BRICS Path

Review - BRICS Overview

Developing the following paths :

1 - The oracle network architecture for ecological impact valuation 2 - Zero-knowledge proof circuits for private credit verification 3 - The economic game theory of liquidity provision 4 - Smart contract security patterns for cross-chain atomic swaps

Four critical technical paths in depth, building on regenerative credit architecture.

Path 1: Oracle Network Architecture for Ecological Impact Valuation

The Challenge

Traditional oracles price financial assets. You need to price regenerative contributions - forest restoration, soil carbon sequestration, biodiversity enhancement, water quality improvement - and translate these into credit capacity.

Multi-Layered Oracle Architecture

// pallets/ecological-oracle/src/lib.rs

use frame_support::{
decl_module, decl_storage, decl_event, decl_error,
traits::{Get, Randomness},
};
use sp_std::prelude::*;
use sp_runtime::traits::{Hash, Zero};

/// Core ecological metrics that oracles must attest to
#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub struct EcologicalMetrics {
// Carbon metrics
pub carbon_sequestered_tonnes: u64,
pub carbon_verification_method: CarbonVerificationMethod,

// Biodiversity metrics
pub biodiversity_score: u32, // 0-1000
pub species_count: u32,
pub habitat_hectares: u64,

// Soil health
pub soil_organic_matter_percent: u32, // basis points
pub soil_carbon_ppm: u64,

// Water systems
pub water_quality_index: u32, // 0-100
pub watershed_area_hectares: u64,

// Social metrics
pub jobs_created: u32,
pub community_members_served: u64,

// Temporal
pub measurement_period_days: u32,
pub verification_timestamp: Timestamp,
}

#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub enum CarbonVerificationMethod {
RemoteSensing,
FieldMeasurement,
ModelEstimate,
ThirdPartyAudit,
}

/// Oracle data source with reputation staking
#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub struct OracleProvider<AccountId, Balance> {
pub provider_id: AccountId,
pub stake: Balance,
pub reputation_score: u64,
pub specialization: Vec<OracleSpecialization>,
pub data_submissions: u64,
pub disputes_lost: u64,
pub last_active: BlockNumber,
}

#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub enum OracleSpecialization {
CarbonAccounting,
BiodiversityAssessment,
SoilScience,
HydrologicalSystems,
RemoteSensing,
SocialImpact,
}

/// Ecological attestation from multiple oracles
#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub struct EcologicalAttestation<AccountId, Hash> {
pub attestation_id: Hash,
pub subject_account: AccountId,
pub project_id: ProjectId,
pub metrics: EcologicalMetrics,
pub oracle_provider: AccountId,
pub confidence_level: u8, // 0-100
pub supporting_data_ipfs: Vec<u8>, // IPFS CID
pub signature: Vec<u8>,
}

decl_storage! {
trait Store for Module<T: Config> as EcologicalOracle {
/// Registered oracle providers
OracleProviders get(fn oracle_provider): 
map hasher(blake2_128_concat) T::AccountId => 
Option<OracleProvider<T::AccountId, BalanceOf<T>>>;

/// Attestations by project
ProjectAttestations get(fn project_attestations):
double_map hasher(blake2_128_concat) ProjectId,
hasher(blake2_128_concat) T::Hash =>
Option<EcologicalAttestation<T::AccountId, T::Hash>>;

/// Aggregated consensus metrics
ConsensusMetrics get(fn consensus_metrics):
map hasher(blake2_128_concat) ProjectId =>
Option<EcologicalMetrics>;

/// Dispute resolution state
ActiveDisputes get(fn active_disputes):
map hasher(blake2_128_concat) T::Hash =>
Option<DisputeState<T::AccountId, BlockNumber>>;

/// Valuation coefficients (governance-adjustable)
ValuationCoefficients get(fn valuation_coefficients):
map hasher(blake2_128_concat) MetricType => u64;
}
}

decl_event!(
pub enum Event<T> where
AccountId = <T as frame_system::Config>::AccountId,
Hash = <T as frame_system::Config>::Hash,
{
/// Oracle registered [provider_id]
OracleRegistered(AccountId),

/// New attestation submitted [attestation_id, project_id, oracle]
AttestationSubmitted(Hash, ProjectId, AccountId),

/// Consensus reached [project_id, metrics_hash]
ConsensusReached(ProjectId, Hash),

/// Dispute opened [attestation_id, challenger]
DisputeOpened(Hash, AccountId),

/// Dispute resolved [attestation_id, outcome]
DisputeResolved(Hash, DisputeOutcome),
}
);

decl_error! {
pub enum Error for Module<T: Config> {
/// Oracle not registered
OracleNotRegistered,
/// Insufficient stake
InsufficientStake,
/// Project not found
ProjectNotFound,
/// Attestation already exists
AttestationExists,
/// Not enough attestations for consensus
InsufficientAttestations,
/// Dispute period expired
DisputePeriodExpired,
}
}

decl_module! {
pub struct Module<T: Config> for enum Call where origin: T::Origin {
type Error = Error<T>;
fn deposit_event() = default;

/// Register as an oracle provider with stake
#[weight = 10_000]
pub fn register_oracle(
origin,
stake: BalanceOf<T>,
specializations: Vec<OracleSpecialization>,
) -> DispatchResult {
let who = ensure_signed(origin)?;

// Ensure minimum stake
ensure!(
stake >= T::MinimumOracleStake::get(),
Error::<T>::InsufficientStake
);

// Lock stake
T::Currency::reserve(&who, stake)?;

// Create provider entry
let provider = OracleProvider {
provider_id: who.clone(),
stake,
reputation_score: T::InitialReputationScore::get(),
specialization: specializations,
data_submissions: 0,
disputes_lost: 0,
last_active: <frame_system::Pallet<T>>::block_number(),
};

OracleProviders::<T>::insert(&who, provider);
Self::deposit_event(RawEvent::OracleRegistered(who));

Ok(())
}

/// Submit ecological attestation for a project
#[weight = 50_000]
pub fn submit_attestation(
origin,
project_id: ProjectId,
metrics: EcologicalMetrics,
confidence_level: u8,
supporting_data_ipfs: Vec<u8>,
) -> DispatchResult {
let who = ensure_signed(origin)?;

// Verify oracle is registered
let mut provider = Self::oracle_provider(&who)
.ok_or(Error::<T>::OracleNotRegistered)?;

// Generate attestation ID
let attestation_id = T::Hashing::hash_of(&(
&project_id,
&who,
&metrics,
<frame_system::Pallet<T>>::block_number(),
));

// Create attestation
let attestation = EcologicalAttestation {
attestation_id: attestation_id.clone(),
subject_account: who.clone(),
project_id,
metrics: metrics.clone(),
oracle_provider: who.clone(),
confidence_level,
supporting_data_ipfs,
signature: vec![], // Would be actual signature
};

// Store attestation
ProjectAttestations::<T>::insert(
project_id,
attestation_id.clone(),
attestation,
);

// Update provider stats
provider.data_submissions += 1;
provider.last_active = <frame_system::Pallet<T>>::block_number();
OracleProviders::<T>::insert(&who, provider);

Self::deposit_event(RawEvent::AttestationSubmitted(
attestation_id,
project_id,
who,
));

// Check if we can reach consensus
Self::try_reach_consensus(project_id)?;

Ok(())
}

/// Challenge an attestation (costs stake if wrong)
#[weight = 30_000]
pub fn open_dispute(
origin,
attestation_id: T::Hash,
reason: Vec<u8>,
) -> DispatchResult {
let who = ensure_signed(origin)?;

// Challenger must have stake
let challenger = Self::oracle_provider(&who)
.ok_or(Error::<T>::OracleNotRegistered)?;

// Create dispute
let dispute = DisputeState {
challenger: who.clone(),
attestation_id: attestation_id.clone(),
reason,
opened_at: <frame_system::Pallet<T>>::block_number(),
status: DisputeStatus::Open,
};

ActiveDisputes::<T>::insert(attestation_id.clone(), dispute);

Self::deposit_event(RawEvent::DisputeOpened(attestation_id, who));

Ok(())
}
}
}

impl<T: Config> Module<T> {
/// Attempt to reach consensus from multiple attestations
fn try_reach_consensus(project_id: ProjectId) -> DispatchResult {
// Collect all attestations for project
let attestations: Vec<_> = ProjectAttestations::<T>::iter_prefix(project_id)
.map(|(_, attestation)| attestation)
.collect();

// Need minimum N attestations
if attestations.len() < T::MinimumAttestations::get() as usize {
return Ok(());
}

// Weight attestations by oracle reputation and confidence
let consensus_metrics = Self::calculate_weighted_consensus(&attestations);

// Store consensus result
ConsensusMetrics::insert(project_id, consensus_metrics.clone());

let metrics_hash = T::Hashing::hash_of(&consensus_metrics);
Self::deposit_event(RawEvent::ConsensusReached(project_id, metrics_hash));

