### Google’s Play Integrity API and the Future of Sideloading on Android
The practice of sideloading apps on Android has been widely embraced by users looking to install applications outside of the Google Play Store. Whether it’s a beta app, an unsupported service, or simply an application unavailable in certain locales, sideloading enables users to directly install APK files. Nevertheless, recent updates to Google’s Play Integrity API indicate a potential transformation in how sideloading will be approached, which might complicate the process for users aiming to install apps from sources outside the Play Store.
#### The Surge of Sideloading and Google’s Acceptance
Traditionally, sideloading has been an accepted, if not fully encouraged, activity on Android. Users desiring greater command over their devices could seamlessly obtain APKs from external sites and install them directly. This was especially advantageous for individuals utilizing customized Android versions that did not integrate with the Google Play Store or for applications that were no longer supported by their creators.
However, this liberty carries inherent risks. Sideloaded applications could evade Google’s security protocols, potentially leaving users vulnerable to malware or other security risks. Despite these dangers, Google generally adopted a lenient stance, providing advisories without outright prohibiting sideloaded applications.
#### The Play Integrity API: A Fresh Layer of Oversight
That lenient approach is shifting. As noted by [Android Authority](https://www.androidauthority.com/play-integrity-sideloading-detection-3480639/), Google’s Play Integrity API has rolled out new features that permit developers to prompt “remediation” dialogues when users attempt to sideload applications. These dialogues encourage users to fetch the app from the Google Play Store instead, effectively obstructing the installation of sideloaded applications in certain situations.
Users have begun to encounter these prompts within various applications, such as the UK retailer Tesco’s app, the fandom app BeyBlade X, and even ChatGPT. In some instances, these prompts are unavoidable, compelling users to secure the app via the Play Store or forgo its use entirely.
#### How the Play Integrity API Functions
The Play Integrity API enables applications to assess the “integrity” of the device in use. This encompasses confirming if the device possesses a “trustworthy” software environment, if Google Play Protect is operational, and if it meets other security evaluations. Should the device fail these assessments, the app can restrict access or issue alerts.
This mechanism isn’t entirely novel. Applications have previously employed similar techniques to deny access on rooted devices or those configured with custom ROMs. For instance, a widely-used two-factor authentication app recently barred access on rooted phones, including those operating on the security-centric GrapheneOS. However, the newly introduced capabilities in the Play Integrity API extend this further by specifically addressing sideloaded applications.
#### The Discussion Around Google’s Integrity Mechanisms
The debut of these new features has ignited conversations within the Android community. Some, including developers from GrapheneOS, have expressed concerns regarding the accuracy and fairness of Google’s Play Integrity API and its predecessor, SafetyNet Attestation. They contend that these frameworks unjustly penalize users who opt for custom Android versions or who root their devices for valid reasons.
GrapheneOS has even suggested that developers utilize standard Android hardware attestation instead of depending on Google’s proprietary systems. This would permit applications to verify the device’s security without obstructing access solely based on whether the device operates a stock version of Android.
#### The Implications for Developers
For developers, the Play Integrity API presents both advantages and obstacles. On one hand, it offers a mechanism to ensure their applications operate on secure, unaltered devices. This can assist in deterring piracy, safeguarding sensitive information, and guaranteeing that users receive the optimal experience.
Conversely, the API’s stringent enforcement of Play Store downloads may alienate users who favor sideloading or possess devices that lack access to the Play Store. Developers might also miss out on crucial metrics and feedback from users who acquire their apps through unofficial means.
#### Automatic Integrity Protection and “Unknown Distribution Channels”
Google has also rolled out a function termed “Automatic Integrity Protection,” which adds an additional security layer to applications. This function automatically verifies whether an application was sourced from an “unknown distribution channel” and urges users to download it from the Play Store instead. Currently, this feature is accessible to “select Play Partners,” yet it could expand to encompass more applications in the future.
This initiative aligns with a broader movement by Google and Apple to restrict sideloading under the guise of security. Both corporations have contended that sideloading amplifies the potential for malware and other security threats. In fact, Google recently initiated [malware scanning for sideloaded apps](https://arstechnica.com/gadgets/2023/10/android-will-now-scan-sideloaded-apps-for-malware-at-install-time/) at the point of installation, further tightening oversight over the sideloading procedure.
#### The Regulatory Landscape
The
