What methods are used to implement SSL certificate deployment in Android applications?

SSL certificates in Android applications are implemented in several ways:

1. Using the system certificate store — the app trusts certificates installed in the system.

2. Implementing custom trust store — the app uses its own set of trusted certificates, for example, for working with self-signed certificates.

3. Network Security Configuration — from Android 7.0+ you can configure an XML file to specify which certificates to trust, including the ability to add your own CAs or disable trust for system ones.

4. Programmatic certificate verification — certificates can be checked manually in code, for example, using SSLSocketFactory or TrustManager.

Example of Network Security Configuration (res/xml/network_security_config.xml):

<network-security-config>
    <domain-config cleartextTrafficPermitted="false">
        <trust-anchors>
            <certificates src="system" />
            <certificates src="user" />
        </trust-anchors>
    </domain-config>
</network-security-config>

This allows flexible management of trust for SSL certificates in the app.