Initial commit: OnionCoin prototype with Proof-of-Relay consensusHEADv0.1.0main

OnionCoin is a privacy cryptocurrency that rewards Tor relay operators
through a unique Proof-of-Contribution consensus mechanism.

Core Features:
- Proof-of-Relay: 30% of block rewards go to Tor operators
- Native .onion node identity (no IP exposure)
- Temporal obfuscation protocols
- Dandelion++ over Tor propagation
- Native inheritance system with dead man's switch

Technical Stack:
- Rust workspace with 8 crates
- Ed25519/X25519 cryptography
- arti (Rust Tor client) integration planned
- 10 minute block time, 5-10 TPS design

Status: Prototype
- Consensus logic complete with passing tests (30/33)
- Network layer conceptual design complete
- Tor integration pending
- Testnet launch planned Q3 2026

License: MIT
Author: Gabriele Salati (virebent)
Contact: g48rix@gmail.com
Website: https://www.gabrielesalati.eu
Repository: https://git.virebent.art/virebent/onioncoin

7 files changed, 2288 insertions, 0 deletions

diff --git a/consensus/src/genesis.rs b/consensus/src/genesis.rs
new file mode 100644
index 0000000..f30f29e
--- /dev/null
+++ b/consensus/src/genesis.rs
@@ -0,0 +1,369 @@
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+/// Genesis mining: fair launch system for OnionCoin
+/// Phase 1 (first 6 months): Earn ONC by running Tor relays
+/// No pre-mine, no ICO, completely fair distribution
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct GenesisMining {
+    /// Genesis phase configuration
+    config: GenesisConfig,
+
+    /// Registered relay nodes
+    relay_nodes: HashMap<[u8; 32], RelayNode>,
+
+    /// Start time of genesis phase
+    start_time: i64,
+
+    /// Total ONC distributed so far
+    total_distributed: u64,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct GenesisConfig {
+    /// Duration of genesis phase (seconds)
+    /// Default: 6 months = 15,552,000 seconds
+    pub duration_seconds: i64,
+
+    /// Total ONC to distribute in genesis phase
+    /// Default: 1,000,000 ONC (fair initial distribution)
+    pub total_genesis_supply: u64,
+
+    /// Minimum relay activity to qualify (bytes)
+    /// Default: 1 GB
+    pub min_relay_bytes: u64,
+
+    /// Bonus multiplier for early participants
+    /// First month: 2x, decreases linearly to 1x
+    pub early_bird_multiplier: bool,
+}
+
+impl Default for GenesisConfig {
+    fn default() -> Self {
+        Self {
+            duration_seconds: 6 * 30 * 24 * 3600, // ~6 months
+            total_genesis_supply: 1_000_000,       // 1M ONC
+            min_relay_bytes: 1024 * 1024 * 1024,   // 1 GB
+            early_bird_multiplier: true,
+        }
+    }
+}
+
+impl GenesisMining {
+    pub fn new(config: GenesisConfig, start_time: i64) -> Self {
+        Self {
+            config,
+            relay_nodes: HashMap::new(),
+            start_time,
+            total_distributed: 0,
+        }
+    }
+
+    /// Register a relay node for genesis mining
+    pub fn register_relay(&mut self, pubkey: [u8; 32], onion_address: String, current_time: i64) {
+        if !self.is_active(current_time) {
+            return;
+        }
+
+        self.relay_nodes.entry(pubkey).or_insert_with(|| RelayNode {
+            pubkey,
+            onion_address,
+            registration_time: current_time,
+            total_bytes_relayed: 0,
+            total_uptime_seconds: 0,
+            rewards_earned: 0,
+        });
+    }
+
+    /// Record relay activity
+    pub fn record_relay_activity(
+        &mut self,
+        pubkey: &[u8; 32],
+        bytes_relayed: u64,
+        uptime_seconds: u64,
+    ) {
+        if let Some(node) = self.relay_nodes.get_mut(pubkey) {
+            node.total_bytes_relayed += bytes_relayed;
+            node.total_uptime_seconds += uptime_seconds;
+        }
+    }
+
+    /// Calculate rewards for a relay node
+    pub fn calculate_rewards(&self, pubkey: &[u8; 32], current_time: i64) -> u64 {
+        let node = match self.relay_nodes.get(pubkey) {
+            Some(n) => n,
+            None => return 0,
+        };
+
+        // Must meet minimum requirement
+        if node.total_bytes_relayed < self.config.min_relay_bytes {
+            return 0;
+        }
+
+        // Base reward proportional to relay work
+        let total_relay_work: u64 = self
+            .relay_nodes
+            .values()
+            .map(|n| n.total_bytes_relayed)
+            .sum();
+
+        if total_relay_work == 0 {
+            return 0;
+        }
+
+        let base_reward = (self.config.total_genesis_supply as f64
+            * (node.total_bytes_relayed as f64 / total_relay_work as f64))
+            as u64;
+
+        // Early bird bonus
+        let multiplier = if self.config.early_bird_multiplier {
+            self.early_bird_multiplier(node.registration_time, current_time)
+        } else {
+            1.0
+        };
+
+        // Uptime bonus (up to 20% extra)
+        let uptime_bonus = self.uptime_bonus(node);
+
+        ((base_reward as f64) * multiplier * (1.0 + uptime_bonus)) as u64
+    }
+
+    /// Early bird multiplier: 2x for first month, linear decay to 1x
+    fn early_bird_multiplier(&self, registration_time: i64, _current_time: i64) -> f64 {
+        let elapsed_since_genesis = registration_time - self.start_time;
+        let one_month = 30 * 24 * 3600;
+
+        if elapsed_since_genesis < 0 {
+            return 2.0; // Registered before/at genesis
+        }
+
+        if elapsed_since_genesis >= one_month {
+            return 1.0; // After first month
+        }
+
+        // Linear decay: 2.0 -> 1.0 over first month
+        2.0 - (elapsed_since_genesis as f64 / one_month as f64)
+    }
+
+    /// Uptime bonus: up to 20% for 99%+ uptime
+    fn uptime_bonus(&self, node: &RelayNode) -> f64 {
+        let total_possible_uptime = chrono::Utc::now().timestamp() - node.registration_time;
+
+        if total_possible_uptime <= 0 {
+            return 0.0;
+        }
+
+        let uptime_ratio = node.total_uptime_seconds as f64 / total_possible_uptime as f64;
+
+        if uptime_ratio >= 0.99 {
+            0.20 // 20% bonus
+        } else if uptime_ratio >= 0.95 {
+            0.10 // 10% bonus
+        } else if uptime_ratio >= 0.90 {
+            0.05 // 5% bonus
+        } else {
+            0.0
+        }
+    }
+
+    /// Distribute rewards to all qualifying nodes
+    pub fn distribute_rewards(&mut self, current_time: i64) -> HashMap<[u8; 32], u64> {
+        let mut rewards = HashMap::new();
+
+        for pubkey in self.relay_nodes.keys().copied().collect::<Vec<_>>() {
+            let reward = self.calculate_rewards(&pubkey, current_time);
+
+            if reward > 0 {
+                if let Some(node) = self.relay_nodes.get_mut(&pubkey) {
+                    node.rewards_earned = reward;
+                    self.total_distributed += reward;
+                }
+                rewards.insert(pubkey, reward);
+            }
+        }
+
+        rewards
+    }
+
+    /// Check if genesis phase is still active
+    pub fn is_active(&self, current_time: i64) -> bool {
+        let elapsed = current_time - self.start_time;
+        elapsed >= 0 && elapsed < self.config.duration_seconds
+    }
+
+    /// Get phase progress (0.0 - 1.0)
+    pub fn progress(&self, current_time: i64) -> f64 {
+        let elapsed = (current_time - self.start_time).max(0);
+        let progress = elapsed as f64 / self.config.duration_seconds as f64;
+        progress.clamp(0.0, 1.0)
+    }
+
+    /// Get leaderboard of top relay nodes
+    pub fn leaderboard(&self, limit: usize) -> Vec<(&RelayNode, u64)> {
+        let mut nodes: Vec<_> = self
+            .relay_nodes
+            .values()
+            .map(|node| {
+                let reward = self.calculate_rewards(&node.pubkey, chrono::Utc::now().timestamp());
+                (node, reward)
+            })
+            .collect();
+
+        nodes.sort_by(|a, b| b.1.cmp(&a.1));
+        nodes.into_iter().take(limit).collect()
+    }
+
+    /// Get statistics
+    pub fn stats(&self) -> GenesisStats {
+        GenesisStats {
+            total_relay_nodes: self.relay_nodes.len(),
+            total_bytes_relayed: self.relay_nodes.values().map(|n| n.total_bytes_relayed).sum(),
+            total_distributed: self.total_distributed,
+            remaining_supply: self.config.total_genesis_supply.saturating_sub(self.total_distributed),
+        }
+    }
+}
+
+/// A relay node participating in genesis mining
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct RelayNode {
+    pub pubkey: [u8; 32],
+    pub onion_address: String,
+    pub registration_time: i64,
+    pub total_bytes_relayed: u64,
+    pub total_uptime_seconds: u64,
+    pub rewards_earned: u64,
+}
+
+/// Statistics about genesis mining
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct GenesisStats {
+    pub total_relay_nodes: usize,
+    pub total_bytes_relayed: u64,
+    pub total_distributed: u64,
+    pub remaining_supply: u64,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_genesis_mining_registration() {
+        let config = GenesisConfig::default();
+        let mut genesis = GenesisMining::new(config, 0);
+
+        genesis.register_relay([1u8; 32], "test1.onion".to_string(), 0);
+        genesis.register_relay([2u8; 32], "test2.onion".to_string(), 100);
+
+        assert_eq!(genesis.relay_nodes.len(), 2);
+    }
+
+    #[test]
+    fn test_relay_activity_recording() {
+        let config = GenesisConfig::default();
+        let mut genesis = GenesisMining::new(config, 0);
+
+        genesis.register_relay([1u8; 32], "test.onion".to_string(), 0);
+        genesis.record_relay_activity(&[1u8; 32], 1_000_000_000, 3600);
+
+        let node = genesis.relay_nodes.get(&[1u8; 32]).unwrap();
+        assert_eq!(node.total_bytes_relayed, 1_000_000_000);
+        assert_eq!(node.total_uptime_seconds, 3600);
+    }
+
+    #[test]
+    fn test_reward_calculation() {
+        let config = GenesisConfig::default();
+        let mut genesis = GenesisMining::new(config, 0);
+
+        // Node 1: 50% of relay work
+        genesis.register_relay([1u8; 32], "test1.onion".to_string(), 0);
+        genesis.record_relay_activity(&[1u8; 32], 50 * 1024 * 1024 * 1024, 86400);
+
+        // Node 2: 50% of relay work
+        genesis.register_relay([2u8; 32], "test2.onion".to_string(), 0);
+        genesis.record_relay_activity(&[2u8; 32], 50 * 1024 * 1024 * 1024, 86400);
+
+        let reward1 = genesis.calculate_rewards(&[1u8; 32], 100);
+        let reward2 = genesis.calculate_rewards(&[2u8; 32], 100);
+
+        // Should get roughly equal rewards (both ~50% of total)
+        assert!(reward1 > 400_000 && reward1 < 600_000);
+        assert!(reward2 > 400_000 && reward2 < 600_000);
+    }
+
+    #[test]
+    fn test_early_bird_bonus() {
+        let config = GenesisConfig::default();
+        let genesis = GenesisMining::new(config, 0);
+
+        // Registered at genesis
+        let multiplier_early = genesis.early_bird_multiplier(0, 100);
+        assert_eq!(multiplier_early, 2.0);
+
+        // Registered after 1 month
+        let one_month = 30 * 24 * 3600;
+        let multiplier_late = genesis.early_bird_multiplier(one_month, one_month + 100);
+        assert_eq!(multiplier_late, 1.0);
+
+        // Registered mid-month
+        let multiplier_mid = genesis.early_bird_multiplier(one_month / 2, one_month / 2 + 100);
+        assert!(multiplier_mid > 1.0 && multiplier_mid < 2.0);
+    }
+
+    #[test]
+    fn test_minimum_relay_requirement() {
+        let config = GenesisConfig::default();
+        let mut genesis = GenesisMining::new(config, 0);
+
+        genesis.register_relay([1u8; 32], "test.onion".to_string(), 0);
+
+        // Below minimum
+        genesis.record_relay_activity(&[1u8; 32], 1_000_000, 3600);
+        let reward = genesis.calculate_rewards(&[1u8; 32], 100);
+        assert_eq!(reward, 0);
+
+        // Above minimum
+        genesis.record_relay_activity(&[1u8; 32], 2 * 1024 * 1024 * 1024, 3600);
+        let reward = genesis.calculate_rewards(&[1u8; 32], 100);
+        assert!(reward > 0);
+    }
+
+    #[test]
+    fn test_phase_progress() {
+        let config = GenesisConfig::default();
+        let genesis = GenesisMining::new(config.clone(), 0);
+
+        assert_eq!(genesis.progress(0), 0.0);
+
+        let half_duration = config.duration_seconds / 2;
+        let mid_progress = genesis.progress(half_duration);
+        assert!((mid_progress - 0.5).abs() < 0.01);
+
+        let end_progress = genesis.progress(config.duration_seconds);
+        assert_eq!(end_progress, 1.0);
+    }
+
+    #[test]
+    fn test_leaderboard() {
+        let config = GenesisConfig::default();
+        let mut genesis = GenesisMining::new(config, 0);
+
+        // Register 3 nodes with different relay amounts
+        genesis.register_relay([1u8; 32], "test1.onion".to_string(), 0);
+        genesis.record_relay_activity(&[1u8; 32], 100 * 1024 * 1024 * 1024, 86400);
+
+        genesis.register_relay([2u8; 32], "test2.onion".to_string(), 0);
+        genesis.record_relay_activity(&[2u8; 32], 50 * 1024 * 1024 * 1024, 86400);
+
+        genesis.register_relay([3u8; 32], "test3.onion".to_string(), 0);
+        genesis.record_relay_activity(&[3u8; 32], 25 * 1024 * 1024 * 1024, 86400);
+
+        let leaderboard = genesis.leaderboard(3);
+
+        assert_eq!(leaderboard.len(), 3);
+        assert_eq!(leaderboard[0].0.pubkey, [1u8; 32]); // Top relay
+        assert!(leaderboard[0].1 > leaderboard[1].1); // Top has higher reward
+    }
+}
diff --git a/consensus/src/lib.rs b/consensus/src/lib.rs
new file mode 100644
index 0000000..80b8bd5
--- /dev/null
+++ b/consensus/src/lib.rs
@@ -0,0 +1,13 @@
+pub mod proof_of_contribution;
+pub mod validator;
+pub mod relay_proof;
+pub mod metrics;
+pub mod selection;
+pub mod genesis;
+
+pub use proof_of_contribution::{ProofOfContribution, ContributionScore, ScoreWeights};
+pub use validator::{Validator, ValidatorTier, ValidatorRegistry};
+pub use relay_proof::{RelayProof, RelayMetrics};
+pub use metrics::{BandwidthMetrics, UptimeMetrics, StorageMetrics};
+pub use selection::{ValidatorSelector, SelectionAlgorithm};
+pub use genesis::{GenesisMining, GenesisConfig};
diff --git a/consensus/src/metrics.rs b/consensus/src/metrics.rs
new file mode 100644
index 0000000..68da6ad
--- /dev/null
+++ b/consensus/src/metrics.rs
@@ -0,0 +1,388 @@
+use serde::{Deserialize, Serialize};
+use std::collections::VecDeque;
+
+/// Tracks bandwidth metrics for a validator
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct BandwidthMetrics {
+    /// Total bytes sent
+    pub bytes_sent: u64,
+
+    /// Total bytes received
+    pub bytes_received: u64,
+
+    /// Peak bandwidth (bytes/second)
+    pub peak_bandwidth: u64,
+
+    /// Average bandwidth (bytes/second)
+    pub avg_bandwidth: u64,
+
+    /// Measurement period (seconds)
+    pub measurement_period: u64,
+}
+
+impl BandwidthMetrics {
+    pub fn new() -> Self {
+        Self {
+            bytes_sent: 0,
+            bytes_received: 0,
+            peak_bandwidth: 0,
+            avg_bandwidth: 0,
+            measurement_period: 0,
+        }
+    }
+
+    /// Total bandwidth (sent + received)
+    pub fn total_bytes(&self) -> u64 {
+        self.bytes_sent + self.bytes_received
+    }
+
+    /// Calculate bandwidth score (normalized 0.0 - 1.0)
+    /// 1 Mbps = 125 KB/s = baseline score of 0.5
+    pub fn score(&self) -> f64 {
+        if self.measurement_period == 0 {
+            return 0.0;
+        }
+
+        let bytes_per_sec = self.total_bytes() / self.measurement_period;
+
+        // Baseline: 125 KB/s (1 Mbps) = 0.5 score
+        // 10 Mbps = 1.0 score
+        const MAX_BYTES_PER_SEC: u64 = 1_250_000; // 10 Mbps
+
+        let score = bytes_per_sec as f64 / MAX_BYTES_PER_SEC as f64;
+
+        score.clamp(0.0, 1.0)
+    }
+
+    /// Update metrics with new measurement
+    pub fn update(&mut self, bytes_sent: u64, bytes_received: u64, period_secs: u64) {
+        self.bytes_sent += bytes_sent;
+        self.bytes_received += bytes_received;
+        self.measurement_period += period_secs;
+
+        if period_secs > 0 {
+            let current_bandwidth = (bytes_sent + bytes_received) / period_secs;
+            self.peak_bandwidth = self.peak_bandwidth.max(current_bandwidth);
+
+            // Update rolling average
+            let total = self.total_bytes();
+            self.avg_bandwidth = total / self.measurement_period;
+        }
+    }
+}
+
+impl Default for BandwidthMetrics {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// Tracks uptime metrics for a validator
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct UptimeMetrics {
+    /// Total uptime in seconds
+    pub total_uptime: u64,
+
+    /// Total time window (seconds)
+    pub total_time: u64,
+
+    /// Number of disconnections
+    pub disconnections: u32,
+
+    /// Longest continuous uptime (seconds)
+    pub longest_uptime: u64,
+
+    /// Current uptime streak (seconds)
+    pub current_streak: u64,
+
+    /// Last seen timestamp
+    pub last_seen: i64,
+}
+
+impl UptimeMetrics {
+    pub fn new(current_time: i64) -> Self {
+        Self {
+            total_uptime: 0,
+            total_time: 0,
+            disconnections: 0,
+            longest_uptime: 0,
+            current_streak: 0,
+            last_seen: current_time,
+        }
+    }
+
+    /// Calculate uptime percentage
+    pub fn uptime_percentage(&self) -> f64 {
+        if self.total_time == 0 {
+            return 0.0;
+        }
+
+        (self.total_uptime as f64 / self.total_time as f64) * 100.0
+    }
+
+    /// Calculate uptime score (0.0 - 1.0)
+    /// Factors: uptime %, disconnection rate, streak length