Ok(())
}

/// Calculate reputation-weighted consensus
fn calculate_weighted_consensus(
attestations: &[EcologicalAttestation<T::AccountId, T::Hash>],
) -> EcologicalMetrics {
let mut weighted_sum = EcologicalMetrics::default();
let mut total_weight = 0u64;

for attestation in attestations {
if let Some(provider) = Self::oracle_provider(&attestation.oracle_provider) {
// Weight = reputation * confidence_level
let weight = provider.reputation_score 
* attestation.confidence_level as u64;

// Weighted sum of each metric
weighted_sum.carbon_sequestered_tonnes += 
attestation.metrics.carbon_sequestered_tonnes * weight;
weighted_sum.biodiversity_score += 
attestation.metrics.biodiversity_score * weight as u32;
// ... other metrics

total_weight += weight;
}
}

// Divide by total weight to get consensus
if total_weight > 0 {
weighted_sum.carbon_sequestered_tonnes /= total_weight;
weighted_sum.biodiversity_score /= total_weight as u32;
// ... other metrics
}

weighted_sum
}

/// Calculate credit capacity from ecological metrics
pub fn calculate_credit_capacity(
metrics: &EcologicalMetrics,
) -> Result<Balance, DispatchError> {
let mut capacity = 0u64;

// Carbon component (using market-based valuation)
let carbon_value = metrics.carbon_sequestered_tonnes 
* Self::valuation_coefficients(MetricType::CarbonPerTonne);
capacity += carbon_value;

// Biodiversity component
let biodiversity_value = (metrics.biodiversity_score as u64)
* (metrics.habitat_hectares)
* Self::valuation_coefficients(MetricType::BiodiversityScore);
capacity += biodiversity_value / 1000; // Normalize

// Soil health component
let soil_value = (metrics.soil_organic_matter_percent as u64)
* Self::valuation_coefficients(MetricType::SoilHealth);
capacity += soil_value;

// Water systems component
let water_value = (metrics.water_quality_index as u64)
* (metrics.watershed_area_hectares)
* Self::valuation_coefficients(MetricType::WaterQuality);
capacity += water_value / 100;

// Social impact multiplier
let social_multiplier = 1000 + (metrics.jobs_created as u64 * 10);
capacity = capacity * social_multiplier / 1000;

Ok(capacity.into())
}
}

Oracle Network Topology

/// Decentralized oracle network with redundancy
pub struct OracleNetworkTopology {
// Primary oracle tier (high-reputation, specialized)
primary_oracles: Vec<OracleNode>,

// Secondary oracle tier (cross-validation)
secondary_oracles: Vec<OracleNode>,

// Data source integrations
satellite_imagery_apis: Vec<RemoteSensingAPI>,
iot_sensor_networks: Vec<IoTNetwork>,
field_verification_teams: Vec<FieldTeam>,

// Consensus mechanism
consensus_protocol: ConsensusProtocol,
}

pub struct RemoteSensingAPI {
provider: ApiProvider, // e.g., Planet Labs, Sentinel Hub
api_endpoint: String,
data_types: Vec<RemoteSensingDataType>,
}

pub enum RemoteSensingDataType {
NDVI, // Normalized Difference Vegetation Index
LAI, // Leaf Area Index
LandCover,
SoilMoisture,
Biomass,
}

pub struct IoTNetwork {
network_id: NetworkId,
sensor_locations: Vec<GeoCoordinate>,
sensor_types: Vec<SensorType>,
data_frequency: Duration,
}

pub enum SensorType {
SoilMoisture,
SoilPH,
AirQuality,
WaterQuality,
Temperature,
BiodiversityAcoustic,
}

impl OracleNetworkTopology {
/// Aggregate data from multiple sources
pub async fn aggregate_ecological_data(
&self,
project_id: ProjectId,
time_range: TimeRange,
) -> Result<EcologicalMetrics, Error> {

// Fetch satellite imagery data
let remote_sensing_data = self.fetch_remote_sensing_data(
project_id,
time_range,
).await?;

// Fetch IoT sensor data
let iot_data = self.fetch_iot_data(
project_id,
time_range,
).await?;

// Request field verification
let field_data = self.request_field_verification(
project_id,
).await?;

// Combine data sources with confidence weighting
let combined_metrics = self.combine_data_sources(
remote_sensing_data,
iot_data,
field_data,
)?;

Ok(combined_metrics)
}

/// Machine learning model for data fusion
fn combine_data_sources(
&self,
remote: RemoteSensingData,
iot: IoTData,
field: FieldData,
) -> Result<EcologicalMetrics, Error> {
// Use trained ML model to fuse heterogeneous data
let carbon_estimate = self.estimate_carbon_sequestration(
&remote.ndvi_timeseries,
&iot.soil_carbon_readings,
&field.biomass_measurements,
)?;

let biodiversity_score = self.estimate_biodiversity(
&remote.land_cover_classification,
&iot.acoustic_sensors,
&field.species_survey,
)?;

// ... other metrics

Ok(EcologicalMetrics {
carbon_sequestered_tonnes: carbon_estimate,
biodiversity_score,
// ... remaining fields
})
}
}

Integration with External Data Sources

# docker-compose-oracles.yml
version: '3.8'

services:
# Satellite imagery processor
remote-sensing-processor:
image: cryptosaint/remote-sensing-processor:latest
environment:
- PLANET_API_KEY=${PLANET_API_KEY}
- SENTINEL_HUB_CLIENT_ID=${SENTINEL_CLIENT_ID}
- GEE_SERVICE_ACCOUNT=${GEE_SERVICE_ACCOUNT}
volumes:
- ./models:/models
- ./data/imagery:/data
networks:
- oracle-network

# IoT data aggregator
iot-aggregator:
image: cryptosaint/iot-aggregator:latest
environment:
- MQTT_BROKER=mqtt://iot-broker:1883
- INFLUXDB_URL=http://influxdb:8086
depends_on:
- influxdb
- mqtt-broker
networks:
- oracle-network

# Machine learning inference service
ml-inference:
image: cryptosaint/ml-inference:latest
deploy:
resources:
reservations:
devices:
- driver: nvidia
count: 1
capabilities: [gpu]
volumes:
- ./models/carbon-estimation:/models/carbon
- ./models/biodiversity:/models/biodiversity
environment:
- MODEL_CARBON=/models/carbon/model.onnx
- MODEL_BIODIVERSITY=/models/biodiversity/model.onnx
networks:
- oracle-network

# IPFS node for storing verification data
ipfs-node:
image: ipfs/go-ipfs:latest
volumes:
- ipfs-data:/data/ipfs
ports:
- "4001:4001"
- "5001:5001"
- "8080:8080"
networks:
- oracle-network

# Time-series database for sensor data
influxdb:
image: influxdb:2.7
volumes:
- influxdb-data:/var/lib/influxdb2
environment:
- INFLUXDB_DB=ecological_metrics
- INFLUXDB_ADMIN_TOKEN=${INFLUXDB_TOKEN}
networks:
- oracle-network

# MQTT broker for IoT devices
mqtt-broker:
image: eclipse-mosquitto:latest
volumes:
- ./mqtt/config:/mosquitto/config
- mqtt-data:/mosquitto/data
networks:
- oracle-network

networks:
oracle-network:
driver: bridge

volumes:
ipfs-data:
influxdb-data:
mqtt-data:

Path 2: Zero-Knowledge Proof Circuits for Private Credit Verification

The Challenge

Contributors want to prove they have sufficient credit capacity to bridge without revealing:

  • Their exact reputation score

  • Their complete contribution history

  • The specific ecological projects they’re involved in

  • Their bioregional attestations

ZK-SNARK Circuit Architecture

// Use arkworks for zk-SNARKs
use ark_crypto_primitives::{
snark::{SNARK, CircuitSpecificSetupSNARK},
crh::{TwoToOneCRH, CRH},
};
use ark_ff::PrimeField;
use ark_relations::{
lc,
r1cs::{ConstraintSynthesizer, ConstraintSystemRef, SynthesisError},
};
use ark_std::rand::Rng;

/// Credit capacity proof circuit
/// Proves: "I have credit capacity >= threshold" without revealing exact amount
pub struct CreditCapacityCircuit<F: PrimeField> {
// Private inputs (witness)
reputation_score: Option<F>,
ecological_metrics: Option<Vec<F>>,
contribution_history: Option<Vec<F>>,
bioregional_attestations: Option<Vec<F>>,

// Public inputs
pub threshold: F,
pub credit_capacity_commitment: F, // Pedersen commitment
pub merkle_root: F, // Root of reputation tree
}

impl<F: PrimeField> ConstraintSynthesizer<F> for CreditCapacityCircuit<F> {
fn generate_constraints(
self,
cs: ConstraintSystemRef<F>,
) -> Result<(), SynthesisError> {
// Allocate private witness variables
let reputation = cs.new_witness_variable(|| {
self.reputation_score.ok_or(SynthesisError::AssignmentMissing)
})?;

let eco_metrics: Vec<_> = self.ecological_metrics
.ok_or(SynthesisError::AssignmentMissing)?
.iter()
.map(|&m| cs.new_witness_variable(|| Ok(m)))
.collect::<Result<_, _>>()?;

// Allocate public input variables
let threshold_var = cs.new_input_variable(|| Ok(self.threshold))?;
let commitment_var = cs.new_input_variable(|| Ok(self.credit_capacity_commitment))?;
let merkle_root_var = cs.new_input_variable(|| Ok(self.merkle_root))?;

// Constraint 1: Verify reputation is in valid range (0-1000)
// reputation >= 0 (implicit from field)
// reputation <= 1000
cs.enforce_constraint(
lc!() + reputation,
lc!() + Variable::One,
lc!() + (F::from(1000u64), Variable::One),
)?;

// Constraint 2: Calculate credit capacity from inputs
// capacity = reputation_factor * eco_factor * contribution_factor

// Reputation factor: reputation / 1000 (normalized 0-1)
let reputation_factor = cs.new_witness_variable(|| {
let rep = self.reputation_score.ok_or(SynthesisError::AssignmentMissing)?;
Ok(rep * F::from(1000u64).inverse().unwrap())
})?;

cs.enforce_constraint(
lc!() + (F::from(1000u64), reputation_factor),
lc!() + Variable::One,
lc!() + reputation,
)?;

// Ecological factor: sum of weighted metrics
let mut eco_sum = lc!();
for (i, &metric_var) in eco_metrics.iter().enumerate() {
let weight = F::from((i + 1) as u64); // Example weights
eco_sum = eco_sum + (weight, metric_var);
}

let eco_factor = cs.new_witness_variable(|| {
let metrics = self.ecological_metrics
.ok_or(SynthesisError::AssignmentMissing)?;
let sum: F = metrics.iter()
.enumerate()
.map(|(i, &m)| m * F::from((i + 1) as u64))
.sum();
Ok(sum)
})?;

cs.enforce_constraint(
lc!() + eco_factor,
lc!() + Variable::One,
eco_sum,
)?;

// Constraint 3: capacity >= threshold
// We prove: capacity - threshold >= 0
let capacity = cs.new_witness_variable(|| {
// Calculate actual capacity from witness
let rep = self.reputation_score.ok_or(SynthesisError::AssignmentMissing)?;
let eco: F = self.ecological_metrics
.ok_or(SynthesisError::AssignmentMissing)?
.iter()
.enumerate()
.map(|(i, &m)| m * F::from((i + 1) as u64))
.sum();

// Simplified capacity calculation
Ok(rep * eco)
})?;

// Prove capacity >= threshold
// This requires range proof - capacity - threshold is non-negative
let diff = cs.new_witness_variable(|| {
let cap = self.reputation_score.ok_or(SynthesisError::AssignmentMissing)?
* self.ecological_metrics
.ok_or(SynthesisError::AssignmentMissing)?
.iter()
.sum::<F>();
Ok(cap - self.threshold)
})?;

cs.enforce_constraint(
lc!() + capacity,
lc!() + Variable::One,
lc!() + diff + threshold_var,
)?;

// Range proof for diff >= 0 (using bit decomposition)
self.range_proof(cs.clone(), diff, 64)?;

// Constraint 4: Verify Pedersen commitment
// commitment = g^capacity * h^randomness
let randomness = cs.new_witness_variable(|| {
Ok(F::rand(&mut ark_std::test_rng()))
})?;

// This would use Pedersen hash gadget in practice
// For now, simplified constraint
cs.enforce_constraint(
lc!() + commitment_var,
lc!() + Variable::One,
lc!() + capacity + randomness,
)?;

// Constraint 5: Verify membership in reputation Merkle tree
self.verify_merkle_path(
cs.clone(),
reputation,
merkle_root_var,
)?;

Ok(())
}
}

impl<F: PrimeField> CreditCapacityCircuit<F> {
/// Range proof gadget: proves value fits in n bits (is non-negative)
fn range_proof(
&self,
cs: ConstraintSystemRef<F>,
value: Variable,
num_bits: usize,
) -> Result<(), SynthesisError> {
// Decompose value into bits
let bits: Vec<Variable> = (0..num_bits)
.map(|i| {
cs.new_witness_variable(|| {
// Extract bit i from value
Ok(F::from((/* extract bit */ 0u64)))
})
})
.collect::<Result<_, _>>()?;

// Constrain each bit to be 0 or 1
for &bit in &bits {
// bit * (1 - bit) == 0
cs.enforce_constraint(
lc!() + bit,
lc!() + Variable::One - bit,
lc!(),
)?;
}

// Constrain sum of bits equals value
let mut sum = lc!();
for (i, &bit) in bits.iter().enumerate() {
let coeff = F::from(2u64).pow(&[i as u64]);
sum = sum + (coeff, bit);
}

cs.enforce_constraint(
lc!() + value,
lc!() + Variable::One,
sum,
)?;

Ok(())
}

/// Merkle path verification gadget
fn verify_merkle_path(
&self,
cs: ConstraintSystemRef<F>,
leaf: Variable,
root: Variable,
) -> Result<(), SynthesisError> {
// Simplified - would use Poseidon hash in practice
// Verifies that leaf is in tree with given root

// This would iterate through merkle path
// For each level: hash(current, sibling) = parent

// Placeholder constraint
cs.enforce_constraint(
lc!() + leaf,
lc!() + Variable::One,
lc!() + root,
)?;

Ok(())
}
}

/// Proof generation for bridge transactions
pub struct CreditProofGenerator {
proving_key: ProvingKey,
verification_key: VerificationKey,
}

impl CreditProofGenerator {
/// Generate proof of credit capacity
pub fn prove_credit_capacity<R: Rng>(
&self,
rng: &mut R,
reputation_score: u64,
ecological_metrics: Vec<u64>,
threshold: u64,
) -> Result<Proof, Error> {
// Convert to field elements
let reputation = F::from(reputation_score);
let metrics: Vec<F> = ecological_metrics
.iter()
.map(|&m| F::from(m))
.collect();
let threshold_f = F::from(threshold);

// Generate Pedersen commitment
let (commitment, randomness) = self.commit_to_capacity(
reputation,
&metrics,
rng,
)?;

// Get Merkle path for reputation
let merkle_root = self.get_reputation_tree_root();

// Create circuit instance
let circuit = CreditCapacityCircuit {
reputation_score: Some(reputation),
ecological_metrics: Some(metrics),
contribution_history: Some(vec![]), // Fill from storage
bioregional_attestations: Some(vec![]),
threshold: threshold_f,
credit_capacity_commitment: commitment,
merkle_root,
};

// Generate proof
let proof = Groth16::prove(&self.proving_key, circuit, rng)?;

Ok(proof)
}

/// Verify proof on-chain (cheap!)
pub fn verify_proof(
&self,
proof: &Proof,
public_inputs: &[F],
) -> Result<bool, Error> {
Groth16::verify(&self.verification_key, public_inputs, proof)
}
}

Privacy-Preserving Bridge Transaction Flow

/// Bridge transaction with ZK proofs
pub struct PrivateBridgeTransaction {
// Public info
pub sender_commitment: CommitmentHash,
pub amount_commitment: CommitmentHash,
pub target_currency: BricsCurrency,
pub recipient: BricsPayAddress,

// ZK proofs
pub credit_capacity_proof: Proof,
pub reputation_membership_proof: Proof,
pub ecological_backing_proof: Proof,

// Nullifier (prevents double-spending)
pub nullifier: Nullifier,
}

impl PrivateBridgeTransaction {
/// Create private bridge transaction
pub fn create<R: Rng>(
rng: &mut R,
credit: &ContributionCredit,
amount: Balance,
target_currency: BricsCurrency,
recipient: BricsPayAddress,
) -> Result<Self, Error> {
// Generate commitments
let sender_commitment = commit_to_account(
&credit.holder,
rng,
)?;

let amount_commitment = commit_to_amount(
amount,
rng,
)?;

// Generate proofs
let proof_generator = CreditProofGenerator::new();

let credit_capacity_proof = proof_generator.prove_credit_capacity(
rng,
credit.reputation_score,
extract_ecological_metrics(credit),
amount, // Prove capacity >= amount
)?;

let reputation_proof = proof_generator.prove_reputation_membership(
rng,
credit.reputation_score,
)?;

let ecological_proof = proof_generator.prove_ecological_backing(
rng,
&credit.ecological_impact,
amount,
)?;

// Generate nullifier to prevent double-spending
let nullifier = generate_nullifier(
&credit.holder,
&credit.mutual_credit_balance,
rng,
)?;

Ok(Self {
sender_commitment,
amount_commitment,
target_currency,
recipient,
credit_capacity_proof,
reputation_membership_proof: reputation_proof,
ecological_backing_proof: ecological_proof,
nullifier,
})
}

/// Verify transaction without revealing private data
pub fn verify(&self) -> Result<bool, Error> {
// Verify all ZK proofs
let capacity_valid = verify_credit_capacity_proof(
&self.credit_capacity_proof,
&self.sender_commitment,
&self.amount_commitment,
)?;

let reputation_valid = verify_reputation_proof(
&self.reputation_membership_proof,
&self.sender_commitment,
)?;

let ecological_valid = verify_ecological_proof(
&self.ecological_backing_proof,
&self.amount_commitment,
)?;

// Check nullifier hasn't been used
let nullifier_fresh = !is_nullifier_spent(&self.nullifier)?;

Ok(capacity_valid && reputation_valid && ecological_valid && nullifier_fresh)
}
}

I’ll now develop the final two technical paths for your regenerative credit bridge system.

Path 3: Economic Game Theory of Liquidity Provision

The Core Challenge

Your system has asymmetric value flows: CryptoSaint credits are contribution-based (non-extractive) while BRICS Pay requires fiat currency liquidity. Liquidity providers (LPs) must be incentivized to bridge this gap without undermining regenerative principles.

Game-Theoretic Model

Players

  1. Contribution Credit Holders - Want to convert ecological value to currency

  2. Liquidity Providers - Stake BRICS currencies, earn fees

  3. Bridge Validators - Operate infrastructure, validate attestations

  4. Oracle Providers - Attest to ecological metrics

  5. Speculators - May try to arbitrage or extract value

Strategy Space

/// Core game-theoretic primitives
use sp_runtime::{Perbill, Permill};
use frame_support::traits::Get;

/// LP strategy types
#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub enum LPStrategy {
    /// Passive: Provide liquidity, collect fees
    PassiveFarming {
        capital: Balance,
        duration: BlockNumber,
    },
    
    /// Active: Dynamically adjust positions based on volatility
    ActiveMarketMaking {
        capital: Balance,
        rebalance_frequency: BlockNumber,
        risk_tolerance: Perbill,
    },
    
    /// Altruistic: Accept lower returns to support regenerative projects
    RegenerativeFocus {
        capital: Balance,
        preferred_bioregions: Vec<BioregionId>,
        min_ecological_score: u32,
    },
    
    /// Extractive: Maximize short-term profit
    ExtractiveFocus {
        capital: Balance,
        max_exposure_time: BlockNumber,
    },
}

/// Payoff structure for LPs
#[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
pub struct LPPayoff {
    // Direct financial returns
    pub trading_fees: Balance,
    pub bridge_fees: Balance,
    pub slippage_capture: Balance,
    
    // Opportunity cost
    pub capital_locked: Balance,
    pub alternative_yield: Perbill, // What they could earn elsewhere
    
    // Reputation/social returns
    pub reputation_gain: u64,
    pub ecological_impact_credit: Balance,
    
    // Risks
    pub impermanent_loss: Balance,
    pub smart_contract_risk: Perbill,
    pub oracle_failure_risk: Perbill,
}

impl LPPayoff {
    /// Calculate net utility for LP
    pub fn net_utility(&self, lp_preferences: &LPPreferences) -> i128 {
        let financial = (self.trading_fees 
            + self.bridge_fees 
            + self.slippage_capture) as i128
            - (self.impermanent_loss as i128);
        
        let opportunity_cost = -(self.capital_locked as i128) 
            * (self.alternative_yield.deconstruct() as i128) 
            / 1_000_000;
        
        let reputation_value = (self.reputation_gain as i128) 
            * (lp_preferences.reputation_weight as i128);
        
        let ecological_value = (self.ecological_impact_credit as i128)
            * (lp_preferences.ecological_weight as i128);
        
        // Risk-adjusted return
        let risk_penalty = (financial as i128) 
            * (self.smart_contract_risk.deconstruct() as i128
                + self.oracle_failure_risk.deconstruct() as i128)
            / 1_000_000;
        
        financial + reputation_value + ecological_value 
            + opportunity_cost - risk_penalty
    }
}

#[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
pub struct LPPreferences {
    /// How much LP values reputation (0-1000)
    pub reputation_weight: u32,
    
    /// How much LP values ecological impact (0-1000)
    pub ecological_weight: u32,
    
    /// Risk aversion (0 = risk-neutral, 1000 = very risk-averse)
    pub risk_aversion: u32,
    
    /// Time horizon (blocks)
    pub investment_horizon: BlockNumber,
}

Nash Equilibrium Analysis

Scenario 1: Pure Competition (No Cooperation)

/// Model competitive equilibrium
pub struct CompetitiveEquilibrium {
    pub num_lps: u32,
    pub total_liquidity: Balance,
    pub average_fee_rate: Perbill,
    pub market_clearing_rate: Perbill,
}

impl CompetitiveEquilibrium {
    /// Calculate Nash equilibrium fee rate
    pub fn calculate_equilibrium(
        demand_curve: &DemandCurve,
        supply_curve: &SupplyCurve,
    ) -> Result<Self, Error> {
        // In pure competition, LPs compete on fees until profit → 0
        // Equilibrium: fee_rate = marginal_cost + risk_premium
        
        let marginal_cost = supply_curve.calculate_marginal_cost();
        let risk_premium = supply_curve.calculate_risk_premium();
        
        let equilibrium_fee = marginal_cost + risk_premium;
        
        // At this fee, demand = supply
        let equilibrium_volume = demand_curve.quantity_at_price(equilibrium_fee);
        let num_lps = supply_curve.lps_at_volume(equilibrium_volume);
        
        Ok(Self {
            num_lps,
            total_liquidity: equilibrium_volume,
            average_fee_rate: equilibrium_fee,
            market_clearing_rate: equilibrium_fee,
        })
    }
    
    /// This is unstable - race to bottom on fees
    pub fn is_sustainable(&self) -> bool {
        // If fees < cost + risk, LPs exit
        // System breaks down
        self.average_fee_rate.deconstruct() >= 1000 // 0.1% minimum
    }
}

Problem: Pure competition leads to unsustainably low fees, LPs exit, bridge fails.

Scenario 2: Coordinated Liquidity Provision

/// Cooperative LP mechanism
pub struct CooperativeLiquidityPool {
    // DAO-governed parameters
    pub min_fee_rate: Perbill,
    pub max_fee_rate: Perbill,
    pub target_utilization: Perbill, // 80% ideal
    
    // Dynamic fee adjustment
    pub fee_adjustment_curve: FeeAdjustmentCurve,
    
    // Reputation-weighted governance
    pub governance_token: GovernanceToken,
}

impl CooperativeLiquidityPool {
    /// Calculate optimal fee using AMM-style curve
    pub fn calculate_dynamic_fee(
        &self,
        utilization_rate: Perbill,
    ) -> Perbill {
        // Fee increases with utilization to prevent exhaustion
        // f(u) = min_fee + (max_fee - min_fee) * (u / target)^2
        
        let utilization = utilization_rate.deconstruct() as u128;
        let target = self.target_utilization.deconstruct() as u128;
        
        if utilization <= target {
            // Below target: linear increase
            let range = self.max_fee_rate.deconstruct() as u128
                - self.min_fee_rate.deconstruct() as u128;
            let fee = self.min_fee_rate.deconstruct() as u128
                + (range * utilization / target);
            Perbill::from_parts(fee as u32)
        } else {
            // Above target: exponential increase
            let excess = utilization - target;
            let range = self.max_fee_rate.deconstruct() as u128
                - self.min_fee_rate.deconstruct() as u128;
            let fee = self.min_fee_rate.deconstruct() as u128
                + range + (range * excess * excess / (target * target));
            Perbill::from_parts(fee.min(1_000_000) as u32)
        }
    }
    
    /// Distribute fees based on contribution AND reputation
    pub fn distribute_fees(
        &mut self,
        total_fees: Balance,
        lps: &[(AccountId, LPPosition)],
    ) -> Result<(), Error> {
        let mut weighted_stakes = Vec::new();
        let mut total_weight = 0u128;
        
        for (lp_id, position) in lps {
            // Weight = liquidity * reputation_multiplier * time_factor
            let reputation = Self::get_reputation(lp_id)?;
            let time_factor = self.calculate_time_bonus(position);
            
            let weight = (position.liquidity as u128)
                * (reputation as u128)
                * (time_factor as u128)
                / 1_000_000;
            
            weighted_stakes.push((lp_id.clone(), weight));
            total_weight += weight;
        }
        
        // Distribute proportionally
        for (lp_id, weight) in weighted_stakes {
            let share = (total_fees as u128) * weight / total_weight;
            Self::credit_lp_account(&lp_id, share as Balance)?;
        }
        
        Ok(())
    }
    
    /// Time-weighted bonus for long-term LPs
    fn calculate_time_bonus(&self, position: &LPPosition) -> u32 {
        let duration = current_block() - position.entry_block;
        
        // Bonus increases with time, caps at 2x after 1 year
        let year_blocks = 5_256_000u64; // ~1 year at 6s blocks
        let bonus = 1000 + (duration as u64).min(year_blocks) * 1000 / year_blocks;
        bonus as u32
    }
}

Mechanism Design: Incentive-Compatible LP System

Key Innovation: Regenerative Staking

/// LPs can stake in "Regenerative Pools" for higher returns
pub struct RegenerativeStakingPool {
    // Standard liquidity provision
    pub base_liquidity: Balance,
    pub base_fee_rate: Perbill,
    
    // Regenerative enhancement
    pub ecological_multiplier: Perbill, // 1.5x fees for eco-focused LPs
    pub locked_period: BlockNumber, // Must lock for 6 months
    pub min_reputation_score: u64, // Only high-reputation LPs
    
    // Impact tracking
    pub funded_projects: Vec<ProjectId>,
    pub ecological_impact_generated: EcologicalMetrics,
}

impl RegenerativeStakingPool {
    /// Enhanced payoff for regenerative LPs
    pub fn calculate_regenerative_payoff(
        &self,
        base_fees: Balance,
        lp_position: &LPPosition,
    ) -> LPPayoff {
        // Base financial return
        let enhanced_fees = (base_fees as u128)
            * (self.ecological_multiplier.deconstruct() as u128)
            / 1_000_000;
        
        // Reputation gain from supporting regeneration
        let reputation_gain = self.calculate_reputation_increase(lp_position);
        
        // Ecological credits (tradeable)
        let eco_credits = self.calculate_ecological_credits(lp_position);
        
        LPPayoff {
            trading_fees: enhanced_fees as Balance,
            bridge_fees: enhanced_fees as Balance,
            reputation_gain,
            ecological_impact_credit: eco_credits,
            ..Default::default()
        }
    }
    
    /// Reputation increases based on impact of funded projects
    fn calculate_reputation_increase(&self, position: &LPPosition) -> u64 {
        let mut reputation_delta = 0u64;
        
        for project_id in &self.funded_projects {
            if let Some(impact) = Self::get_project_impact(project_id) {
                // LP shares credit proportional to their stake
                let lp_share = (position.liquidity as u128)
                    / (self.base_liquidity as u128);
                
                let project_reputation = (impact.reputation_value() as u128)
                    * lp_share
                    / 1_000_000;
                
                reputation_delta += project_reputation as u64;
            }
        }
        
        reputation_delta
    }
}

Preventing Extractive Behavior

Sybil Resistance via Staked Reputation

/// Anti-sybil mechanism for LPs
pub struct StakedReputationSystem {
    pub min_reputation_stake: Balance,
    pub reputation_decay_rate: Perbill,
    pub slashing_conditions: Vec<SlashingCondition>,
}

#[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
pub enum SlashingCondition {
    /// LP exits during critical liquidity shortage
    AbandonmentSlash {
        threshold_utilization: Perbill,
        slash_percent: Perbill,
    },
    
    /// LP manipulates oracle data
    OracleManipulationSlash {
        evidence_threshold: u32,
        slash_percent: Perbill,
    },
    
    /// LP front-runs bridge transactions
    FrontRunningSlash {
        mev_threshold: Balance,
        slash_percent: Perbill,
    },
    
    /// LP provides liquidity to extractive actors
    ExtractionSupportSlash {
        extractive_score_threshold: u32,
        slash_percent: Perbill,
    },
}

impl StakedReputationSystem {
    /// Check if LP behavior warrants slashing
    pub fn evaluate_lp_behavior(
        &self,
        lp: &AccountId,
        action: &LPAction,
        context: &MarketContext,
    ) -> Result<Option<SlashingEvent>, Error> {
        for condition in &self.slashing_conditions {
            match condition {
                SlashingCondition::AbandonmentSlash { threshold_utilization, slash_percent } => {
                    if let LPAction::WithdrawLiquidity(amount) = action {
                        if context.current_utilization >= *threshold_utilization {
                            // LP is abandoning during crisis
                            let penalty = (*amount as u128)
                                * (slash_percent.deconstruct() as u128)
                                / 1_000_000;
                            
                            return Ok(Some(SlashingEvent {
                                lp: lp.clone(),
                                amount: penalty as Balance,
                                reason: "Abandonment during liquidity crisis".into(),
                            }));
                        }
                    }
                }
                
                SlashingCondition::FrontRunningSlash { mev_threshold, slash_percent } => {
                    if Self::detect_front_running(lp, action, context)? > *mev_threshold {
                        // LP is extracting MEV
                        let stake = Self::get_lp_stake(lp)?;
                        let penalty = (stake as u128)
                            * (slash_percent.deconstruct() as u128)
                            / 1_000_000;
                        
                        return Ok(Some(SlashingEvent {
                            lp: lp.clone(),
                            amount: penalty as Balance,
                            reason: "Front-running detected".into(),
                        }));
                    }
                }
                
                _ => { /* Check other conditions */ }
            }
        }
        
        Ok(None)
    }
}

Optimal Liquidity Provisioning Strategy

Multi-Agent Simulation

/// Simulate LP strategies to find optimal behavior
pub struct LiquiditySimulation {
    pub agents: Vec<SimulatedLP>,
    pub market_params: MarketParameters,
    pub simulation_rounds: u32,
}

pub struct SimulatedLP {
    pub strategy: LPStrategy,
    pub capital: Balance,
    pub reputation: u64,
    pub accumulated_payoff: i128,
}

impl LiquiditySimulation {
    /// Run evolutionary game theory simulation
    pub fn run_simulation(&mut self) -> SimulationResults {
        let mut results = SimulationResults::new();
        
        for round in 0..self.simulation_rounds {
            // Each LP chooses action based on strategy
            let actions: Vec<_> = self.agents
                .iter()
                .map(|lp| lp.choose_action(&self.market_params))
                .collect();
            
            // Market responds to aggregate behavior
            let market_state = self.market_params.evolve(&actions);
            
            // Calculate payoffs
            for (i, lp) in self.agents.iter_mut().enumerate() {
                let payoff = self.calculate_payoff(
                    lp,
                    &actions[i],
                    &market_state,
                );
                lp.accumulated_payoff += payoff;
            }
            
            // LPs adapt strategies (learning)
            self.evolve_strategies(&market_state);
            
            results.record_round(round, &self.agents, &market_state);
        }
        
        results
    }
    
    /// LPs learn and adapt strategies
    fn evolve_strategies(&mut self, market_state: &MarketState) {
        // Replicate successful strategies (evolutionary dynamics)
        let avg_payoff: i128 = self.agents
            .iter()
            .map(|lp| lp.accumulated_payoff)
            .sum::<i128>() / (self.agents.len() as i128);
        
        for lp in self.agents.iter_mut() {
            if lp.accumulated_payoff < avg_payoff {
                // Below average: consider switching strategy
                if rand::random::<f64>() < 0.1 {
                    lp.strategy = self.select_better_strategy(market_state);
                }
            }
        }
    }
    
    fn select_better_strategy(&self, market: &MarketState) -> LPStrategy {
        // Find highest-performing strategy in current market
        let best_strategy = self.agents
            .iter()
            .max_by_key(|lp| lp.accumulated_payoff)
            .map(|lp| lp.strategy.clone())
            .unwrap();
        
        // Add some mutation/exploration
        self.mutate_strategy(best_strategy, market)
    }
}

/// Results show which strategies dominate
pub struct SimulationResults {
    pub dominant_strategy: LPStrategy,
    pub equilibrium_fee_rate: Perbill,
    pub total_liquidity: Balance,
    pub system_stability: f64, // 0-1
    pub regenerative_impact: EcologicalMetrics,
}

impl SimulationResults {
    pub fn optimal_mechanism_design(&self) -> MechanismParameters {
        // Based on simulation, design mechanism that:
        // 1. Attracts sufficient liquidity
        // 2. Prevents extractive behavior
        // 3. Rewards regenerative focus
        // 4. Maintains stability
        
        MechanismParameters {
            min_fee_rate: self.calculate_sustainable_min_fee(),
            regenerative_bonus: self.calculate_optimal_bonus(),
            slashing_severity: self.calculate_optimal_slashing(),
            reputation_weight: self.calculate_reputation_importance(),
        }
    }
}

Dynamic Fee Mechanism

/// Adaptive fee mechanism responding to market conditions
pub struct AdaptiveFeeController {
    // Current state
    pub current_fee: Perbill,
    pub target_utilization: Perbill,
    pub utilization_history: Vec<(BlockNumber, Perbill)>,
    
    // Control parameters
    pub adjustment_speed: Perbill, // How fast fees adjust
    pub sensitivity: Perbill, // How responsive to utilization changes
}

impl AdaptiveFeeController {
    /// PID controller for fee adjustment
    pub fn update_fee(&mut self, current_utilization: Perbill) -> Perbill {
        // Proportional term: distance from target
        let error = (current_utilization.deconstruct() as i64)
            - (self.target_utilization.deconstruct() as i64);
        let proportional = error;
        
        // Integral term: accumulated error
        let integral = self.utilization_history
            .iter()
            .map(|(_, u)| {
                (u.deconstruct() as i64) - (self.target_utilization.deconstruct() as i64)
            })
            .sum::<i64>();
        
        // Derivative term: rate of change
        let derivative = if self.utilization_history.len() >= 2 {
            let recent = self.utilization_history.last().unwrap().1.deconstruct() as i64;
            let previous = self.utilization_history[self.utilization_history.len() - 2].1.deconstruct() as i64;
            recent - previous
        } else {
            0
        };
        
        // PID formula
        let adjustment = (proportional * 100 + integral / 10 + derivative * 50) / 1000;
        
        // Apply adjustment
        let new_fee = (self.current_fee.deconstruct() as i64 + adjustment)
            .max(100) // 0.01% minimum
            .min(100_000) as u32; // 10% maximum
        
        self.current_fee = Perbill::from_parts(new_fee);
        self.utilization_history.push((current_block(), current_utilization));
        
        self.current_fee
    }
}

Impermanent Loss Protection

/// Protect LPs from impermanent loss
pub struct ImpermanentLossInsurance {
    pub insurance_fund: Balance,
    pub coverage_ratio: Perbill, // % of IL covered
}

impl ImpermanentLossInsurance {
    /// Calculate impermanent loss for an LP position
    pub fn calculate_impermanent_loss(
        &self,
        entry_price: Price,
        current_price: Price,
        liquidity: Balance,
    ) -> Balance {
        // IL = 2 * sqrt(price_ratio) / (1 + price_ratio) - 1
        let ratio = (current_price.0 as f64) / (entry_price.0 as f64);
        let sqrt_ratio = ratio.sqrt();
        let il_percent = 2.0 * sqrt_ratio / (1.0 + ratio) - 1.0;
        
        // Convert to absolute loss
        let loss = (liquidity as f64) * il_percent.abs();
        loss as Balance
    }
    
    /// Compensate LP for impermanent loss
    pub fn compensate_il(
        &mut self,
        lp: &AccountId,
        il_amount: Balance,
    ) -> Result<Balance, Error> {
        let compensation = (il_amount as u128)
            * (self.coverage_ratio.deconstruct() as u128)
            / 1_000_000;
        
        ensure!(
            compensation <= self.insurance_fund as u128,
            Error::InsufficientInsuranceFund
        );
        
        self.insurance_fund -= compensation as Balance;
        Self::credit_account(lp, compensation as Balance)?;
        
        Ok(compensation as Balance)
    }
}

Path 4: Smart Contract Security Patterns for Cross-Chain Atomic Swaps

Threat Model

Attack Vectors

  1. Timing Attacks: Exploiting time-lock differences between chains

  2. Oracle Manipulation: Feeding false ecological data

  3. Front-Running: MEV extraction from bridge transactions

  4. Replay Attacks: Reusing proofs across chains

  5. Collateral Manipulation: Under-collateralizing positions

  6. Reentrancy: Classic attack on swap execution

  7. DoS: Blocking legitimate swaps

Secure HTLC Implementation

// pallets/atomic-swap/src/lib.rs

use frame_support::{
    decl_module, decl_storage, decl_event, decl_error,
    traits::{Currency, ReservableCurrency, ExistenceRequirement},
    ensure,
};
use sp_runtime::traits::{Hash, CheckedSub, CheckedAdd};
use sp_std::prelude::*;

type BalanceOf<T> = <<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;

/// Secure atomic swap state
#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub struct AtomicSwap<AccountId, Balance, BlockNumber, Hash> {
    pub swap_id: Hash,
    pub initiator: AccountId,
    pub participant: AccountId,
    
    // Locked assets
    pub cryptosaint_amount: Balance,
    pub brics_amount: Balance,
    pub brics_currency: BricsCurrency,
    
    // Security parameters
    pub hash_lock: Hash,
    pub time_lock: BlockNumber,
    pub created_at: BlockNumber,
    
    // State
    pub state: SwapState,
    pub secret_revealed: Option<Vec<u8>>,
    
    // Anti-replay
    pub nonce: u64,
    pub chain_id: u32,
    
    // Collateral
    pub collateral_locked: Balance,
    pub collateral_hash: Hash,
}

#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub enum SwapState {
    Initiated,
    SecretRevealed,
    Completed,
    Refunded,
    Cancelled,
}

decl_storage! {
    trait Store for Module<T: Config> as AtomicSwap {
        /// Active swaps by ID
        Swaps get(fn swaps):
            map hasher(blake2_128_concat) T::Hash =>
            Option<AtomicSwap<T::AccountId, BalanceOf<T>, BlockNumber, T::Hash>>;
        
        /// Used secrets (prevent replay)
        UsedSecrets get(fn used_secrets):
            map hasher(blake2_128_concat) T::Hash => bool;
        
        /// Swap nonce per account (prevent replay)
        SwapNonces get(fn swap_nonces):
            map hasher(blake2_128_concat) T::AccountId => u64;
        
        /// Emergency pause flag
        EmergencyPaused get(fn emergency_paused): bool;
        
        /// Minimum time lock duration (prevent griefing)
        MinTimeLock get(fn min_time_lock): BlockNumber;
        
        /// Maximum time lock duration (prevent DoS)
        MaxTimeLock get(fn max_time_lock): BlockNumber;
    }
}

decl_event!(
    pub enum Event<T> where
        AccountId = <T as frame_system::Config>::AccountId,
        Balance = BalanceOf<T>,
        Hash = <T as frame_system::Config>::Hash,
    {
        /// Swap initiated [swap_id, initiator, participant]
        SwapInitiated(Hash, AccountId, AccountId),
        
        /// Secret revealed [swap_id, secret_hash]
        SecretRevealed(Hash, Hash),
        
        /// Swap completed [swap_id]
        SwapCompleted(Hash),
        
        /// Swap refunded [swap_id]
        SwapRefunded(Hash),
        
        /// Emergency pause activated
        EmergencyPauseActivated,
    }
);

decl_error! {
    pub enum Error for Module<T: Config> {
        /// Swap already exists
        SwapAlreadyExists,
        /// Swap not found
        SwapNotFound,
        /// Invalid time lock
        InvalidTimeLock,
        /// Time lock not expired
        TimeLockNotExpired,
        /// Time lock expired
        TimeLockExpired,
        /// Invalid secret
        InvalidSecret,
        /// Secret already used
        SecretAlreadyUsed,
        /// Invalid state transition
        InvalidStateTransition,
        /// Insufficient balance
        InsufficientBalance,
        /// System paused
        SystemPaused,
        /// Replay attack detected
        ReplayAttackDetected,
        /// Collateral insufficient
        InsufficientCollateral,
    }
}

decl_module! {
    pub struct Module<T: Config> for enum Call where origin: T::Origin {
        type Error = Error<T>;
        fn deposit_event() = default;
        
        /// Initiate atomic swap with security checks
        #[weight = 100_000]
        pub fn initiate_swap(
            origin,
            participant: T::AccountId,
            hash_lock: T::Hash,
            time_lock: BlockNumber,
            cryptosaint_amount: BalanceOf<T>,
            brics_amount: BalanceOf<T>,
            brics_currency: BricsCurrency,
            collateral_amount: BalanceOf<T>,
        ) -> DispatchResult {
            let initiator = ensure_signed(origin)?;
            
            // Security check: system not paused
            ensure!(!Self::emergency_paused(), Error::<T>::SystemPaused);
            
            // Security check: valid time lock range
            let current_block = <frame_system::Pallet<T>>::block_number();
            ensure!(
                time_lock > current_block + Self::min_time_lock(),
                Error::<T>::InvalidTimeLock
            );
            ensure!(
                time_lock < current_block + Self::max_time_lock(),
                Error::<T>::InvalidTimeLock
            );
            
            // Security check: sufficient collateral
            let required_collateral = Self::calculate_required_collateral(
                cryptosaint_amount,
                brics_amount,
            )?;
            ensure!(
                collateral_amount >= required_collateral,
                Error::<T>::InsufficientCollateral
            );
            
            // Anti-replay: increment nonce
            let nonce = Self::swap_nonces(&initiator);
            SwapNonces::<T>::insert(&initiator, nonce + 1);
            
            // Generate unique swap ID
            let swap_id = T::Hashing::hash_of(&(
                &initiator,
                &participant,
                &hash_lock,
                nonce,
                T::ChainId::get(),
                current_block,
            ));
            
            // Security check: swap doesn't exist
            ensure!(
                !Swaps::<T>::contains_key(&swap_id),
                Error::<T>::SwapAlreadyExists
            );
            
            // Lock CryptoSaint credits (reserve)
            T::Currency::reserve(&initiator, cryptosaint_amount)?;
            
            // Lock collateral
            T::Currency::reserve(&initiator, collateral_amount)?;
            
            // Create swap
            let swap = AtomicSwap {
                swap_id: swap_id.clone(),
                initiator: initiator.clone(),
                participant: participant.clone(),
                cryptosaint_amount,
                brics_amount,
                brics_currency,
                hash_lock,
                time_lock,
                created_at: current_block,
                state: SwapState::Initiated,
                secret_revealed: None,
                nonce,
                chain_id: T::ChainId::get(),
                collateral_locked: collateral_amount,
                collateral_hash: T::Hashing::hash_of(&collateral_amount),
            };
            
            Swaps::<T>::insert(&swap_id, swap);
            
            Self::deposit_event(RawEvent::SwapInitiated(
                swap_id,
                initiator,
                participant,
            ));
            
            Ok(())
        }
        
        /// Reveal secret and claim swap
        #[weight = 80_000]
        pub fn reveal_secret(
            origin,
            swap_id: T::Hash,
            secret: Vec<u8>,
        ) -> DispatchResult {
            let claimer = ensure_signed(origin)?;
            
            // Get swap
            let mut swap = Self::swaps(&swap_id)
                .ok_or(Error::<T>::SwapNotFound)?;
            
            // Security check: only participant can claim
            ensure!(claimer == swap.participant, Error::<T>::InvalidStateTransition);
            
            // Security check: not expired
            let current_block = <frame_system::Pallet<T>>::block_number();
            ensure!(
                current_block <= swap.time_lock,
                Error::<T>::TimeLockExpired
            );
            
            // Security check: correct state
            ensure!(
                swap.state == SwapState::Initiated,
                Error::<T>::InvalidStateTransition
            );
            
            // Verify secret matches hash lock
            let secret_hash = T::Hashing::hash(&secret);
            ensure!(
                secret_hash == swap.hash_lock,
                Error::<T>::InvalidSecret
            );
            
            // Anti-replay: check secret not used
            ensure!(
                !Self::used_secrets(&secret_hash),
                Error::<T>::SecretAlreadyUsed
            );
            
            // Mark secret as used
            UsedSecrets::<T>::insert(&secret_hash, true);
            
            // Update swap state
            swap.state = SwapState::SecretRevealed;
            swap.secret_revealed = Some(secret.clone());
            Swaps::<T>::insert(&swap_id, &swap);
            
            Self::deposit_event(RawEvent::SecretRevealed(swap_id, secret_hash));
            
            // Execute transfer (non-reentrant)
            Self::execute_swap_transfer(&swap)?;
            
            Ok(())
        }
        
        /// Refund after time lock expires
        #[weight = 60_000]
        pub fn refund(
            origin,
            swap_id: T::Hash,
        ) -> DispatchResult {
            let initiator = ensure_signed(origin)?;
            
            let mut swap = Self::swaps(&swap_id)
                .ok_or(Error::<T>::SwapNotFound)?;
            
            // Security check: only initiator can refund
            ensure!(initiator == swap.initiator, Error::<T>::InvalidStateTransition);
            
            // Security check: time lock expired
            let current_block = <frame_system::Pallet<T>>::block_number();
            ensure!(
                current_block > swap.time_lock,
                Error::<T>::TimeLockNotExpired
            );
            
            // Security check: not already completed
            ensure!(
                swap.state == SwapState::Initiated,
                Error::<T>::InvalidStateTransition
            );
            
            // Update state
            swap.state = SwapState::Refunded;
            Swaps::<T>::insert(&swap_id, &swap);
            
            // Unreserve locked amounts
            T::Currency::unreserve(&swap.initiator, swap.cryptosaint_amount);
            T::Currency::unreserve(&swap.initiator, swap.collateral_locked);
            
            Self::deposit_event(RawEvent::SwapRefunded(swap_id));
            
            Ok(())
        }
        
        /// Emergency pause (governance only)
        #[weight = 10_000]
        pub fn emergency_pause(origin) -> DispatchResult {
            T::EmergencyOrigin::ensure_origin(origin)?;
            
            EmergencyPaused::put(true);
            Self::deposit_event(RawEvent::EmergencyPauseActivated);
            
            Ok(())
        }
    }
}

impl<T: Config> Module<T> {
    /// Execute swap transfer with reentrancy protection
    fn execute_swap_transfer(
        swap: &AtomicSwap<T::AccountId, BalanceOf<T>, BlockNumber, T::Hash>,
    ) -> DispatchResult {
        // Reentrancy guard: check state again
        let current_swap = Self::swaps(&swap.swap_id)
            .ok_or(Error::<T>::SwapNotFound)?;
        ensure!(
            current_swap.state == SwapState::SecretRevealed,
            Error::<T>::InvalidStateTransition
        );
        
        // Transfer locked amount to participant
        T::Currency::unreserve(&swap.initiator, swap.cryptosaint_amount);
        T::Currency::transfer(
            &swap.initiator,
            &swap.participant,
            swap.cryptosaint_amount,
            ExistenceRequirement::KeepAlive,
        )?;
        
        // Return collateral to initiator
        T::Currency::unreserve(&swap.initiator, swap.collateral_locked);
        
        // Update final state
        let mut final_swap = current_swap;
        final_swap.state = SwapState::Completed;
        Swaps::<T>::insert(&swap.swap_id, final_swap);
        
        Self::deposit_event(RawEvent::SwapCompleted(swap.swap_id));
        
        Ok(())
    }
    
    /// Calculate required collateral based on risk
    fn calculate_required_collateral(
        cryptosaint_amount: BalanceOf<T>,
        brics_amount: BalanceOf<T>,
    ) -> Result<BalanceOf<T>, DispatchError> {
        // Collateral = max(cryptosaint_amount, brics_amount) * 1.5
        let max_amount = cryptosaint_amount.max(brics_amount);
        let collateral = max_amount
            .checked_mul(&150u32.into())
            .and_then(|x| x.checked_div(&100u32.into()))
            .ok_or(Error::<T>::InsufficientCollateral)?;
        
        Ok(collateral)
    }
}

Cross-Chain Message Verification

/// Secure cross-chain message passing
pub struct CrossChainMessageVerifier {
    // Validator set for each chain
    pub chain_validators: HashMap<ChainId, Vec<ValidatorPublicKey>>,
    
    // Minimum signatures required (2/3)
    pub signature_threshold: Perbill,
    
    // Message nonces to prevent replay
    pub processed_messages: HashMap<MessageHash, BlockNumber>,
}

#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub struct CrossChainMessage {
    pub source_chain: ChainId,
    pub dest_chain: ChainId,
    pub nonce: u64,
    pub payload: Vec<u8>,
    pub signatures: Vec<ValidatorSignature>,
}

impl CrossChainMessageVerifier {
    /// Verify message authenticity
    pub fn verify_message(
        &self,
        message: &CrossChainMessage,
    ) -> Result<bool, Error> {
        // Check 1: Message not replayed
        let msg_hash = Self::hash_message(message);
        if self.processed_messages.contains_key(&msg_hash) {
            return Err(Error::ReplayAttack);
        }
        
        // Check 2: Sufficient validator signatures
        let validators = self.chain_validators
            .get(&message.source_chain)
            .ok_or(Error::UnknownChain)?;
        
        let required_sigs = (validators.len() as u128)
            * (self.signature_threshold.deconstruct() as u128)
            / 1_000_000;
        
        if (message.signatures.len() as u128) < required_sigs {
            return Err(Error::InsufficientSignatures);
        }
        
        // Check 3: Verify each signature
        let mut valid_sigs = 0;
        for sig in &message.signatures {
            if Self::verify_signature(&msg_hash, sig, validators)? {
                valid_sigs += 1;
            }
        }
        
        if (valid_sigs as u128) < required_sigs {
            return Err(Error::InvalidSignatures);
        }
        
        // Mark as processed
        self.processed_messages.insert(msg_hash, current_block());
        
        Ok(true)
    }
    
    /// Verify individual validator signature
    fn verify_signature(
        message_hash: &MessageHash,
        signature: &ValidatorSignature,
        validators: &[ValidatorPublicKey],
    ) -> Result<bool, Error> {
        // Check signer is in validator set
        if !validators.contains(&signature.public_key) {
            return Ok(false);
        }
        
        // Verify cryptographic signature
        let valid = sp_io::crypto::sr25519_verify(
            &signature.signature,
            message_hash.as_ref(),
            &signature.public_key,
        );
        
        Ok(valid)
    }
}

MEV Protection

/// Prevent front-running and sandwich attacks
pub struct MEVProtection {
    // Transaction ordering commitment
    pub commit_reveal_scheme: CommitRevealScheme,
    
    // Fair sequencing service
    pub sequencer: FairSequencer,
}

pub struct CommitRevealScheme {
    pub commitments: HashMap<CommitmentHash, Commitment>,
    pub reveal_period: BlockNumber,
}

#[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
pub struct Commitment {
    pub committer: AccountId,
    pub commitment_hash: Hash,
    pub committed_at: BlockNumber,
    pub revealed: bool,
}

impl CommitRevealScheme {
    /// User commits to swap parameters
    pub fn commit(
        &mut self,
        user: AccountId,
        swap_params_hash: Hash,
    ) -> Result<CommitmentHash, Error> {
        let commitment = Commitment {
            committer: user.clone(),
            commitment_hash: swap_params_hash,
            committed_at: current_block(),
            revealed: false,
        };
        
        let commitment_hash = Self::hash_commitment(&commitment);
        self.commitments.insert(commitment_hash, commitment);
        
        Ok(commitment_hash)
    }
    
    /// User reveals actual swap parameters
    pub fn reveal(
        &mut self,
        commitment_hash: CommitmentHash,
        swap_params: SwapParams,
    ) -> Result<(), Error> {
        let mut commitment = self.commitments
            .get(&commitment_hash)
            .ok_or(Error::CommitmentNotFound)?
            .clone();
        
        // Verify reveal period passed
        ensure!(
            current_block() >= commitment.committed_at + self.reveal_period,
            Error::RevealPeriodNotPassed
        );
        
        // Verify hash matches
        let params_hash = Self::hash_params(&swap_params);
        ensure!(
            params_hash == commitment.commitment_hash,
            Error::InvalidReveal
        );
        
        commitment.revealed = true;
        self.commitments.insert(commitment_hash, commitment);
        
        Ok(())
    }
}

/// Fair transaction sequencing
pub struct FairSequencer {
    pub pending_transactions: Vec<PendingSwap>,
    pub ordering_rule: OrderingRule,
}

#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, TypeInfo)]
pub enum OrderingRule {
    /// First-come-first-served
    FCFS,
    
    /// Time-weighted by reputation
    ReputationWeighted,
    
    /// Batch auction (all swaps in block execute at same price)
    BatchAuction,
}

impl FairSequencer {
    /// Order transactions fairly
    pub fn sequence_transactions(
        &mut self,
    ) -> Vec<PendingSwap> {
        match self.ordering_rule {
            OrderingRule::FCFS => {
                // Simple: order by arrival time
                self.pending_transactions.sort_by_key(|tx| tx.received_at);
            }
            
            OrderingRule::ReputationWeighted => {
                // High reputation gets slight priority
                self.pending_transactions.sort_by_key(|tx| {
                    let reputation = Self::get_reputation(&tx.sender).unwrap_or(0);
                    // Combine time and reputation
                    tx.received_at - (reputation / 1000) as BlockNumber
                });
            }
            
            OrderingRule::BatchAuction => {
                // All execute at uniform clearing price
                // No ordering needed - all batched
            }
        }
        
        self.pending_transactions.clone()
    }
}

Formal Verification

// Using formal verification with kani
#[cfg(kani)]
mod verification {
    use super::*;
    
    #[kani::proof]
    fn verify_no_double_spend() {
        let swap_id: Hash = kani::any();
        let secret: Vec<u8> = kani::any();
        
        // Assume valid swap exists
        kani::assume(Swaps::<T>::contains_key(&swap_id));
        
        // First claim
        let result1 = Module::<T>::reveal_secret(
            Origin::signed(participant),
            swap_id,
            secret.clone(),
        );
        
        // Second claim with same secret (should fail)
        let result2 = Module::<T>::reveal_secret(
            Origin::signed(participant),
            swap_id,
            secret,
        );
        
        // Assert: second claim fails
        kani::assert(result2.is_err(), "Double spend prevented");
    }
    
    #[kani::proof]
    fn verify_timelock_safety() {
        let swap_id: Hash = kani::any();
        let current_block: BlockNumber = kani::any();
        
        let swap = Swaps::<T>::get(&swap_id).unwrap();
        
        // If before time lock, refund should fail
        if current_block <= swap.time_lock {
            let result = Module::<T>::refund(
                Origin::signed(swap.initiator),
                swap_id,
            );
            kani::assert(result.is_err(), "Early refund prevented");
        }
        
        // If after time lock and not claimed, refund should succeed
        if current_block > swap.time_lock && swap.state == SwapState::Initiated {
            let result = Module::<T>::refund(
                Origin::signed(swap.initiator),
                swap_id,
            );
            kani::assert(result.is_ok(), "Legitimate refund succeeds");
        }
    }
}

Audit Checklist

# security-audit-checklist.yml

atomic_swap_security:
  reentrancy:
    - ✓ All external calls after state changes
    - ✓ Reentrancy guards on critical functions
    - ✓ No callback hooks without protection
  
  time_lock:
    - ✓ Minimum time lock enforced
    - ✓ Maximum time lock enforced
    - ✓ Time lock checked before actions
    - ✓ Block timestamp manipulation considered
  
  replay_protection:
    - ✓ Nonces tracked per account
    - ✓ Used secrets recorded
    - ✓ Chain ID included in swap hash
    - ✓ Swap IDs globally unique
  
  collateral:
    - ✓ Sufficient collateral verified
    - ✓ Collateral properly locked
    - ✓ Collateral returned on completion
    - ✓ Slashing conditions enforced
  
  state_machine:
    - ✓ Invalid transitions prevented
    - ✓ All states have exit conditions
    - ✓ State changes atomic
    - ✓ No race conditions

oracle_security:
  data_integrity:
    - ✓ Multiple oracle sources required
    - ✓ Outlier detection implemented
    - ✓ Reputation-weighted consensus
    - ✓ Data signed by oracles
  
  manipulation_resistance:
    - ✓ Stake requirements for oracles
    - ✓ Slashing for bad data
    - ✓ Time-weighted data averaging
    - ✓ Cross-validation between sources

cross_chain:
  message_verification:
    - ✓ Validator signatures verified
    - ✓ Threshold signatures required
    - ✓ Message replay prevented
    - ✓ Chain ID validation
  
  finality:
    - ✓ Source chain finality confirmed
    - ✓ Reorg protection implemented
    - ✓ Timeout handling defined
    - ✓ Dispute resolution process

emergency:
  circuit_breakers:
    - ✓ Emergency pause function
    - ✓ Rate limiting on swaps
    - ✓ Max transaction size limits
    - ✓ Governance override capability
  
  upgrade_safety:
    - ✓ Time-locked upgrades
    - ✓ Multi-sig governance
    - ✓ Migration path defined
    - ✓ Rollback procedure documented

Integration Example

Putting it all together:

/// Complete bridge transaction with all security features
pub async fn execute_secure_bridge_transaction(
    user: AccountId,
    credit: ContributionCredit,
    target_amount: Balance,
    target_currency: BricsCurrency,
) -> Result<BridgeReceipt, Error> {
    
    // 1. Generate ZK proof (Path 2)
    let zk_proof = CreditProofGenerator::prove_credit_capacity(
        &mut rng,
        credit.reputation_score,
        extract_ecological_metrics(&credit),
        target_amount,
    )?;
    
    // 2. Check liquidity (Path 3)
    let liquidity_state = LiquidityPool::check_availability(
        target_currency,
        target_amount,
    ).await?;
    
    ensure!(
        liquidity_state.sufficient,
        Error::InsufficientLiquidity
    );
    
    // 3. Calculate dynamic fee (Path 3)
    let fee = AdaptiveFeeController::calculate_fee(
        liquidity_state.utilization_rate,
    )?;
    
    // 4. Initiate secure atomic swap (Path 4)
    let secret = generate_secret();
    let hash_lock = hash(&secret);
    
    let swap_id = AtomicSwapPallet::initiate_swap(
        user.clone(),
        brics_bridge_account,
        hash_lock,
        time_lock,
        target_amount,
        calculate_brics_equivalent(target_amount, target_currency),
        target_currency,
        calculate_collateral(target_amount),
    )?;
    
    // 5. Wait for BRICS Pay settlement
    let brics_tx = wait_for_brics_settlement(swap_id).await?;
    
    // 6. Reveal secret to claim
    AtomicSwapPallet::reveal_secret(
        brics_bridge_account,
        swap_id,
        secret,
    )?;
    
    // 7. Update reputation (Path 1 & 3)
    ReputationSystem::credit_successful_swap(&user)?;
    
    Ok(BridgeReceipt {
        swap_id,
        user,
        amount: target_amount,
        fee,
        brics_tx_id: brics_tx.id,
        completed_at: current_block(),
    })
}

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