Application Data Security

Overview

The security of an application is the key to its success.

HarmonyOS provides three levels of security capabilities: system security, DevEco Studio tool security, and application ecosystem security.

• At the system security layer, HarmonyOS uses security protection technologies, such as integrity protection, vulnerability anti-exploitation, and secure and trusted environment, to support secure running of applications and ensure the security and reliability of their services.
• At the DevEco Studio/tool level, ecosystem applications are created by different developers for a wide range of purposes. In addition to high-quality ecosystem applications, there are also malicious applications for profit-making, black market, fraudulent applications, and malicious marketing advertisement promotion (such as malicious pop-ups). To ensure the security, purity, and controllability of ecosystem applications, HarmonyOS builds an end-to-end secure and controllable ecosystem.
• At the application security ecosystem level, HarmonyOS uses various software and hardware infrastructures to ensure application security. Specifically, sensitive data storage and user privacy protection are implemented by using the following measures:
  • Sensitive data classification: Data is classified by device and data level to protect user data security and ensure correct data flow between distributed devices.
  • File classification: Application data is saved to the system encrypted directories corresponding to the data security level.
  • Asset data encryption: TEE-based security protection and management APIs are provided so that developers can focus on their tasks without worrying about the underlying implementation details.

The following describes sensitive data storage and user privacy protection at the application security ecosystem level.

Risk Levels

HarmonyOS builds a secure application ecosystem based on hierarchical security, including the security level classification of devices and data.

Device Security Levels

Device security levels are classified into SL1 to SL5 based on devices' security capabilities, for example, whether a TEE or a secure storage chip is available. The intelligent wearable is usually a low-security SL1 device, and the mobile phone and the tablet are usually high-security devices.

Data Security Levels

Hierarchical Data Encryption

Hierarchical Data Protection

Different file paths have different attributes and features. The application sandbox protects hierarchical data to prevent malicious path traversal access. In the application file directory, different directories are distinguished based on file encryption types.

• el1: Directory for the data that can be accessed once the device starts. This directory contains device-focused files.
• el2: Directory for the data that can be accessed only after at least one successful unlock operation (by PIN, fingerprint, or facial authentication, or password-free sign-in) upon the start of the device. This directory contains user-focused files.

  Unless otherwise required, application data is placed in the el2 directory for security purposes. The data that needs to be accessed before the screen is unlocked (such as the clock, alarm, and wallpaper data) is placed in the el1 directory. For details, see Obtaining and Modifying Encryption Levels.

For details about the application file directory, see Application File Directory and Application File Path.

The hierarchical data file path is the common file path of the application. The code for obtaining the path is as follows:

getEl2Path(): void {
  let context = this.getUIContext().getHostContext() as common.UIAbilityContext;
  context.area = contextConstant.AreaMode.EL2;
  let filePath = context.filesDir + '/health_data.txt';
  this.message = filePath;
}

To obtain the el1 path, modify AreaMode. The sample code is as follows:

getEl1Path(): void {
  let context = this.getUIContext().getHostContext() as common.UIAbilityContext;
  context.area = contextConstant.AreaMode.EL1;
  let filePath = context.filesDir + '/health_data.txt';
  this.message = filePath;
}

Unless otherwise required, application data is placed in the el2 directory for security purposes.

The system provides four file-level encryption types to protect files. The application can save files to the corresponding data directories as required. The following table lists the hierarchical encryption policies.

Data Encryption Algorithm

OpenHarmony Universal KeyStore (HUKS) provides platform-level key management for services, including key generation, import, destruction, attestation, agreement, derivation, encryption/decryption, signature/signature verification, and access control. HUKS is the basic security capability of the system. Services can securely and conveniently use the key lifecycle management capability provided by HUKS without implementing complex cryptographic algorithms and key access control models, ensuring the security of sensitive service data.

For details, see Introduction to Universal Keystore Kit.

Data Security Cases

Health data is common sensitive data in daily life and is widely used in HarmonyOS devices, such as mobile phones and watches. The following describes how to store and protect health check reports.

Scenario Design

Health check data is classified as high-risk data based on data classification rules. Therefore, in a program design process, in addition to a protection measure of hierarchical data encryption, secondary encryption needs to be performed to enhance data security. Specifically, the data may be first encrypted once, and then the encrypted data is processed by using a hierarchical data encryption method. This is to improve data confidentiality and integrity and effectively prevent potential data leakage and unauthorized access. With such multi-level encryption measures, health check data can be stored and transmitted more securely and reliably.

The program scenarios consist of the health checklist page, data entry page, and data details page, as shown in the following figure.

Figure 1 Scenario design diagram

Scenario Development

Code Implementation

• Data read and write with hierarchical encryption

Summary

Data security is critical to application development and must be considered in analysis, evaluation, design, and development phases.

• Perform comprehensive risk assessment and classification analysis on various types of data involved in applications, and determine corresponding security protection policies based on the sensitivity and importance of the data.
• Use hierarchical data protection and proper encryption algorithm specifications to prevent sensitive data leakage.

In this document, security levels of data in the health check report are classified and corresponding encryption is performed.

• Data security classification is a way to protect data importance and sensitivity. You can classify data, take security measures, and select appropriate hierarchical data protection policies based on service scenarios to simplify data management and improve data security. For example, you can use strict access control policies to prevent unauthorized access and leakage of sensitive personal privacy data.
• Data encryption technology protects data confidentiality. You need to select proper encryption algorithms and specifications to balance security and computing complexity and ensure normal use of the data. You also need to consider data transmission encryption and storage encryption.

In actual application development, you need to pay attention to data security and continuously improve data security protection measures to ensure that user data security and privacy are effectively protected.

Sample Code

• Application Data Security