordova()
+  encrypt(file: string, key: string): Promise<any> { return; }
+
+  /**
+   * Decrypt a file
+   * @param file {string} A string representing a local URI
+   * @param key {string} A key for the crypto operations
+   * @return {Promise<any>} Returns a promise that resolves when something happens
+   */
+  @Cordova()
+  decrypt(file: string, key: string): Promise<any> { return; }
+
+}