TSP-2 — Card Standard

The maintained executable protocol is PLUMB v2. The v1 layouts below are historical design references and are incompatible with v2 witnesses.

PLUMB implementation for unique assets. See PLUMB for the shared token framework.

Conservation law: owner_count(id) = 1.

See the Gold Standard for design rationale and skill architecture.

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What Differs from TSP-1

1. Leaf represents an asset (unique item), not an account balance
2. Invariant: uniqueness, not divisible supply
3. No divisible arithmetic — no balance, no range checks, no splitting
4. Per-asset state — metadata, royalty, creator, flags live in the leaf
5. Creator immutability — creator_id is set at mint and can never change
6. Flag-gated operations — transferable, burnable, updatable bits control which PLUMB operations are allowed per asset

Operations are still Pay, Lock, Update, Mint, Burn. What changes is what the circuit enforces inside each.

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Asset Leaf — 10 field elements

leaf = hash(asset_id, owner_id, nonce, auth_hash, lock_until,
            collection_id, metadata_hash, royalty_bps, creator_id, flags)

Field	Type	Description
asset_id	Field	Globally unique asset identifier
owner_id	Field	Current owner (account_id hash)
nonce	Field	Monotonic counter
auth_hash	Field	Hash of owner's authorization secret
lock_until	Field	Timestamp lock (0 = unlocked)
collection_id	Field	Collection membership (0 = standalone)
metadata_hash	Field	Hash of item metadata
royalty_bps	Field	Royalty basis points (0-10000)
creator_id	Field	Original creator (immutable after mint)
flags	Field	Bitfield controlling allowed operations

First 5 fields occupy the same positions as TSP-1. Last 5 — reserved zeros in TSP-1 — carry per-asset state in TSP-2.

Flags Bitfield

Bit	Name	When set	When clear
0	TRANSFERABLE	Pay (transfer) allowed	Pay rejected
1	BURNABLE	Burn allowed	Burn rejected
2	UPDATABLE	Metadata update allowed	Metadata frozen forever
3	LOCKABLE	Lock (time-lock) allowed	Lock rejected
4	MINTABLE	Re-mint into collection allowed	Collection closed

Flags are set at mint time and cannot be changed after creation. A soulbound credential: flags = 0. A game item: flags = 31 (all operations). A standard collectible: flags = 11 (transferable + burnable + lockable).

Collection Binding

When collection_id != 0, the asset belongs to a collection identified by its config hash. Collection membership is immutable after mint.

Creator Immutability

creator_id is set at mint and preserved by every subsequent operation. Provides an unforgeable provenance chain. The Royalties skill reads royalty_bps from the leaf and royalty_receiver from collection metadata.

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Token Config — 10 field elements

See PLUMB Config.

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Collection Metadata — 10 field elements

metadata = hash(name_hash, description_hash, image_hash, site_hash, custom_hash,
                max_supply, royalty_receiver, 0, 0, 0)

Field	Type	Description
name_hash	Field	Hash of collection name
description_hash	Field	Hash of collection description
image_hash	Field	Hash of collection image/avatar
site_hash	Field	Hash of collection website URL
custom_hash	Field	Hash of application-specific data
max_supply	Field	Maximum number of assets (0 = unlimited)
royalty_receiver	Field	Account that receives royalties on transfers
reserved	Field x3	Extension space

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Merkle Tree

See PLUMB Merkle Tree.

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Global Public State

Field	Type	Description
state_root	Digest	Merkle root of all assets
asset_count	Field	Total number of assets in tree
config_hash	Digest	Token configuration commitment
metadata_hash	Digest	Collection metadata commitment
current_time	Field	Block timestamp for time-lock checks

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Operations

All operations follow the PLUMB proof envelope.

Op 0: Pay (Transfer Ownership)

Constraints:

1. Config verified, pay_auth and pay_hook extracted
2. Asset leaf verifies against old_root
3. hash(secret) == leaf.auth_hash
4. If pay_auth != 0, dual auth required
5. current_time >= leaf.lock_until
6. leaf.flags & TRANSFERABLE
7. collection_id, creator_id, royalty_bps, metadata_hash, flags unchanged
8. New leaf: owner_id = new_owner, auth_hash = new_auth, nonce += 1
9. New leaf produces new_root
10. Nullifier emitted: hash(asset_id, nonce)

Op 1: Lock (Time-Lock Asset)

Constraints:

1. Config verified, lock_auth and lock_hook extracted
2. Owner auth required
3. If lock_auth != 0, dual auth required
4. leaf.flags & LOCKABLE
5. lock_until_time >= leaf.lock_until (extend only)
6. All immutable fields unchanged
7. Leaf: lock_until = lock_until_time, nonce += 1

Op 2: Update (Config or Metadata)

Config update:

1. old_root == new_root (state unchanged)
2. Admin auth, admin_auth != 0
3. New config fields hash to new_config

Metadata update:

1. Owner auth required
2. flags & UPDATABLE
3. Only metadata_hash changes
4. nonce += 1

Op 3: Mint (Originate)

Constraints:

1. Config verified, mint_auth and mint_hook extracted
2. mint_auth != 0 (minting enabled)
3. Mint authorization verified
4. asset_id not in tree (non-membership proof)
5. creator_id = minter_id (immutable forever)
6. collection_id, flags, royalty_bps set (immutable after mint)
7. flags & MINTABLE
8. nonce = 0, lock_until = 0
9. New leaf produces new_root
10. new_asset_count == old_asset_count + 1
11. If max_supply != 0: new_asset_count <= max_supply

Op 4: Burn (Release)

Constraints:

1. Config verified, burn_auth and burn_hook extracted
2. Owner auth required
3. If burn_auth != 0, dual auth required
4. current_time >= leaf.lock_until
5. leaf.flags & BURNABLE
6. Leaf removed (Merkle deletion)
7. new_asset_count == old_asset_count - 1
8. Nullifier emitted: hash(asset_id, nonce)

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Hooks

See PLUMB Hook System. All 5 hook slots are available. See Skill Reference for standard hook programs.

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Security Properties

All PLUMB framework security properties apply.

Additional TSP-2 properties:

1. Uniqueness — non-membership proof at mint, exactly one leaf per asset_id
2. Creator immutability — creator_id set at mint, preserved by all operations
3. Flag enforcement — operations rejected if the corresponding flag bit is clear
4. Supply cap — if max_supply != 0, minting rejected when asset_count >= max_supply
5. Immutable fields — collection_id, creator_id, royalty_bps, flags never change after mint