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<img src="https://www.Blockchaincommons.com/images/bcc-card.jpg" width=1024>
<font size="5">Blockchain Commons #GordianClubs
2025-10-01</font>
---
## <img src="https://i.imgur.com/QyDl5nK.png" width="192" height="192"></br> What is Blockchain Commons?
<font size=6>
* We are a community interested in self-sovereign control of digital assets and identity
* We bring together stakeholders to collaboratively develop interoperable infrastructure
* We design decentralized solutions where everyone wins
* We are a neutral "not-for-profit" that enables people to control their own digital destiny
</font>
---
Thank you to our Sponsors!
<img src="https://hackmd.io/_uploads/HkL6BW5hge.png" style="border: 1px white solid;">
Become a sponsor!
Mail us at team@blockchaincommons.com
---
## <img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>Last Meeting
### FROST Signing on the Command-Line
#### August 2025
<font size=6>
* Demo of FROST signing of Bitcoin transactions
* with BDK & ZF FROST Tools
* See https://developer.blockchaincommons.com/meetings/
</font>
---
## <img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>Today's Topics
<font size=6>
- Project Xanadu: Before Its Time
- Gordian Clubs: An Introduction
- Gordian Clubs: A Demo
</font>
---
<img src="https://hackmd.io/_uploads/BkV3kxMhxe.png" width=75>
## Project Xanadu
<font color="yellow">
"In <font color="coral">Xanadu</font> did Kubla Khan<br>
A stately pleasure-dome decree:<br>
Where Alph, the sacred river, ran<br>
Through caverns measureless to man<br>
Down to a sunless sea."
</font>
—Samuel Taylor Coleridge
---
<img src="https://hackmd.io/_uploads/BkV3kxMhxe.png" width=75>
### Project Xanadu Background
* First Hypertext Project
* "digital repository scheme for world-wide electronic publishing"
* 1960, named Xanadu in 1966
* Very active in late 1970s
* At Autodesk in 1980s
* I became involved in early 1990s
* Visionary: Ted Nelson
* Other Luminaries: Roger Gregory, Mark S. Miller & Stuart Greene
---
<img src="https://hackmd.io/_uploads/BkV3kxMhxe.png" width=75>
### Project Xanadu vs WWW
* Developed before the internet, Xanadu was in many ways superior to the World Wide Web that followed it:
* Two-Way Links
* Uniquely Identified Users
* Uniquely Identified Documents
* Dynamically Changing Storage
* Micropayments
---
<img src="https://hackmd.io/_uploads/BkV3kxMhxe.png" width=75>
### The Xanadu Club System
<font size=5>
* **I was particularly inspired by the Xanadu Club System:**
* **Public-by-Default**: The root was a public club, openness was default, privacy was a partition
* **Person as Club of One**: No difference between people and groups
* **Clubs as Members**: Groups could hold rights and be members of other groups
* **Recursive Clubs**: Read Clubs and Write Clubs themselves have Read & Write Clubs
* **“Locksmith” options**: Clubs could grant access through different kinds of locksmiths for different purposes
</font>
---
<img src="https://hackmd.io/_uploads/BkV3kxMhxe.png" width=75>
### Why This Was Revolutionary
<font size=5>
* **Natural hierarchies** without central administration
* **Flexible governance** through nested permission structures
* **Scriptable access control** using early smart contracts for permissions
* **Unified identity model** with people and groups treated identically
* _**Modeled how human trust hierarchies actually work**_
</font>
---
<img src="https://hackmd.io/_uploads/Symx5kfnll.png" width=80%>
---
<img src="https://hackmd.io/_uploads/BkV3kxMhxe.png" width=75>

---
<img src="https://hackmd.io/_uploads/BkV3kxMhxe.png" width=75><br/>
## The Problem with Xanadu Clubs:
## ~~“Mother may I?”~~ Administrative Fiat
**Not**
## **“I can prove I belong.”** Mathematical Proof
---
### <img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/> Gordian Clubs: 32 Years in the Making
* **1993**: I proposed cryptographic clubs for Xanadu
* But: ⚠️ "RSA too slow; RSA export-restricted; good code doesn't exist"
* **2001**: ⚠️ "Patents too restrictive; patents too expensive"
* **2014**: ⚠️ "Schnorr aggregation not safe"
* **2025**: Technology finally caught up to the vision
* **Gordian Clubs**: Schnorr signatures, FROST, Gordian Envelope, XIDs
* **Result**: Pure mathematical objects that encode permissions in their structure
---
### Gordian Club Vision: Recursive Cryptographic Capabilities
<font size=5>
**Mathematical Delegation**
* **Clubs granting capabilities to other clubs**
* No administrative intermediaries
* Pure cryptographic authorization chains
* **Recursive permission structures**
* Club A grants read access to Club B
* Club B can delegate subsets to Club C
* All enforced by mathematics, not code
* **Complete Xanadu realization**
* Ted Nelson's hypertext with cryptographic enforcement
* "You are what you can prove you can access"
**Rather than being simple documents, Clubs are autonomous objects.**
</font>
---
### Gordian Clubs: Autonmous Access
<font size=5>
* You receive an `Edition` produced by a Gordian Club. The content of the `Edition` is encrypted and signed.