+    pub fn score(&self) -> f64 {
+        let uptime_score = self.uptime_percentage() / 100.0;
+
+        // Penalty for frequent disconnections
+        let disconnection_penalty = if self.total_time > 0 {
+            let disconnects_per_day =
+                (self.disconnections as f64) / (self.total_time as f64 / 86400.0);
+
+            // More than 5 disconnects/day = penalty
+            if disconnects_per_day > 5.0 {
+                0.5
+            } else if disconnects_per_day > 2.0 {
+                0.8
+            } else {
+                1.0
+            }
+        } else {
+            1.0
+        };
+
+        // Bonus for long streaks
+        let streak_bonus = if self.current_streak > 7 * 86400 {
+            // > 7 days
+            1.2
+        } else if self.current_streak > 24 * 3600 {
+            // > 24 hours
+            1.1
+        } else {
+            1.0
+        };
+
+        (uptime_score * disconnection_penalty * streak_bonus).clamp(0.0, 1.0)
+    }
+
+    /// Record heartbeat (node is online)
+    pub fn record_heartbeat(&mut self, current_time: i64) {
+        let elapsed = (current_time - self.last_seen).max(0) as u64;
+
+        // If gap is small (< 5 min), consider continuous
+        if elapsed < 300 {
+            self.total_uptime += elapsed;
+            self.current_streak += elapsed;
+
+            if self.current_streak > self.longest_uptime {
+                self.longest_uptime = self.current_streak;
+            }
+        } else {
+            // Disconnection detected
+            self.disconnections += 1;
+            self.current_streak = 0;
+        }
+
+        self.total_time += elapsed;
+        self.last_seen = current_time;
+    }
+
+    /// Record explicit disconnection
+    pub fn record_disconnection(&mut self, current_time: i64) {
+        self.disconnections += 1;
+        self.current_streak = 0;
+        self.last_seen = current_time;
+    }
+}
+
+/// Tracks storage contribution metrics
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct StorageMetrics {
+    /// Storage space provided (bytes)
+    pub storage_provided: u64,
+
+    /// Storage actually used (bytes)
+    pub storage_used: u64,
+
+    /// Number of blocks stored
+    pub blocks_stored: u64,
+
+    /// Number of transactions stored
+    pub transactions_stored: u64,
+}
+
+impl StorageMetrics {
+    pub fn new() -> Self {
+        Self {
+            storage_provided: 0,
+            storage_used: 0,
+            blocks_stored: 0,
+            transactions_stored: 0,
+        }
+    }
+
+    /// Calculate utilization percentage
+    pub fn utilization(&self) -> f64 {
+        if self.storage_provided == 0 {
+            return 0.0;
+        }
+
+        (self.storage_used as f64 / self.storage_provided as f64) * 100.0
+    }
+
+    /// Calculate storage score (0.0 - 1.0)
+    /// 10 GB provided = baseline 0.5
+    /// 100 GB provided = 1.0
+    pub fn score(&self) -> f64 {
+        const MAX_GB: u64 = 100;
+
+        let gb_provided = self.storage_provided / (1024 * 1024 * 1024);
+
+        let score = gb_provided as f64 / MAX_GB as f64;
+
+        score.clamp(0.0, 1.0)
+    }
+
+    /// Update storage metrics
+    pub fn update(&mut self, provided: u64, used: u64, blocks: u64, txs: u64) {
+        self.storage_provided = provided;
+        self.storage_used = used;
+        self.blocks_stored = blocks;
+        self.transactions_stored = txs;
+    }
+}
+
+impl Default for StorageMetrics {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// Combined metrics tracker for a validator
+#[derive(Debug)]
+pub struct MetricsTracker {
+    pub bandwidth: BandwidthMetrics,
+    pub uptime: UptimeMetrics,
+    pub storage: StorageMetrics,
+
+    /// History of bandwidth measurements
+    bandwidth_history: VecDeque<BandwidthMetrics>,
+
+    /// Maximum history entries to keep
+    max_history: usize,
+}
+
+impl MetricsTracker {
+    pub fn new(current_time: i64) -> Self {
+        Self {
+            bandwidth: BandwidthMetrics::new(),
+            uptime: UptimeMetrics::new(current_time),
+            storage: StorageMetrics::new(),
+            bandwidth_history: VecDeque::new(),
+            max_history: 24, // 24 hours of hourly measurements
+        }
+    }
+
+    /// Record heartbeat
+    pub fn heartbeat(&mut self, current_time: i64) {
+        self.uptime.record_heartbeat(current_time);
+    }
+
+    /// Update bandwidth
+    pub fn update_bandwidth(&mut self, bytes_sent: u64, bytes_received: u64, period_secs: u64) {
+        self.bandwidth.update(bytes_sent, bytes_received, period_secs);
+
+        // Save to history
+        self.bandwidth_history.push_back(self.bandwidth.clone());
+
+        if self.bandwidth_history.len() > self.max_history {
+            self.bandwidth_history.pop_front();
+        }
+    }
+
+    /// Update storage
+    pub fn update_storage(&mut self, provided: u64, used: u64, blocks: u64, txs: u64) {
+        self.storage.update(provided, used, blocks, txs);
+    }
+
+    /// Get average bandwidth score over history
+    pub fn avg_bandwidth_score(&self) -> f64 {
+        if self.bandwidth_history.is_empty() {
+            return self.bandwidth.score();
+        }
+
+        let total: f64 = self.bandwidth_history.iter().map(|b| b.score()).sum();
+
+        total / self.bandwidth_history.len() as f64
+    }
+
+    /// Get combined metrics score
+    pub fn combined_score(&self) -> f64 {
+        let bandwidth_score = self.avg_bandwidth_score();
+        let uptime_score = self.uptime.score();
+        let storage_score = self.storage.score();
+
+        // Weighted average
+        bandwidth_score * 0.4 + uptime_score * 0.4 + storage_score * 0.2
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_bandwidth_metrics() {
+        let mut metrics = BandwidthMetrics::new();
+
+        // 1 MB sent + received over 10 seconds = 100 KB/s
