Tokenized Healthcare
Identity Interchange
Cryptography

A protocol for exchanging hashed patient identifiers between two parties without requiring either party to share PII, depend on a shared vendor, or trust the other unilaterally.

SHA-256 AES-256-GCM HKDF-SHA256

What THIIC is

THIIC is a protocol, not a platform. It composes four standard cryptographic primitives — SHA-256, HKDF, AES-256-GCM, ED25519 — in a bilateral salting configuration that lets two parties exchange hashed patient identifiers without either party possessing enough cryptographic context to act alone.

The protocol was designed for healthcare data partnerships. Bilateral exchanges between a data licensor and an activation partner, with audit and compliance as first-class concerns.

THIIC is not new cryptography. It is a configuration of proven primitives, optimized for a specific shape of partnership.

Architecture

┌─────────────────┐      ┌──────────────┐      ┌─────────────────┐
│     SENDER      │  ──  │     WIRE     │  ──  │   RECIPIENT     │
│                 │      │              │      │                 │
│  1. HASH        │      │  3. TRANSMIT │      │  4. DERIVE KEY  │
│  2. WRAP        │      │              │      │  5. UNWRAP      │
└────────┬────────┘      └──────────────┘      └────────┬────────┘
         │                                            │
         │            BILATERAL KEY                    │
         └──────────────────┬─────────────────────────┘
                            │
                      K_sender & S_recipient

Five operations, two environments, one transit. No PII crosses. No party acts alone.

Properties

Multi-Stack Flexibility

Activate through any identity platform — Epsilon, LiveRamp-equivalent translation, DSP-native graphs, internal clean rooms. The data ships clean. Activation is the partner's choice.

Zero PII Movement

Identifiable information never crosses between parties. Only encrypted tokens that resolve to deterministic SHA-256 hashes. HIPAA-safe by design.

Bilateral Trust Model

The salt is split between sender and recipient. Neither party can decrypt unilaterally. A breach of one side leaves the other side's data cryptographically opaque.

Audit-Ready Compliance

Cryptographically signed bilateral audit logs. Both parties can prove what data moved, when, and to whom. BAA-compatible, SOC 2-defensible.

See it run

A working demonstration of the protocol — real cryptography, synthetic patient data, full bilateral flow from hashing through activation simulation. Built for technical evaluation.

Open the demo

Technical reference

The full protocol specification, security model, and industry comparison. Three pages. Forwardable to technical teams.

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Origin

THIIC was developed by Summit Audience Segments as the bilateral data exchange protocol underlying every Summit data licensing agreement. The protocol is not separately licensed — it ships with every Summit license at no additional cost.

Summit operates a 20-year exclusive license on proprietary healthcare data covering 12.17M condition-confirmed patients. THIIC is how that data moves.

Learn about Summit Audience Segments →