* Transport agnostic: Internet; P2P; TOR; NFC; satellite; sneaker-net
* You apply your cryptographic proofs to obtain READ privileges to the `Edition` content
* The decrypted `Edition` content may reveal nested `Editions` from the same or other Clubs, which you may or may not have access to.
* You update an `Edition` by authoring new `Edition`s in particular clubs that must be accepted as authoritative due to your cryptographic proofs.
_**No Server, No Database, No Phoning Home!**_
---
### Access Control: Cryptographic OCaps
<font size=5>
_Meeting these goals required the replacement of traditional (Xanadu) OCaps with cryptographic OCaps._
**Traditional Ocaps**: Software enforces capability delegation
**Cryptographic Ocaps**: Mathematics enforces capability delegation
* **How Gordian Clubs Bridge This:**
* **Permits** = cryptographic capabilities for read access
* **Schnorr Signatures** = foundation of composable smart signature protocols
* **Adaptor signatures** = aka _“Scriptless Scripts”_ - conditional authorization protocols
* **FROST thresholds** = group decision capabilities
* **For the Ocap Community:**
* Same principles, cryptographic enforcement instead of code
* **Capabilities become mathematical objects**
* No confused deputy problem - math doesn't lie
</font>
---
### The Schnorr Foundation: Mathematical Elegance
<font size=5>
_Many of the capabilities that we need are supported through Schnorr signatures._
* **The Key Property: Signature Indistinguishability**
* Single-party signature = Multi-party signature (same verification)
* Simple workflow = Complex workflow (same mathematical structure)
* **Mathematical linearity** enables seamless composition
* Why This is Extraordinary
* Start with basic cryptographic objects
* Evolve to sophisticated multi-party protocols
* **External systems never need to change**
* Same verification logic, infinite internal complexity
</font>
---
### The Schnorr Revolution: True Composability
* **Schnorr's Super Power: Composable Cryptographic Primitives**
* Layer complexity without breaking compatibility
* All primitives use the same mathematical foundation
* All primitives produce indistinguishable signatures
* All primitives can be combined and layered
* **Cryptographic LEGO blocks** that actually fit together
---
### Cryptographic LEGO Blocks: The Schnorr Ecosystem
<font size=5>
* **Initial Schnorr LEGO Blocks in Gordian Clubs:**
* #1: **Adaptor Signatures** → Scriptless Scripts (conditional logic)
* #2: **FROST** → Threshold operations (group decisions)
* **Future LEGO Blocks:**
* **MuSig2** → Key aggregation
* **Blind Signatures** → Privacy
* **Predicate Logic** → Complex conditional authorization
* _**More!**_
* We can build complex systems from simple, interoperable parts!
</font>
---
### LEGO Block #1: Scriptless Scripts
<font size=5>
* **Adaptor Signatures: Conditional Logic in Pure Math**
* _“If condition X, then unlock Y”_ → Mathematical proof
* _“Atomic operations across systems”_ → Single signature verification
* _“Complex multi-party workflows”_ → Elegant cryptographic composition
* **The Developer Opportunity: Infrastructure-Free Logic**
* Embed conditions directly into Schnorr signatures
* Chain operations without external coordination
* _**Build workflows that are pure mathematics**_
* **Use Cases:**
* Conditional access, delegation, attenuation, atomic swaps
* Cross-system coordination, delegation chains
* _**Any logic expressible in math**_ - no servers required
</font>
---
### Limitations of Schnorr Adaptor Signatures
<font size=5>
* **Limited to signature mathematics** - bounded by what elliptic curves can express
* **No loops or iteration** - mathematics is finite, not computational
* **No conditional branching on external events** - logic must be deterministic
* **No mutable state** - each operation creates new mathematical objects
* **These "limitations" offer freedom:**
* Freedom from platform lock-in, censorship, surveillance
* _**Mathematical certainty replacing administrative whim**_
</font>
---
### LEGO Block #2: FROST Threshold Operations
<font size=5>
* **FROST: Flexible Round-Optimized Schnorr Threshold**
* **M-of-N signatures** that look like single signatures
* **Privacy-preserving** - can't tell who participated
* **Same verification logic** as single-party signatures
* **Two Core Applications:**
* **Threshold Signing** → Group authorization for updates
* **Group-Managed Provenance** → Shared custody of version history
* **Developer Power:**
* Start with single-party authorization
* **Seamlessly upgrade** to group governance
* External systems never know the difference
</font>
---
### FROST in Practice: Group Governance Made Simple
<font size=5>
* **Signing Ceremonies:**
* **Coordinate off-chain** → Generate signatures
* **Single signature result** → Same as individual signing
* **No coordinator required** → Can be peer-to-peer protocol
* **Provenance Chain Management:**
* **Shared custody** of version history
* **No single point of failure** for critical records
* **Deterministic advancement** without central authority
* **Use Cases:**
* **Organizational governance** without servers
* **Community decisions** with cryptographic proof
* **Succession planning** built into the mathematics
</font>
---
### Limitations of FROST Threshold Operations
<font size=5>
* **Coordination complexity** - requires secure multi-party communication
* **Network availability** - signing ceremonies need participant connectivity
* **Key management burden** - key distributed across multiple parties
* **No atomic composition** - can't combine with other protocols mid-ceremony
* **These “limitations” offer freedom:**
* Freedom from single points of failure and control
* _**Democratic governance through cryptographic consensus**_
</font>
---
### Future LEGO Blocks: The Expanding Toolkit
<font size=5>
* **Each new block** builds on the same Schnorr foundation
* **Infinite composability** from finite primitives
* **Next (2026?):**
* **MuSig2** → Key aggregation with accountability
* **Additional object capabilities** such as attenuation
* **Blind Signatures** → Privacy-preserving authorization
* **Predicate Logic** → Complex conditional authorization
* **For Developers:**
* **Build on stable foundation** being adopted by Bitcoin and other projects
* _**Mathematical certainty in an uncertain world!**_
</font>
---
## From Schnorr Foundation to Gordian Implementation
<font size=5>
**Now you understand our goals & general design. Here's how we built them:**
* **Selected our data structures**: 🔗 dCBOR + 📦 Gordian Envelope
* **Chose our Schnorr LEGO blocks**: 🤝 FROST + 🖋️ adaptor signatures
* **Added identity layer**: 🅧 XIDs for decentralized member management
* **Secured our data**: 🎫 Envelope permits
* **Created coordination protocols**: 🅟 Provenance Marks & 🔒 GSTP
</font>
---
### Gordian Stack: Data Foundations
<font size=5>
**Here are our specific technology choices for creating Gordian Clubs within the Gordian Stack:**
* **🔗 dCBOR (Deterministic CBOR)**
* Binary encoding ensures that identical semantics produces identical bytes
* Foundation for cryptographic verification and content addressing
* **📦 Gordian Envelope (Smart Document Architecture)**
* A hash-tree of hash-trees
* Subject-predicate-object semantic structure
* Selective disclosure through *elision* or *encryption*
* Reveal only what's needed
* Radically recursive — everything is an Envelope
---
### Gordian Stack: Schnorr LEGO Blocks
<font size=5>
* **🤝 FROST (Flexible Round-Optimized Schnorr Threshold)**
* M-of-N threshold signatures indistinguishable from single signatures for **online** group signing
* Privacy-preserving: Can't tell which specific members participated
* Enables group decision-making without revealing individual votes
* **🖋️ Adapter Signatures**
* Conditions embedded in signatures
</font>
---
### Gordian Stack: Identity & Access Control
<font size=5>
* **🅧 XIDs (eXtensible IDentifiers)**
* 32-byte cryptographic identifiers derived from keys (🅧 7e1e25d7...)
* Resolve to XID Documents with communication keys, endpoints, permissions, etc.
* Support key rotation while maintaining stable identity
* **🎫 Permits: Multiple Ways to Access Same Content**
* **XID permits** - Identity-based access with key rotation support
* **Public key permits** - Direct cryptographic access to specific keys
* **SSKR threshold shares** (2-of-3, 3-of-5, etc.) for **offline** key reconstruction
* **Password permits** for simple access scenarios
* Each permit type decrypts to the same base symmetric key
</font>
---
### Gordian Stack: Coordination & Verification
<font size=5>
* **🅟 Provenance Marks: Cryptographic Edition Ordering**
* Sequential, tamper-evident chains of document versions
* Each mark cryptographically links to content digest and previous mark
* **Genesis Mark (#0)** → **Mark #1** → **Mark #2** → continuous chain
* Enable write access validation and update authorization
* Prevent backdating or unauthorized modification
* Human-readable names (🅟 KNOB BETA AQUA NOON) for easy verification
* **🔒 GSTP: Secure Multi-Party Coordination**
* Transport-agnostic protocol (works over Bluetooth, QR, NFC)
* Encrypted message exchange with state preservation
* Enables secure coordination without infrastructure
</font>
---
### How Gordian Clubs Use These Technologies
<font size=5>
* **When You Create a Club:**
* **XID** identifies the club entity (publisher) across updates
* Content encrypted and stored in **Gordian Envelope** using **dCBOR**
* Multiple **permits** allow different access methods (keys, passwords, shares)
* **When Members Make Decisions:**
* **FROST** threshold signatures authorize updates without revealing who voted
* **Provenance marks** create tamper-evident history of all changes
* **GSTP** coordinates secure communication between members
* **The Result: Autonomous Cryptographic Objects**
* No servers, no databases, no central authority
* Mathematical proofs replace administrative control
* Unstoppable, private, censorship-resistant collaboration
</font>
---
### The Structure of a Gordian Club
<font size=5>
_A Gordian Club is a layered onion, with some information widely readable and some not:_
1. **Club Envelope:** dCBOR-encoded structure containing everything
2. **Public Metadata:** Visible information (club ID, version, etc.)
3. **Encrypted Payload:** The actual club content and member data
4. **Access Layer:** Collection of permits for different entry methods
5. **Governance Layer:** FROST signatures and provenance chain
**Result:** Self-contained cryptographic object requiring no external infrastructure
</font>
---
### Read vs. Write Access Model
<font size=5>
**Two Distinct Permission Types:**
* **🔍 Read Access**
* Decrypt and view current club content
* Multiple permit types provide different access methods
* One-time or ongoing access depending on permit type
* **✏️ Write Access**
* Create new editions with updated content or membership
* Requires FROST threshold signatures from existing write group
* Provenance marks cryptographically ensure ordering
**This separation enables flexible governance while maintaining security**
</font>
---
### The Power of Autonomy
Autonomous Cryptographic Objects enable ...
* **Unblockable Access**
* No server can be taken down to block access
* **Perfect Privacy**
* No logs, no tracking, no surveillance possible
* **Disaster Resilience**
* Works during internet outages or infrastructure failures
* **Censorship Resistance**
* No authority can revoke mathematical proofs
* **True Ownership**
* Control rests with keyholders, not platform operators
---
### Platform Independence
* Coordination that can't be algorithmically suppressed
* Communities that can't be deplatformed
* _**Mathematical certainty replacing platform dependency**_
---
### Use Cases
* **When Infrastructure Can't Be Trusted:**
* Dissidents organizing without surveillance
* Long-term archival that outlives companies
* Emergency coordination during outages
* _**Mathematical proofs endure when servers don't**_
---
### What You'll See in the Demo
<font size=5>
**Wolf will demonstrate the proof-of-concept implementation:**
1. **🅧 Identity Setup** - Creating XIDs for Publisher, Alice, and Bob
2. **📝 Genesis Edition** - Encrypting "Welcome to Gordian Club!" with multiple permits
3. **🔓 Access Methods** - Alice decrypts with XID permit, same content via SSKR shares
4. **🅟 Edition Updates** - Publisher creates "Second Edition" with provenance continuity
5. **✅ Verification** - Proving authenticity and sequence without servers
**Watch for:** Self-contained data artifacts working without any infrastructure
</font>
---
### SSKR Threshold Reconstruction in Action
<font size=5>
**Demo will show 2-of-3 threshold shares:**
* **Publisher creates** 3 SSKR shares when sealing content
* **Any 2 shares** can reconstruct the decryption key
* **Same plaintext** emerges from SSKR as from XID permits
* **Offline capability** - no coordination needed between shareholders
**Key insight:** Multiple paths to same content, different security models
</font>
---
### Edition Structure You'll See
<font size=5>
**Encrypted envelope contains:**
```txt
{
ENCRYPTED [
'isA': "Edition"
'hasRecipient': SealedMessage // Alice's XID permit
'hasRecipient': SealedMessage // Bob's pubkey permit
"club": XID(8f5980be)
'hasRecipient': SealedMessage // Proves the publishing order of this Edition
'provenance': ProvenanceMark(c14fafa0)
]
} [
'signed': Signature // Publisher's cryptographic seal
]
```
**Plus separate SSKR share envelopes for threshold access**
</font>
---
### Verification Steps You'll See
<font size=5>
**Wolf will demonstrate cryptographic validation:**
* **`clubs edition verify`** - Proves edition authenticity and signature validity
* **`clubs edition sequence`** - Validates provenance chain continuity
* **Content decryption** - Shows multiple permit types accessing same data
* **Provenance progression** - Genesis mark → Mark #1 with content linking
***No servers consulted, no external validation needed***
</font>
---
<img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>
## `clubs-cli-rust` Demo
*You now have the foundation to understand what you'll see next…*
**Wolf will demonstrate these concepts working together in a real implementation**
---
<img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>
### Two Rust Repositories
<font size=5>
**What Wolf just demonstrated is built on:**
* **📚 `clubs-rust`** - Core cryptographic library
* Edition creation, FROST signatures, permit handling
* GitHub: https://github.com/BlockchainCommons/clubs-rust
* **⚡ `clubs-cli-rust`** - Command-line interface (what you saw in action)
* Complete demo workflow in `demo-log.md`
* GitHub: https://github.com/BlockchainCommons/clubs-cli-rust
</font>
---
### <img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>🔧 Getting Started
* To install the tools:
* `cargo install envelope-cli provenance-cli clubs-cli`
* Full walkthrough:
* https://github.com/BlockchainCommons/clubs-cli-rust/blob/master/demo-log.md
---
<img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>
### Future Work (I) - FROST Editions
<font size=5>
* **Using FROST for Editions:**
* Create the symmetric key to encrypt `Edition` content.
* Create the next provenance mark in a chain without a secret seed.
* Sign the `Edition` Gordian Envelope
**Status:** proof of concept code working for FROST groups to collaboratively conduct FROST rounds for editions.
---
<img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>
### Future Work (II) - FROST Workflows
<font size=5>
* **FROST Publish:** integrate these pieces into a workflow for FROST groups to publish `Editions` indistinguishable from those produced by a single-entity publisher.
* **FROST Coordinator:** create a server, `hubert`, which is a "dumb" message passing hub for GSTP messages.
* Allows encrypted message passing between participants without having any idea what the messages mean.
* Supports single-cast, multi-cast, and store-and-forward of GSTP messages.
* Simplifies the communication needed to conduct the FROST rounds needed to produce new `Editions`.
* Provides flexible infrastructure for the development of future protocols.
**Status:** We already have working libraries for FROST and GSTP, just need to integrate with code for Gordian Clubs.
</font>
---
<img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>
### Future Work (III) - Cryptographic Ocaps
<font size=5>
**What you saw:** Static permissions via permits and signatures
**What's possible:** Dynamic capabilities using adaptor signatures
* Delegate authority without sharing keys
* Attenuation (restricting permissions when delegating)
* Composition (chaining capabilities across systems)
**Status:** Research phase—novel cryptographic constructions requiring formal proofs
**We need cryptographers, engineers, and visionaries to build this together.**
</font>
---
### Ocap Delegation Without Key Sharing
* **Adaptor signatures enable a powerful pattern:**
* Alice can delegate her read or write authority to Bob without sharing keys and without creating a new edition.
* **"Naive" = Conceptually Sound, Needs Formal Security Analysis**
* Like naive Schnorr aggregation (which can leak keys → thus the MuSig2/MuSig-DN protocols), these examples demonstrate the core pattern but require cryptographic proofs before production use.
* **Here's how…:**
---
### Naive Read Delegation via Adaptor Signatures
<font size=5>
* **Goal:** Alice (with read access) delegates to Bob without sharing keys OR updating current edition
1. **Alice creates an incomplete signature**
- Generates random secret `t` and commits to it: `T = t·G`
- Encrypts symmetric key: `k_enc = k ⊕ hash(t, B, edition_id)`
- Creates adaptor signature hiding `t` that only Bob can complete
2. **Only Bob can complete it**
- Bob uses his private key `b` to complete the signature
- Completion reveals the secret `t` to Bob (and only Bob)
3. **Result: Delegated read authority**
- Bob can decrypt this edition using revealed `t`
- Computes: `k = k_enc ⊕ hash(t, B, edition_id)`
- No key sharing required
- Alice retains her original access
* **Key insight:** The incomplete signature hides a secret that unlocks decryption—a cryptographic "locked box" that only Bob's key can open.
</font>
---
### Naive Write Delegation via Adaptor Signatures
<font size=5>
* **Goal:** Alice (with write access) delegates to Bob without sharing keys OR updating current edition
1. **Alice creates an incomplete signature**
- Standard Schnorr: `s = r + H(m)·a`
- Adaptor version: `s' = r + tweak + H(m)·a`
- The "tweak" is locked to Bob's public key
2. **Only Bob can complete it**
- Bob uses his private key `b` to derive the tweak to produces a valid signature from Alice
- Proves both: Alice's authorization + Bob's identity
3. **Result: Delegated write authority**
- Bob can create a new edition
- Each shows Alice's valid signature
- No key sharing required
- Alice retains her original authority
* **Key insight:** The incomplete signature is a cryptographic "blank check" that only Bob can fill out, creating mathematical proof of delegation.
</font>
---
### Future Work (IV) - Vetting of FROST Provenance Mark VRF Cryptography
<font size=5>
* **The Problem**: When a FROST group publishes a new edition's 🅟 Provenance Mark, we need a signature that produces a unique, unpredictable symmetric key that everyone can verify came from the group.
* **Our Solution**: Use a VRF (Verifiable Random Function) where:
- The group shares a secret no individual knows
- Each document creates a unique mathematical challenge
- The group collaboratively solves it, producing an apparently random number that's:
- Unique to this group
- Publicly verifiable
- Unpredictable yet deterministic
* **Why It Matters**:
- Creates cryptographic proof of group consensus
- Forms an unbreakable chain of documents
- No individual can cheat or predict future keys
* **Analogy**: A combination lock where the group collectively knows the combination, but no individual does—each use produces a new, verifiable number only they could create.
</font>
---
### Future Work (IV) - Vetting of FROST Provenance Mark VRF Cryptography (continued)
<font size=5.5>
- **Ciphersuite**: ZCash `frost-secp256k1-tr` with secp256k1 curve
- **Group Setup**: $t$-of-$n$ threshold Schnorr with shared public key $X = x \cdot G$
- **VRF Message**: $m_j=\mathrm{H}(\verb|"PMVRF-secp256k1-v1"| \| X \| \text{chain_id} \| S_{j-1} \| j)$
- **Hash-to-Curve**: $H_j = \text{H2C}(m_j)$ using SSWU with domain separation
- **VRF Output**: $\Gamma_j = x \cdot H_j$ (computed via FROST threshold ceremony)
- **DLEQ Proof**: Chaum–Pedersen $\pi_j$ proving $\log_G(X) = \log_{H_j}(\Gamma_j)$
- Challenge: $e = \text{H}_2(X \| \Gamma_j \| A \| B \| \verb|"FROST-VRF-DLEQ-2025"|)$
- Response: $z = k + e \cdot x$
- **Key Derivation**: $\text{key}_j = \text{SHA256}(\verb|"PMKEY-v1"| \| \Gamma_j)[:\text{resolution}]$
- **Ratchet State**: $S_j = \text{SHA256}(\verb|"PMSTATE-v1"| \| S_{j-1} \| \text{expand}(\text{key}_j))$
- **Genesis**: $S_0 = \text{SHA256}(\verb|"PM-Genesis"|)$
- **Properties**: Deterministic, roster-invariant, publicly verifiable
</font>
---
### <img src="https://i.imgur.com/QyDl5nK.png" width=192 height="192"><br/>Get Involved with Gordian Clubs
* Everyone
* Let us know what your use cases are for this technology!
* Where practical problems can true autonomous data objects solve today?
* Cryptographers
* We have novel constructions that need cryptographic proofs!
* Engineers
* We would like peer review of our protocols and code.
* Companies
* We need partners interested in this tech!
* Patrons
* We need financial support!
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Christopher Allen (@ChristopherA)
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