+        metrics.update(500_000, 500_000, 10);
+
+        assert_eq!(metrics.total_bytes(), 1_000_000);
+        assert_eq!(metrics.avg_bandwidth, 100_000);
+    }
+
+    #[test]
+    fn test_uptime_metrics() {
+        let mut metrics = UptimeMetrics::new(0);
+
+        // Record heartbeats every minute for 1 hour
+        for i in 1..=60 {
+            metrics.record_heartbeat(i * 60);
+        }
+
+        assert!(metrics.uptime_percentage() > 99.0);
+        assert_eq!(metrics.disconnections, 0);
+    }
+
+    #[test]
+    fn test_uptime_with_disconnections() {
+        let mut metrics = UptimeMetrics::new(0);
+
+        metrics.record_heartbeat(60); // 1 min
+        metrics.record_heartbeat(120); // 2 min
+        metrics.record_heartbeat(600); // 10 min (gap = disconnection)
+
+        assert_eq!(metrics.disconnections, 1);
+    }
+
+    #[test]
+    fn test_storage_metrics() {
+        let mut metrics = StorageMetrics::new();
+
+        // 50 GB provided, 25 GB used
+        metrics.update(
+            50 * 1024 * 1024 * 1024,
+            25 * 1024 * 1024 * 1024,
+            1000,
+            50000,
+        );
+
+        assert_eq!(metrics.utilization(), 50.0);
+        assert!(metrics.score() > 0.0);
+    }
+
+    #[test]
+    fn test_metrics_tracker() {
+        let mut tracker = MetricsTracker::new(0);
+
+        tracker.heartbeat(60);
+        tracker.update_bandwidth(1_000_000, 1_000_000, 60);
+        tracker.update_storage(10 * 1024 * 1024 * 1024, 5 * 1024 * 1024 * 1024, 100, 1000);
+
+        let score = tracker.combined_score();
+        assert!(score > 0.0);
+        assert!(score <= 1.0);
+    }
+}
diff --git a/consensus/src/proof_of_contribution.rs b/consensus/src/proof_of_contribution.rs
new file mode 100644
index 0000000..f13fe56
--- /dev/null
+++ b/consensus/src/proof_of_contribution.rs
@@ -0,0 +1,340 @@
+use crate::{Validator, RelayProof, BandwidthMetrics, UptimeMetrics, StorageMetrics};
+use serde::{Deserialize, Serialize};
+
+/// Proof-of-Contribution: OnionCoin's unique consensus mechanism
+/// Combines stake + relay work + bandwidth + uptime + storage
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ProofOfContribution {
+    /// Validator public key
+    pub validator_pubkey: [u8; 32],
+
+    /// Contribution score breakdown
+    pub score: ContributionScore,
+
+    /// Timestamp
+    pub timestamp: i64,
+}
+
+impl ProofOfContribution {
+    /// Calculate contribution score for a validator
+    pub fn calculate(
+        validator: &Validator,
+        relay_proof: Option<&RelayProof>,
+        bandwidth: &BandwidthMetrics,
+        uptime: &UptimeMetrics,
+        storage: &StorageMetrics,
+    ) -> Self {
+        let score = ContributionScore::calculate(
+            validator,
+            relay_proof,
+            bandwidth,
+            uptime,
+            storage,
+        );
+
+        Self {
+            validator_pubkey: validator.pubkey,
+            score,
+            timestamp: chrono::Utc::now().timestamp(),
+        }
+    }
+
+    /// Get total weighted score
+    pub fn total_score(&self) -> f64 {
+        self.score.weighted_total()
+    }
+}
+
+/// Breakdown of contribution score components
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ContributionScore {
+    /// Stake component score (0.0 - 1.0)
+    pub stake_score: f64,
+
+    /// Relay work score (0.0 - 1.0)
+    pub relay_score: f64,
+
+    /// Bandwidth score (0.0 - 1.0)
+    pub bandwidth_score: f64,
+
+    /// Uptime score (0.0 - 1.0)
+    pub uptime_score: f64,
+
+    /// Storage score (0.0 - 1.0)
+    pub storage_score: f64,
+
+    /// Weights for each component
+    pub weights: ScoreWeights,
+}
+
+/// Weights for different contribution components
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ScoreWeights {
+    pub stake: f64,
+    pub relay: f64,
+    pub bandwidth: f64,
+    pub uptime: f64,
+    pub storage: f64,
+}
+
+impl Default for ScoreWeights {
+    fn default() -> Self {
+        Self {
+            stake: 0.40,     // 40% - Still important but not dominant
+            relay: 0.30,     // 30% - UNIQUE: Tor relay work
+            bandwidth: 0.15, // 15% - Network contribution
+            uptime: 0.10,    // 10% - Reliability
+            storage: 0.05,   // 5% - Data availability
+        }
+    }
+}
+
+impl ScoreWeights {
+    /// Verify weights sum to 1.0
+    pub fn is_valid(&self) -> bool {
+        let sum = self.stake + self.relay + self.bandwidth + self.uptime + self.storage;
+        (sum - 1.0).abs() < 0.001
+    }
+}
+
+impl ContributionScore {
+    /// Calculate contribution score from validator metrics
+    pub fn calculate(
+        validator: &Validator,
+        relay_proof: Option<&RelayProof>,
+        bandwidth: &BandwidthMetrics,
+        uptime: &UptimeMetrics,
+        storage: &StorageMetrics,
+    ) -> Self {
+        let weights = ScoreWeights::default();
+
+        // 1. Stake score (logarithmic to reduce whale advantage)
+        let stake_score = Self::calculate_stake_score(validator);
+
+        // 2. Relay score (from Proof-of-Relay)
+        let relay_score = Self::calculate_relay_score(relay_proof);
+
+        // 3. Bandwidth score
+        let bandwidth_score = bandwidth.score();
+
+        // 4. Uptime score
+        let uptime_score = uptime.score();
+
+        // 5. Storage score
+        let storage_score = storage.score();
+
+        Self {
+            stake_score,
+            relay_score,
+            bandwidth_score,
+            uptime_score,
+            storage_score,
+            weights,
+        }
+    }
+
+    /// Calculate stake score (logarithmic)
+    /// This prevents whales from dominating
+    fn calculate_stake_score(validator: &Validator) -> f64 {
+        if validator.stake == 0 {
+            return 0.0;
+        }
+
+        // Use log scale to reduce advantage of large stakes
+        // 10 ONC = 0.1, 100 ONC = 0.2, 1000 ONC = 0.3, etc.
+        let log_stake = (validator.stake as f64).log10();
+        let max_log_stake = 5.0; // 100,000 ONC = max score
+
+        // Apply tier multiplier
+        let tier_multiplier = validator.tier.stake_multiplier();
+
+        ((log_stake / max_log_stake) * tier_multiplier).clamp(0.0, 1.0)
+    }
+
+    /// Calculate relay score from relay proof
+    fn calculate_relay_score(relay_proof: Option<&RelayProof>) -> f64 {
+        match relay_proof {
+            Some(proof) => {
+                // Base score from bytes relayed
+                let gb_relayed = proof.metrics.bytes_relayed as f64 / (1024.0 * 1024.0 * 1024.0);
+                let base_score = (gb_relayed / 100.0).clamp(0.0, 0.8); // Max 0.8 from volume
+
+                // Quality multiplier
+                let quality = proof.metrics.quality_score();
+
+                // Circuit diversity bonus
+                let diversity_bonus = if proof.metrics.unique_circuits > 100 {
+                    0.2
+                } else if proof.metrics.unique_circuits > 50 {
+                    0.1
+                } else {
+                    0.0
+                };
+
+                (base_score * quality + diversity_bonus).clamp(0.0, 1.0)
+            }
+            None => 0.0,
+        }
+    }
+
+    /// Calculate weighted total score
+    pub fn weighted_total(&self) -> f64 {
+        self.stake_score * self.weights.stake
+            + self.relay_score * self.weights.relay
+            + self.bandwidth_score * self.weights.bandwidth
+            + self.uptime_score * self.weights.uptime
+            + self.storage_score * self.weights.storage
+    }
+
+    /// Get human-readable breakdown
+    pub fn breakdown(&self) -> String {
+        format!(
+            "Stake: {:.2}×{:.0}% = {:.3}\n\
+             Relay: {:.2}×{:.0}% = {:.3}\n\
+             Bandwidth: {:.2}×{:.0}% = {:.3}\n\
+             Uptime: {:.2}×{:.0}% = {:.3}\n\
+             Storage: {:.2}×{:.0}% = {:.3}\n\
+             ───────────────────────\n\
+             TOTAL: {:.3}",
+            self.stake_score,
+            self.weights.stake * 100.0,
+            self.stake_score * self.weights.stake,
+            self.relay_score,
+            self.weights.relay * 100.0,
+            self.relay_score * self.weights.relay,
+            self.bandwidth_score,
+            self.weights.bandwidth * 100.0,
+            self.bandwidth_score * self.weights.bandwidth,
+            self.uptime_score,
+            self.weights.uptime * 100.0,
+            self.uptime_score * self.weights.uptime,
+            self.storage_score,
+            self.weights.storage * 100.0,
+            self.storage_score * self.weights.storage,
+            self.weighted_total()
+        )
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::RelayMetrics;
+
+    #[test]
+    fn test_score_weights_valid() {
+        let weights = ScoreWeights::default();
+        assert!(weights.is_valid());
+    }
+
+    #[test]
+    fn test_stake_score_logarithmic() {
+        let validator_small = create_test_validator(100); // 100 ONC
+        let validator_large = create_test_validator(10000); // 10,000 ONC
+
+        let score_small = ContributionScore::calculate_stake_score(&validator_small);
+        let score_large = ContributionScore::calculate_stake_score(&validator_large);
+
+        // Large stake should have higher score but not 100x higher
+        assert!(score_large > score_small);
+        assert!(score_large < score_small * 2.0); // Logarithmic dampening
+    }
+
+    #[test]
+    fn test_relay_score() {
+        let mut metrics = RelayMetrics::new();
+        metrics.bytes_relayed = 50 * 1024 * 1024 * 1024; // 50 GB
+        metrics.unique_circuits = 150;
+        metrics.packets_relayed = 1_000_000;
+
+        let proof = RelayProof::new([1u8; 32], 0, 3600, metrics);
+        let score = ContributionScore::calculate_relay_score(Some(&proof));
+
+        assert!(score > 0.0);
+        assert!(score <= 1.0);
+    }
+
+    #[test]
+    fn test_contribution_score_calculation() {
+        let validator = create_test_validator(1000);
+
+        let mut relay_metrics = RelayMetrics::new();
+        relay_metrics.bytes_relayed = 10 * 1024 * 1024 * 1024; // 10 GB
+        relay_metrics.unique_circuits = 50;
+        relay_metrics.packets_relayed = 100_000;
+
+        let relay_proof = RelayProof::new([1u8; 32], 0, 3600, relay_metrics);
+
+        let mut bandwidth = BandwidthMetrics::new();
+        bandwidth.update(1_000_000, 1_000_000, 100);
+
+        let uptime = UptimeMetrics::new(0);
+
+        let mut storage = StorageMetrics::new();
+        storage.update(20 * 1024 * 1024 * 1024, 10 * 1024 * 1024 * 1024, 1000, 10000);
+
+        let score = ContributionScore::calculate(
+            &validator,
+            Some(&relay_proof),
+            &bandwidth,
+            &uptime,
+            &storage,
+        );
+
+        let total = score.weighted_total();
+        assert!(total > 0.0);
+        assert!(total <= 1.0);
+
+        println!("{}", score.breakdown());
+    }
+
+    #[test]
+    fn test_micro_validator_can_compete() {
+        // Micro validator with great relay work
+        let micro = create_test_validator(10); // Only 10 ONC
+        let mut relay_metrics = RelayMetrics::new();
+        relay_metrics.bytes_relayed = 100 * 1024 * 1024 * 1024; // 100 GB relay!
+        relay_metrics.unique_circuits = 200;
+        relay_metrics.packets_relayed = 1_000_000;
+
+        let relay_proof = RelayProof::new([1u8; 32], 0, 3600, relay_metrics);
+
+        let mut bandwidth = BandwidthMetrics::new();
+        bandwidth.update(10_000_000, 10_000_000, 100); // Good bandwidth
+
+        let mut uptime = UptimeMetrics::new(0);
+        for i in 1..=1000 {
+            uptime.record_heartbeat(i * 60); // Great uptime
+        }
+
+        let storage = StorageMetrics::new();
+
+        let micro_score = ContributionScore::calculate(
+            &micro,
+            Some(&relay_proof),
+            &bandwidth,
+            &uptime,
+            &storage,
+        );
+
+        // Power validator with just stake
+        let power = create_test_validator(10000); // 10,000 ONC
+        let power_score = ContributionScore::calculate(
+            &power,
+            None, // No relay work
+            &BandwidthMetrics::new(),
+            &UptimeMetrics::new(0),
+            &StorageMetrics::new(),
+        );
+
+        println!("Micro validator (10 ONC + relay work):\n{}", micro_score.breakdown());
+        println!("\nPower validator (10,000 ONC, no work):\n{}", power_score.breakdown());
+
+        // Micro validator should be competitive!
+        assert!(micro_score.weighted_total() > power_score.weighted_total() * 0.5);
+    }
+
+    fn create_test_validator(stake: u64) -> Validator {
+        Validator::new([1u8; 32], stake, "test.onion".to_string(), 0).unwrap()
+    }
+}
diff --git a/consensus/src/relay_proof.rs b/consensus/src/relay_proof.rs
new file mode 100644
index 0000000..0d55af3
--- /dev/null
+++ b/consensus/src/relay_proof.rs
@@ -0,0 +1,392 @@
+use serde::{Deserialize, Serialize};
+use blake3::Hasher;
+use std::collections::VecDeque;
+
+/// Proof that a validator relayed traffic through Tor for OnionCoin network
+/// This is OnionCoin's UNIQUE feature: earn rewards by being a Tor relay!
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct RelayProof {
+    /// Validator's public key
+    pub validator_pubkey: [u8; 32],
+
+    /// Time period this proof covers (Unix timestamp range)
+    pub period_start: i64,
+    pub period_end: i64,
+
+    /// Metrics for this period
+    pub metrics: RelayMetrics,
+
+    /// Cryptographic proof of relay work
+    /// In production: ZK-SNARK proof of bandwidth relay
+    /// For prototype: hash chain of relayed packet hashes
+    pub proof_data: Vec<u8>,
+
+    /// Signature from validator
+    #[serde(with = "serde_bytes")]
+    pub signature: [u8; 64],
+}
+
+impl RelayProof {
+    /// Standard proof period (1 hour)
+    pub const PROOF_PERIOD_SECONDS: i64 = 3600;
+
+    /// Create a new relay proof
+    pub fn new(
+        validator_pubkey: [u8; 32],
+        period_start: i64,
+        period_end: i64,
+        metrics: RelayMetrics,
+    ) -> Self {
+        // Generate proof data (simplified)
+        let proof_data = Self::generate_proof_data(&metrics);
+
+        Self {
+            validator_pubkey,
+            period_start,
+            period_end,
+            metrics,
+            proof_data,
+            signature: [0u8; 64], // Placeholder
+        }
+    }
+
+    /// Verify relay proof
+    pub fn verify(&self) -> bool {
+        // Check time period is valid
+        if self.period_end <= self.period_start {
+            return false;
+        }
+
+        // Check period is not too long
+        if self.period_end - self.period_start > Self::PROOF_PERIOD_SECONDS * 24 {
+            return false;
+        }
+
+        // Verify metrics are reasonable
+        if !self.metrics.is_valid() {
+            return false;
+        }
+
+        // Verify proof data
+        let expected_proof = Self::generate_proof_data(&self.metrics);
+        if self.proof_data != expected_proof {
+            return false;
+        }
+
+        true
+    }
+
+    /// Generate proof data from metrics
+    fn generate_proof_data(metrics: &RelayMetrics) -> Vec<u8> {
+        let mut hasher = Hasher::new();
+        hasher.update(&metrics.bytes_relayed.to_le_bytes());
+        hasher.update(&metrics.packets_relayed.to_le_bytes());
+        hasher.update(&metrics.unique_circuits.to_le_bytes());
+        hasher.finalize().as_bytes().to_vec()
+    }
+
+    /// Calculate reward for this relay proof
+    pub fn calculate_reward(&self) -> u64 {
+        // Base reward per GB relayed
+        const REWARD_PER_GB: u64 = 1; // 1 ONC per GB
+
+        let gb_relayed = self.metrics.bytes_relayed / (1024 * 1024 * 1024);
+
+        // Bonus for high circuit diversity
+        let circuit_bonus = if self.metrics.unique_circuits > 100 {
+            1.2
+        } else if self.metrics.unique_circuits > 50 {
+            1.1
+        } else {
+            1.0
+        };
+
+        ((gb_relayed * REWARD_PER_GB) as f64 * circuit_bonus) as u64
+    }
+}
+
+/// Metrics about relay activity
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct RelayMetrics {
+    /// Total bytes relayed in this period
+    pub bytes_relayed: u64,
+
+    /// Total packets relayed
+    pub packets_relayed: u64,
+
+    /// Number of unique circuits served
+    pub unique_circuits: u32,
+
+    /// Average latency (milliseconds)
+    pub avg_latency_ms: u32,
+
+    /// Number of failed relay attempts
+    pub failed_relays: u32,
+
+    /// Uptime during this period (seconds)
+    pub uptime_seconds: u64,
+}
+
+impl RelayMetrics {
+    pub fn new() -> Self {
+        Self {
+            bytes_relayed: 0,
+            packets_relayed: 0,
+            unique_circuits: 0,
+            avg_latency_ms: 0,
+            failed_relays: 0,
+            uptime_seconds: 0,
+        }
+    }
+
+    /// Check if metrics are valid (sanity checks)
+    pub fn is_valid(&self) -> bool {
+        // Reasonable bounds
+        if self.bytes_relayed > 1_000_000_000_000 {
+            // > 1 TB
+            return false;
+        }
+
+        if self.packets_relayed > 1_000_000_000 {
+            // > 1B packets
+            return false;
+        }
+
+        if self.avg_latency_ms > 60_000 {
+            // > 1 minute
+            return false;
+        }
+
+        // Packets should roughly match bytes
+        if self.packets_relayed > 0 {
+            let avg_packet_size = self.bytes_relayed / self.packets_relayed;
+            if avg_packet_size < 20 || avg_packet_size > 1_000_000 {
+                // Unrealistic packet size
+                return false;
+            }
+        }
+
+        true
+    }
+
+    /// Calculate quality score (0.0 - 1.0)
+    pub fn quality_score(&self) -> f64 {
+        let mut score = 1.0;
+
+        // Penalty for high latency
+        if self.avg_latency_ms > 5000 {
+            score *= 0.5;
+        } else if self.avg_latency_ms > 2000 {
+            score *= 0.8;
+        }
+
+        // Penalty for failed relays
+        if self.packets_relayed > 0 {
+            let failure_rate = self.failed_relays as f64 / self.packets_relayed as f64;
+            score *= (1.0 - failure_rate).max(0.0);
+        }
+
+        score.clamp(0.0, 1.0)
+    }
+}
+
+impl Default for RelayMetrics {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// Tracks relay activity for a validator over time
+#[derive(Debug)]
+pub struct RelayTracker {
+    /// Validator public key
+    validator_pubkey: [u8; 32],
+
+    /// Current period metrics
+    current_metrics: RelayMetrics,
+
+    /// Period start time
+    period_start: i64,
+
+    /// Historical proofs (last 24 hours)
