A verified number isn't a verified identity.
OTP confirms a number can receive a code. It never confirms the SIM is still in your customer's phone, or that this is the same SIM and device you onboarded. Sign3 SIM Binding closes that gap, silently, on every sensitive action.
Why OTP Isn't Enough
The number can stay the same while the SIM changes.
A SIM swap or replacement can redirect OTPs to another device. Successful code delivery alone doesn't establish that the current mobile setup is the one you originally trusted.
- 01
See beyond code delivery
OTP shows that a code reached a channel. SIM Binding adds context about the mobile subscription and its relationship to the device or app environment.
- 02
Spot relevant changes
Where supported, surface inconsistencies in the expected SIM and device relationship for further risk assessment.
- 03
Make informed decisions
Use the signal within your existing controls to support step-up verification, review, hold or block decisions based on your thresholds.
How It Works
From mobile signals to the right action.
Bring mobile identity context into your existing risk decision process.
01 — Bind
Establish the expected setup
At onboarding, establish the relevant relationship between the mobile subscription, device and app environment using supported methods.
02 — Check
Assess sensitive activity
Evaluate available signals when a customer logs in, registers a device or takes another sensitive action.
03 — Flag
Surface a change
Where supported, identify a relevant change or mismatch that may warrant closer scrutiny.
04 — Act
Apply your risk rules
Feed the signal into your existing fraud flow for step-up, hold, review or block decisions.
The Silent Bind, Step by Step
No OTP. No code to phish, forward, or intercept.
The SIM proves itself to the network, and the network returns the result.
- 01
Initiation
The customer enters their mobile number in your app, during onboarding or a sensitive action.
- 02
Cellular routing
The request runs over the device's mobile data connection, not Wi-Fi. The number has to be live on the network for the check to run.
- 03
Cryptographic handshake
The network sends a random challenge (RAND) to the SIM, whether physical, eSIM, or iSIM. The SIM and the network each compute a signed response (SRES) from the authentication key (Ki) that never leaves either side.
- 04
Silent verification
The network matches the response and confirms the active SIM maps to the registered number (MSISDN) on that device.
- 05
Bind token
Your bank, PSP, or platform receives a signed bind token and completes the account link. The customer never sees or types a code.
The customer taps once. The SIM does the proving.
Stronger in Combination
One signal is useful. Four, read together, are hard to beat.
- 01
Mobile identity
The SIM, its carrier, and its relationship to the device.
- 02
Device intelligence
A persistent device identity that survives resets and reinstalls.
- 03
Authentication
The result of the verification step the customer just completed.
- 04
Behaviour and transaction
Whether this action fits how this account normally behaves.
Risk decision
SIM Binding feeds the first layer and gains from the other three.
The result is a fuller picture of mobile identity risk, without treating every SIM change as fraud.
Where It Adds Value
Mobile identity context for critical journeys.
- 01
Account access & takeover
Add a mobile identity signal to login and sensitive account actions.
- 02
Digital lending
Assess SIM and device patterns during onboarding and account activity.
- 03
High-value payments
Use relevant changes as an input to risk-based transaction checks.
- 04
Device registration
Establish an expected mobile setup early, where supported.
Sign3 SIM Binding
The number is only part of the identity.
Bring SIM and device context into the decisions that protect your customers. Talk to our team about how SIM Binding can fit into your fraud prevention flow.