Silent Network Authentication (SNA) is a carrier-based phone verification method that confirms a user's possession of a mobile number directly through the mobile network, without sending an SMS or requiring the user to enter a code.
SNA is available as a verification method within the Phone Number Input module. It is currently only available for Flows. When enabled, SNA runs as the primary verification method, with SMS OTP as an automatic fallback when SNA is unavailable.
This feature must be enabled for your organization before use. Contact your Incode representative if you are interested in this feature.
How It Works
SNA verifies that the device associated with the provided phone number is active and connected to the mobile network. This validation happens through secure interactions with mobile network operators, establishing a proof of possession tied to the SIM.
The following sequence diagram shows how SNA runs within a verification flow, including coverage checks, carrier validation, and fallback to SMS OTP when required.
Benefits
SNA improves the phone verification experience across three dimensions:
- Low-friction user experience: Users only need to enter their phone number. Verification happens in the background without OTP retrieval or manual input, which reduces user effort and improves completion rates.
- Reliable verification: Removing the dependency on SMS delivery avoids common issues such as message delays, delivery failures, and repeated OTP requests.
- Improved security: Carrier-level validation reduces exposure to SMS-based threats such as phishing, OTP interception, and SIM swap attacks.
Considerations
- Requires mobile network connectivity: SNA relies on communication with the mobile carrier network and will not work if the device has no mobile data connectivity.
- Fallback is required for full coverage: When SNA is not supported due to device, carrier, or connectivity constraints, the flow automatically falls back to SMS OTP to complete verification.
SNA and Identity Verification
SNA provides a real-time signal that a user controls the phone number they are claiming, by validating the association between the device and SIM through the mobile network. On its own, SNA answers foundational questions about phone ownership and device linkage. Combined with other Incode signals such as biometrics, document verification, and device intelligence, it contributes to a more complete view of the user.
This supports stronger identity decisions by helping answer questions such as:
- Does the user control this phone number?
- Is this number actively linked to the device being used?
- Has this phone or device been reused across multiple accounts?
- Is this identity linked to known or previously detected fraud?
- Is this identity part of a suspicious network of users or devices?
These insights are powered by Incode's ability to connect signals across sessions and workflows, supporting detection of repeat fraud, account sharing, and coordinated activity.
For deeper network-level insights and relationship-based risk analysis, SNA can be combined with Trust Graph. Contact your Incode representative for more information.
Implementation
SNA implementation is platform-specific. See the SDK reference for your platform: