docs rewrite

docs/identity-solutions/biometrics/introduction.mdx

@@ -0,0 +1,74 @@
+---
+title: Confidential Biometrics
+description: Biometric matching and verification in MPC - no plaintext biometric data exposed
+---
+
+# Confidential Biometrics
+
+Confidential Biometrics is enabled by [TACEO:Match](/docs/taceo-match/overview), TACEO's service for biometric feature matching in MPC. No plaintext biometric data leaves the user's
+device or passes through a single party. TACEO's threshold MPC stack evaluates biometric
+comparisons directly on secret shares, so the underlying templates are never reconstructed by
+any node, any server, or TACEO itself.
+
+:::tip Proven at global scale
+TACEO co-architected the MPC protocol now running **World**'s iris-code uniqueness system in
+production at global scale. The same threshold computation model - secret-share the sensitive
+data, compute on shares, verify the result - is the foundation Confidential Biometrics is built
+on.
+:::
+
+## Why biometrics are different
+
+Biometric data is unlike a password or a private key. You can rotate a key; you cannot rotate
+your iris or your palm.
+
+- **Irrevocable.** A leaked biometric template exposes a user forever. There is no recovery
+  path equivalent to "change your password."
+- **Population-scale damage.** Centralized biometric databases are prime target for attacks.
+- **Device-only matching is limiting.** Keeping templates on device protects privacy but
+  blocks the cross-organization checks that matter most: uniqueness across a system, sybil
+  detection, sanctions screening.
+- **Central servers break the trust model.** Sending raw templates to a verification server
+  requires trusting that server completely - with data that can never be changed if trust is
+  violated.
+
+Any architecture that solves these problems needs to run the comparison without ever
+centralizing the template in plaintext. That is exactly what MPC enables.
+
+## How MPC solves it
+
+The core mechanic: a biometric template is split into cryptographic secret shares and
+distributed across independent MPC nodes on the TACEO Network. No single node holds a
+meaningful fragment of the template. Comparison, matching, and uniqueness checks are then
+computed *on the shares directly*.
+
+**Step by step:**
+
+1. **Template enrollment.** The biometric template (e.g. an iris code) is secret-shared on
+   the user's device or dedicated hardware before it leaves. The shares are distributed to the MPC network.
+   No complete template exists outside the device.
+
+2. **Matching in MPC.** When verification is requested, the MPC nodes cooperate to evaluate
+   the comparison function (e.g. Hamming distance for iris codes) on their respective shares. Each node only ever sees its own share; the
+   comparison result is the only output.
+
+3. **Threshold security.** Templates are protected by the threshold assumption we know from MPC protocols.
+
+## What this enables
+
+| Use case | Why MPC makes it possible |
+|---|---|
+| **Population-scale uniqueness / sybil resistance** | Compare against an enrolled set without centralizing templates or revealing which record matched |
+| **Cross-org deduplication** | Organizations contribute to a joint check without sharing their underlying biometric data with each other |
+| **Anonymous identity verification** | Prove a biometric matches an enrolled identity without revealing *which* identity |
+
+## Underlying service
+
+The low-level concepts and service documentation live under
+[TACEO:Match](/docs/taceo-match/overview) in the TACEO Services section.
+
+For adjacent reading:
+- [Identity Solutions overview](/docs/identity-solutions/overview)
+- [Distributed Nullifiers](/docs/identity-solutions/nullifiers/introduction) - TACEO's
+  production OPRF-based nullifier service, same threshold MPC foundation
+- [Identity & Uniqueness use cases](/docs/use-cases/identity)

docs/taceo-oprf/quickstart.mdx → docs/identity-solutions/nullifiers/getting-started/quickstart.mdx

@@ -139,7 +139,7 @@ The wallet ownership example uses **two zero-knowledge proofs**:
 ## Next Steps
 
 ### Experiment Locally
-Ready to experiment more? Set up your own [local OPRF network](/docs/taceo-oprf/quicklocal) for development.
+Ready to experiment more? Set up your own [local OPRF network](/docs/identity-solutions/nullifiers/getting-started/quicklocal) for development.
 
 ### Custom Authorization
 Want to build your own authorization logic? Learn about [Authorization Modules](/docs/taceo-oprf/authorization).

docs/identity-solutions/nullifiers/introduction.mdx

@@ -0,0 +1,24 @@
+---
+title: Distributed Nullifiers
+description: Threshold-secured deterministic nullifiers via TACEO:OPRF
+---
+
+# Distributed Nullifiers
+
+Distributed Nullifiers is enabled by [TACEO:OPRF](/docs/taceo-oprf/overview). TACEO's production service for computing threshold Oblivious Pseudo-Random Functions (OPRFs).
+
+A nullifier derived from a single secret is only as safe as that secret. TACEO's distributed
+approach requires a threshold of independent MPC nodes to cooperate before any nullifier can be
+evaluated, so no single party - including TACEO - can link or deanonymize your users even if user secrets are compromised partially compromised. Beyond nullifiers, TACEO:OPRF can serve any use case requiring distributed, verifiable pseudorandomness.
+
+In production for [**World**](https://world.org/blog/announcements/world-id-full-stack-proof-of-human) and **zkPassport**.
+
+## Getting started
+
+Follow the [Quickstart](/docs/identity-solutions/nullifiers/getting-started/quickstart) to run
+your first OPRF computation against the live testnet in minutes.
+
+## Underlying service
+
+The low-level API, authorization modules, and concepts documentation live under
+[TACEO:OPRF](/docs/taceo-oprf/overview) in the TACEO Services section.

docs/identity-solutions/overview.mdx

@@ -0,0 +1,61 @@
+---
+title: Identity Solutions Overview
+description: Privacy-preserving identity at global scale, powered by the TACEO Network
+---
+
+import Link from "@docusaurus/Link";
+
+# Identity Solutions on the TACEO Network
+
+TACEO's identity solutions power privacy-preserving identity systems at global scale.
+TACEO:OPRF is in production and trusted by partners including **World** and **zkPassport**, providing the
+backbone for anonymous, sybil-resistant identity verification.
+
+These solutions let developers build identity systems that verify without surveilling: nullifiers
+that can't be correlated, passport attributes that can be matched without exposure, and biometric
+checks that leave no plaintext trail.
+
+## Solutions
+
+<div style={{display: 'grid', gridTemplateColumns: 'repeat(auto-fit, minmax(300px, 1fr))', gap: '2rem', marginTop: '2rem'}}>
+
+<div className="service-card-primary">
+
+### Distributed Nullifiers
+
+Privacy-preserving deterministic nullifiers computed by a threshold of independent MPC nodes.
+No single party can evaluate or link nullifiers on its own.
+
+**Best fit:**
+
+- ZK identity systems (like World ID) that need threshold-secured nullifiers
+- Anonymous voting and private credential systems
+- Wallet recovery without custodial key exposure
+
+[Learn more →](/docs/identity-solutions/nullifiers/introduction)
+
+</div>
+
+<div className="service-card-muted">
+
+### Threshold Passport Identification
+
+Match passport attributes across parties without revealing the underlying document data.
+Built on the same MPC network TACEO co-architected for zkPassport.
+
+[Learn more →](/docs/identity-solutions/passport-identification/introduction)
+
+</div>
+
+<div className="service-card-muted">
+
+### Confidential Biometrics
+
+Run biometric matching and verification in MPC - no plaintext biometric data leaves the user's
+device or passes through a single party.
+
+[Learn more →](/docs/identity-solutions/biometrics/introduction)
+
+</div>
+
+</div>

docs/identity-solutions/passport-identification/introduction.mdx

@@ -0,0 +1,28 @@
+---
+title: Threshold Passport Identification
+description: Match passport attributes without exposing document data
+---
+
+# Threshold Passport Identification
+
+Match passports or any identification document across parties without revealing the underlying document data.
+Built on the same MPC network TACEO co-architected for zkPassport.
+
+## The Problem
+
+Passports are the standard identity document in the physical world, making them a natural
+anchor for digital identity systems as well. But operating on passport data digitally requires
+careful handling: the underlying attributes are sensitive, tied to a real person, and cannot
+be rotated if compromised.
+
+A common mitigation is to hash the passport data before any comparison, so the raw document
+is never transmitted. This limits casual observers - but not the issuers. Passport-issuing
+authorities might hold the original data and can compute the same hashes, making users traceable to
+any party that issued their document.
+
+## The Solution
+
+TACEO:OPRF computes a nullifier over the passport hash using a threshold of independent MPC
+nodes. The resulting nullifier is deterministic - it uniquely identifies the user - but no
+single party, including TACEO or the document issuer, can compute it unilaterally. Knowledge
+of the passport's pre-image is no longer sufficient to derive or link the identifier.

docs/index.mdx

@@ -18,15 +18,17 @@ We're best known for our identity work: TACEO Network is a privacy backbone for
 global-scale identity systems, with services used by **World** and **zkPassport**. We're now bringing
 the same stack to onchain finance through **Merces**.
 
-## Build private payments on the chain you already use
+## TACEO Solutions
 
-<div className="service-card-success" style={{padding: '1.5rem 1.8rem', marginTop: '2rem'}}>
+<div style={{display: 'grid', gridTemplateColumns: 'repeat(auto-fit, minmax(320px, 1fr))', gap: '2rem', marginTop: '2rem'}}>
+
+<div className="service-card-success" style={{padding: '1.5rem 1.8rem'}}>
 
 ### **Finance Solutions**
 
 Private payments on the EVM chains you already use, built on Merces. Merces wraps ERC-20s like USDC into private balances, with compliance primitives at the protocol layer.
 
-**Live on Arc, Base, and Plasma testnets.** ~5M demo transactions, ~300 TPS, sub-cent gas on L2. Mainnet deployment in progress. The MPC protocol underneath is the same one TACEO co-architected for World's iris-code system, in production at global scale.
+**Live on Arc, Base, and Plasma testnets.** ~5M demo transactions, ~300 TPS, sub-cent gas on L2. Mainnet deployment in progress.
 
 **Looking for design partners.** Stablecoin issuers, fintechs, and payment infrastructure teams shipping private rails to production. Talk to us.
 
@@ -39,6 +41,27 @@ Private payments on the EVM chains you already use, built on Merces. Merces wrap
 
 </div>
 
+<div className="service-card-primary" style={{padding: '1.5rem 1.8rem'}}>
+
+### **Identity Solutions**
+
+Privacy-preserving identity at global scale. TACEO:OPRF is in production for **World** and **zkPassport** - the same MPC backbone that powers iris-code uniqueness and private credential matching is available for your identity system.
+
+**In production.** Distributed nullifiers, threshold passport identification, and confidential biometrics, backed by a threshold MPC network with no single point of failure.
+
+**Looking for design partners.** Identity protocol teams and credential issuers building privacy-first systems. Talk to us.
+
+{/* prettier-ignore */}
+<div className="button-row" style={{marginTop: '1.25rem', display: 'flex', flexWrap: 'wrap', alignItems: 'center', gap: '1rem'}}>
+  <Link className="button button--primary get-in-touch-btn" to="/docs/identity-solutions/overview">Read Identity Solutions</Link>
+  <Link className="button button--outline button--primary get-in-touch-btn" to="/docs/identity-solutions/nullifiers/getting-started/quickstart">Try the Quickstart</Link>
+  <Link className="button button--outline button--primary get-in-touch-btn" to="mailto:hello@taceo.io?subject=Identity%20Solutions%20design%20partner">Become a Design Partner</Link>
+</div>
+
+</div>
+
+</div>
+
 ## Other paths
 
 <div style={{display: 'grid', gridTemplateColumns: 'repeat(auto-fit, minmax(280px, 1fr))', gap: '2rem', marginTop: '2rem'}}>
@@ -104,7 +127,7 @@ coSNARK-based systems locally. Distinct from TACEO's managed services.
 ## Where TACEO is today
 
 - **Finance Solutions.** Merces is live on Arc, Base, and Plasma testnets with ~5M demo transactions, ~300 TPS, and single-digit-cents gas on L2. Mainnet deployment in progress.
-- **Privacy Services.** TACEO:OPRF and TACEO:Proof are in production for partners including World and zkPassport.
+- **Privacy Services.** TACEO:OPRF and TACEO:Proof are in production for partners including World and zkPassport. TACEO:OMap is deployed and onboarding first applications.
 - **TACEO Network.** The MPC infrastructure underpinning all of the above is built on the same foundation TACEO co-architected for World's iris-code system, in production at global scale.
 
 ## Learning Resources

docs/services/overview.mdx

@@ -65,39 +65,41 @@ _Private Proof Delegation_
 
 </div>
 
-</div>
+<div className="service-card-primary">
 
-## Coming Soon
+### **TACEO\:Match**
 
-<div style={{display: 'grid', gridTemplateColumns: 'repeat(auto-fit, minmax(300px, 1fr))', gap: '2rem', marginTop: '2rem'}}>
+_Distributed Biometric Matching_
 
-<div className="service-card-muted">
+**Use when you need:**
 
-### **TACEO\:OMap**
+- Population-scale uniqueness checks without centralizing templates
+- Cross-organization deduplication without sharing biometric databases
+- Anonymous identity verification - prove a match without revealing which identity
+- Sybil resistance backed by irrevocable biometric uniqueness
 
-_Private Reads & Writes_
+**Perfect for:**
 
-**Deployed, onboarding first applications**
+- Proof-of-uniqueness systems and anonymous credential issuance
+- Cross-border or cross-org fraud detection and deduplication
+- Privacy-preserving KYC and biometric verification
+- Any workload where biometric templates cannot be centralized
 
-Private data structures and confidential shared state management across multiple parties, with verifiable state updates. (currently onboarding initial applications).
+{/* prettier-ignore */}
+<Link className="button button--primary get-in-touch-btn" to="/docs/taceo-match/overview" style={{ marginTop: "1rem", width: "100%" }}>Learn More</Link>
 
 </div>
 
-<div style={{
-  padding: '2rem',
-  border: '1px solid var(--ifm-color-emphasis-400)',
-  borderRadius: '12px', 
-  backgroundColor: 'var(--ifm-color-emphasis-100)',
-  opacity: '0.8'
-}}>
+<div className="service-card-muted">
 
-### **TACEO\:Match**
+### **TACEO\:OMap** <span style={{fontSize: '0.75rem', fontWeight: 600, textTransform: 'uppercase', letterSpacing: '0.05em', opacity: 0.6}}>Coming Soon</span>
 
-_Distributed Biometric Uniqueness_
+_Private Reads & Writes_
 
-**In active integration**
+Private data structures and confidential shared state management across multiple parties, with verifiable state updates.
 
-Privacy-preserving uniqueness matching and verification without requiring a single party to hold sensitive data such as biometric templates.
+{/* prettier-ignore */}
+<Link className="button button--secondary get-in-touch-btn" to="/docs/taceo-omap/overview" style={{ marginTop: "1rem", width: "100%" }}>Learn More</Link>
 
 </div>
 

docs/taceo-match/concepts.mdx

@@ -0,0 +1,43 @@
+# Concepts
+
+## What is a Biometric Template?
+
+A biometric template is a compact mathematical representation of a biometric measurement. An iris code, for example, might encode the texture pattern of an iris as a bit vector of 11k bits. The actual bit length depends on the feature extraction, whether it is iris, face or palm scans. All share that they are fixed-length vectors designed to make comparison cheap and reliable.
+
+The challenge is that these vectors are **sensitive and irrevocable**. Unlike a password hash, a leaked biometric template cannot be rotated. Any system that stores or transmits raw templates creates a permanent liability.
+
+## Secret Sharing
+
+Secret sharing splits a value into $n$ shares such that any subset of size $< t$ reveals nothing about the original value, while any subset of size $\geq t$ can reconstruct it. In TACEO:Match, each enrolled template is split into shares distributed across independent MPC nodes on the TACEO Network. No node holds a full template.
+
+For a deeper treatment of MPC and the secret-sharing primitives TACEO uses, see the [MPC Resources](/docs/resources/mpc) page.
+
+## The Matching Function
+
+Biometric matching reduces to computing a distance metric between two templates and checking whether it falls below a threshold:
+
+```
+match = distance(probe, enrolled) < τ
+```
+
+For iris codes, this is **Hamming distance** - the fraction of bit positions that differ. Is the Hamming distance below a certain threshold $τ$ we can deduce that two scans belong to the same person.
+
+TACEO:Match evaluates this distance function directly on the secret shares of the enrolled template, without reconstructing the template at any node. The same approach extends to other distance-based biometric representations (e.g. cosine similarity for face embeddings) by implementing the corresponding comparison circuit.
+
+## Architecture
+
+Three independent MPC nodes execute the matching protocol and jointly hold a **secret-shared database** of all enrolled templates. Reconstruction requires at least $t$ shares - no node, and no coalition smaller than $t$, can read the stored data.
+
+A request originates at a sensor: a mobile device or dedicated hardware such as an orb or palm scanner. The sensor performs feature extraction, secret-shares the resulting template, and encrypts each share with the corresponding MPC node's public key, protecting the shares in transit. The choice of sensor does not change the architecture.
+
+Each MPC node decrypts its share and participates in the match protocol against the database. The protocol is parameterised by the distance function - for example, **Hamming distance** for iris codes (see [The Matching Function](#the-matching-function)). Only the final verdict is revealed: match or no match.
+
+<img src="/img/taceo_match.svg" alt="TACEO:Match architecture" width="100%" />
+
+An **orchestration server** may optionally relay requests between the sensor and the MPC nodes. It only ever observes encrypted shares, so user confidentiality is preserved end-to-end.
+
+## Composition with Nullifiers
+
+TACEO:Match and [Distributed Nullifiers](/docs/identity-solutions/nullifiers/introduction) are complementary primitives built on the same threshold MPC stack. Nullifiers derive a deterministic, unlinkable identifier from a secret input via OPRF; Match verifies that a biometric probe corresponds to an enrolled identity via MPC matching.
+
+A common composition: use Match to verify biometric uniqueness, then issue a nullifier tied to the verified identity. The user gets both sybil resistance (from Match) and unlinkability across interactions (from the nullifier).