# 8.5 eSIM Identity & Device Migration

*Binding telecom identity to cryptographic authority*

> This section explains how PTERI integrates with eSIM infrastructure to prevent fraud, bind Web2 accounts to cryptographic wallets, and enable secure device migration.

***

### Overview

In this model:

* A Web2 account is linked to a wallet address.
* That wallet address is bound to an **eSIM (eSIM A)**.
* The eSIM acts as a continuity signal across devices.
* Device verification is performed using signed messages — not shared secrets.

This allows:

* Strong fraud prevention
* Device-based identity
* Secure migration
* No reliance on passwords

***

<figure><img src="https://4228504584-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FJn0UkERqF0RJQReQlLo9%2Fuploads%2Fg9QBpk2JGrUTtyp1CJFQ%2Fimage.png?alt=media&#x26;token=098af98e-56bb-4a3b-aef8-2e44bab889af" alt=""><figcaption><p>WORKING OF eSIM </p></figcaption></figure>

## Flowchart 1 — How the eSIM Verification Works

### Initial Setup

#### Step 1 — Account Binding

* User has a Web2 account.
* That account is linked to a wallet address.
* The wallet is associated with eSIM A.

Result:

```
Web2 Account → Wallet Address → eSIM A
```

***

#### Step 2 — Authentication Request

On a mobile phone with:

* PTERI Wallet installed
* eSIM A active

The phone initiates an authentication request.

Instead of generating a normal OTP, the device:

* Signs a message using the wallet’s private key.
* Generates an OTP derived from that signed message.
* Sends the signed payload to the server.

***

#### Step 3 — Server Verification

The server:

* Receives the signed message
* Verifies the signature using the wallet address
* Confirms the wallet matches the Web2 account
* Confirms eSIM binding

If valid:

* The device becomes a **VERIFIED PHONE**
* Future authentication can use the same signature-based OTP mechanism

***

<figure><img src="https://4228504584-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FJn0UkERqF0RJQReQlLo9%2Fuploads%2F0AChw50GhofXDSO2CHzm%2Fimage.png?alt=media&#x26;token=e247b87f-edc3-4d27-b2e0-83429b52aeec" alt=""><figcaption><p>SOLUTION TO FRAUD &#x26; DEVICE MIGRATION</p></figcaption></figure>

## Flowchart 2 — Fraud Prevention & Device Migration

This section describes two migration scenarios.

***

### Scenario 1 — Old Device Available

You have:

* Old Mobile Phone (Verified + eSIM A)
* New Mobile Phone (Unverified)

#### Step 1 — Initiate Registration

On the old verified device:

* User requests to register new device.
* Device signs a migration message using its wallet.
* Server receives the signed request.

#### Step 2 — Server Validation

Server verifies:

* Signature matches wallet
* Wallet matches Web2 account
* Request originates from a verified device

#### Step 3 — Register New Device

Server:

* Registers the new device
* Marks it as verified
* Optionally revokes the old device (if requested)

Result:

```
New Mobile Phone → VERIFIED
```

No passwords.\
No SMS.\
No shared secrets.

***

### Scenario 2 — Old Device Lost

You have:

* Only a New Mobile Phone

***

#### Step 1 — Install PTERI Wallet

User downloads the PTERI Wallet on the new device.

***

#### Step 2 — Import Wallet

User imports wallet using:

* Mnemonics (manual backup)
* Or encrypted backup (iCloud / Drive, if enabled)

This restores wallet authority locally.

***

#### Step 3 — Identity Authentication

The wallet:

* Signs an authentication message
* Sends it to the server
* Proves control of the wallet

Server verifies signature.

***

#### Step 4 — Re-establish OTP

The wallet re-initializes the signature-based OTP mechanism.

***

#### Step 5 — Register New Device

Wallet sends a signed registration request.

Server:

* Validates signature
* Confirms wallet continuity
* Registers new device
* Marks device as VERIFIED

Migration complete.

***

## Why This Prevents Fraud

This system eliminates:

* SIM-swap-only attacks
* OTP interception
* Shared-secret replay
* Password resets
* Phishing-based takeover

Because:

* Authority always requires wallet signature
* OTP is derived from signed message
* Server never trusts telecom signals alone
* eSIM acts as continuity signal — not sole authority

***

## Security Model Summary

| Layer               | Purpose                                                        |
| ------------------- | -------------------------------------------------------------- |
| Wallet Signature    | Proves authority                                               |
| eSIM Binding        | Proves continuity                                              |
| Server Verification | Enforces policy                                                |
| Litecoin            | Provides deterministic verification & optional block anchoring |

No single layer can take over the system.

***

## Design Principles

* No private keys stored on server
* No plaintext mnemonics transmitted
* No reliance on SMS OTP
* Device authority is always cryptographic
* Migration requires explicit proof of wallet control

***

## Why This Model Matters

This approach bridges:

* Web2 identity systems
* Telecom infrastructure
* Decentralized cryptographic authority

It allows enterprises to:

* Upgrade security without replacing Web2 accounts
* Prevent SIM-swap fraud
* Enable seamless device migration
* Maintain non-custodial control