xSimGuard: SIM Swap Protection

The Problem

SIM swap attacks redirect phone numbers to attacker-controlled SIMs, bypassing SMS-based MFA. A single social engineering call to one carrier is enough to take over any account.

Mobile phone numbers have become de facto identity anchors. Banks, exchanges, email providers, and social platforms all use SMS as a second factor. A SIM swap at one carrier compromises every account linked to that number.

The FBI reported $68M in SIM swap losses in 2021 alone. High-net-worth individuals and executives are targeted specifically because single-carrier identity is a single point of failure. The attacker only needs to convince one customer service representative.

The Old Way

The PRIVATE.ME Solution

xSimGuard splits mobile identity credentials across multiple independent carriers using XorIDA. Verifying ownership requires K-of-N carrier confirmations. A single SIM swap yields zero usable identity.

Instead of anchoring identity to one phone number at one carrier, xSimGuard distributes identity shares across organizationally independent carriers. Each carrier holds one share that reveals zero information about the credential on its own.

Ownership verification requires threshold confirmation from K carriers simultaneously. An attacker must execute coordinated SIM swaps at multiple carriers — an operationally infeasible attack that requires social engineering separate organizations in parallel.

The New Way

How It Works

Mobile identity credentials are split via XorIDA across N independent carriers. Ownership verification collects K shares, verifies HMAC integrity on each, and reconstructs the credential only when threshold is met.

Use Cases

Integration

import { splitIdentity, verifyOwnership } from '@private.me/xsimguard';

// Split mobile credential across 3 carriers (2-of-3)
const shares = await splitIdentity(
  { phoneNumber: '+1-555-0100', imsi: '310260...' },
  ['carrier-a.api', 'carrier-b.api', 'carrier-c.api'],
  { n: 3, k: 2 }
);

// Verify ownership requires threshold from multiple carriers
const verified = await verifyOwnership(shares, challengeToken);

Viral M2M Onboarding

xSimGuard enables sub-2-minute carrier-to-carrier M2M setup with zero manual configuration. First carrier invites second carrier via DID, second carrier accepts with one API call, and the trust relationship is live. No pre-shared keys, no IT tickets, no coordination calls.

How It Works

Carrier A runs xlink invite carrier-b-did and receives a single-use invitation URL. Carrier B navigates to the URL in their admin dashboard, sees Carrier A's DID and requested scope (e.g., roaming:hlr-sync), and clicks Accept. The M2M trust relationship is established instantly via cryptographic DID verification — no manual key exchange, no email threads, no shared secrets.

const invitation = await generateInvite({
  recipientDID: 'did:key:z6MkCarrierB...',
  scope: 'roaming:hlr-sync',
  threshold: { k: 2, n: 3 }
});

// Share URL with Carrier B (email, SMS, or admin portal)
console.log(invitation.url); // https://carrier-a.api/invite/abc123

const result = await acceptInvite(invitationURL);

// Trust relationship now active — can immediately start roaming auth
const verified = await verifyRoamingSubscriber(imsi, carrierId);

Telecom Use Cases

Cross-Carrier Roaming Authentication

International roaming requires real-time HLR/HSS coordination between carriers. Traditional SS7 signaling is vulnerable to location tracking and subscriber impersonation. xSimGuard splits roaming credentials across the home carrier and visiting carrier (2-of-2), ensuring that neither carrier alone can authenticate a roaming subscriber. An attacker compromising one carrier's HSS gains zero usable authentication capability.

SIM Swap Fraud Prevention ($68B Annually)

SIM swap fraud cost the telecom industry $68 billion in 2021 (FBI data). Attackers social-engineer customer service at one carrier to port a victim's number to an attacker-controlled SIM. With xSimGuard, porting a number requires threshold approval from K-of-N carriers. An attacker must compromise customer service representatives at multiple independent carriers simultaneously — an operationally infeasible attack.

eSIM Provisioning Security

eSIM provisioning involves downloading SIM credentials over-the-air. A compromised provisioning server can issue fraudulent eSIM profiles. xSimGuard splits eSIM credentials across the carrier's provisioning server and a second independent entity (e.g., device manufacturer OEM or third-party HSM provider). The eSIM profile only activates when both shares are present, preventing rogue provisioning even if the carrier's server is compromised.

IoT SIM Security at Scale

IoT deployments use millions of embedded SIMs with long lifecycles (10+ years). A single compromised SIM credential database exposes the entire fleet. xSimGuard splits IoT SIM credentials across the carrier and the IoT platform provider (2-of-2). Fleet-wide credential compromise requires simultaneous breach of both organizations — a security model that scales to billion-device deployments without increasing per-device overhead.

Mobile Money Protection (M-Pesa, GCash, etc.)

Mobile money platforms anchor account access to phone numbers. A SIM swap at the carrier bypasses all account security and enables instant theft. xSimGuard distributes mobile money identity across the telecom carrier and the financial institution operating the mobile money platform (2-of-2). An attacker must compromise both the carrier's customer service and the bank's authentication system to execute theft — a coordinated attack requiring simultaneous social engineering of separate organizations.

2FA Bypass Prevention

SMS-based 2FA is the weakest link in account security because it relies on single-carrier control. A SIM swap at one carrier defeats 2FA for every account using that phone number. xSimGuard upgrades SMS 2FA to multi-carrier threshold verification. The 2FA code is only reconstructable when K-of-N carriers confirm ownership. Existing SMS 2FA infrastructure remains unchanged — xSimGuard operates as a verification layer behind the scenes.

Security Properties

Verifiable Data Protection

Every operation in this ACI produces a verifiable audit trail via xProve. HMAC-chained integrity proofs let auditors confirm that data was split, stored, and reconstructed correctly — without accessing the data itself.

Ready to deploy xSimGuard?

Talk to Ren, our AI sales engineer, or book a live demo with our team.

Ship Proofs, Not Source

xSimguard generates cryptographic proofs of correct execution without exposing proprietary algorithms. Verify integrity using zero-knowledge proofs — no source code required.

Use Cases