+    history: VecDeque<RelayProof>,
+}
+
+impl RelayTracker {
+    /// Maximum history to keep (24 hours = 24 proofs)
+    const MAX_HISTORY: usize = 24;
+
+    pub fn new(validator_pubkey: [u8; 32], current_time: i64) -> Self {
+        Self {
+            validator_pubkey,
+            current_metrics: RelayMetrics::new(),
+            period_start: current_time,
+            history: VecDeque::new(),
+        }
+    }
+
+    /// Record relayed bytes
+    pub fn record_relay(&mut self, bytes: u64, latency_ms: u32, success: bool) {
+        self.current_metrics.bytes_relayed += bytes;
+        self.current_metrics.packets_relayed += 1;
+
+        // Update average latency (simple moving average)
+        let total = self.current_metrics.packets_relayed;
+        self.current_metrics.avg_latency_ms =
+            ((self.current_metrics.avg_latency_ms as u64 * (total - 1) + latency_ms as u64)
+                / total) as u32;
+
+        if !success {
+            self.current_metrics.failed_relays += 1;
+        }
+    }
+
+    /// Record a unique circuit
+    pub fn record_circuit(&mut self) {
+        self.current_metrics.unique_circuits += 1;
+    }
+
+    /// Record uptime
+    pub fn record_uptime(&mut self, seconds: u64) {
+        self.current_metrics.uptime_seconds += seconds;
+    }
+
+    /// Finalize current period and generate proof
+    pub fn finalize_period(&mut self, current_time: i64) -> RelayProof {
+        let proof = RelayProof::new(
+            self.validator_pubkey,
+            self.period_start,
+            current_time,
+            self.current_metrics.clone(),
+        );
+
+        // Add to history
+        self.history.push_back(proof.clone());
+
+        // Trim history
+        if self.history.len() > Self::MAX_HISTORY {
+            self.history.pop_front();
+        }
+
+        // Reset for next period
+        self.current_metrics = RelayMetrics::new();
+        self.period_start = current_time;
+
+        proof
+    }
+
+    /// Get total bytes relayed in last 24 hours
+    pub fn get_24h_bytes(&self) -> u64 {
+        self.history
+            .iter()
+            .map(|p| p.metrics.bytes_relayed)
+            .sum::<u64>()
+            + self.current_metrics.bytes_relayed
+    }
+
+    /// Get average quality score over last 24 hours
+    pub fn get_avg_quality(&self) -> f64 {
+        if self.history.is_empty() {
+            return self.current_metrics.quality_score();
+        }
+
+        let total: f64 = self
+            .history
+            .iter()
+            .map(|p| p.metrics.quality_score())
+            .sum();
+
+        total / self.history.len() as f64
+    }
+
+    /// Get current metrics
+    pub fn current_metrics(&self) -> &RelayMetrics {
+        &self.current_metrics
+    }
+
+    /// Get proof history
+    pub fn history(&self) -> &VecDeque<RelayProof> {
+        &self.history
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_relay_metrics_validation() {
+        let mut metrics = RelayMetrics::new();
+        metrics.bytes_relayed = 1_000_000; // 1 MB
+        metrics.packets_relayed = 1000;
+        metrics.avg_latency_ms = 100;
+
+        assert!(metrics.is_valid());
+
+        // Invalid: too many bytes
+        metrics.bytes_relayed = 2_000_000_000_000;
+        assert!(!metrics.is_valid());
+    }
+
+    #[test]
+    fn test_relay_proof_creation() {
+        let pubkey = [1u8; 32];
+        let mut metrics = RelayMetrics::new();
+        metrics.bytes_relayed = 1_000_000_000; // 1 GB
+        metrics.packets_relayed = 10_000;
+        metrics.unique_circuits = 50;
+
+        let proof = RelayProof::new(pubkey, 0, 3600, metrics);
+
+        assert!(proof.verify());
+        assert_eq!(proof.calculate_reward(), 1); // 1 ONC for 1 GB
+    }
+
+    #[test]
+    fn test_relay_tracker() {
+        let pubkey = [1u8; 32];
+        let mut tracker = RelayTracker::new(pubkey, 0);
+
+        // Record some relay activity
+        tracker.record_relay(1000, 100, true);
+        tracker.record_relay(2000, 150, true);
+        tracker.record_circuit();
+
+        assert_eq!(tracker.current_metrics().bytes_relayed, 3000);
+        assert_eq!(tracker.current_metrics().packets_relayed, 2);
+        assert_eq!(tracker.current_metrics().unique_circuits, 1);
+
+        // Finalize period
+        let proof = tracker.finalize_period(3600);
+        assert!(proof.verify());
+        assert_eq!(tracker.history().len(), 1);
+    }
+
+    #[test]
+    fn test_quality_score() {
+        let mut metrics = RelayMetrics::new();
+        metrics.packets_relayed = 100;
+        metrics.failed_relays = 10; // 10% failure rate
+        metrics.avg_latency_ms = 1000;
+
+        let score = metrics.quality_score();
+        assert!(score < 1.0);
+        assert!(score > 0.0);
+    }
+
+    #[test]
+    fn test_reward_calculation() {
+        let pubkey = [1u8; 32];
+
+        // 5 GB relayed with good circuit diversity
+        let mut metrics = RelayMetrics::new();
+        metrics.bytes_relayed = 5 * 1024 * 1024 * 1024;
+        metrics.unique_circuits = 150; // High diversity = bonus
+
+        let proof = RelayProof::new(pubkey, 0, 3600, metrics);
+        let reward = proof.calculate_reward();
+
+        assert!(reward >= 5); // At least 5 ONC base
+        assert!(reward > 5); // Should have bonus
+    }
+}
diff --git a/consensus/src/selection.rs b/consensus/src/selection.rs
new file mode 100644
index 0000000..538acf5
--- /dev/null
+++ b/consensus/src/selection.rs
@@ -0,0 +1,386 @@
+use crate::{Validator, ProofOfContribution};
+use rand::Rng;
+use serde::{Deserialize, Serialize};
+use blake3::Hasher;
+
+/// Algorithm for selecting validators to produce blocks
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub enum SelectionAlgorithm {
+    /// Pure weighted random based on contribution score
+    WeightedRandom,
+
+    /// Combines score with randomness from previous block
+    VerifiableRandom,
+
+    /// Round-robin among top N validators
+    RoundRobin { top_n: usize },
+}
+
+/// Validator selector for Proof-of-Contribution
+pub struct ValidatorSelector {
+    algorithm: SelectionAlgorithm,
+}
+
+impl ValidatorSelector {
+    pub fn new(algorithm: SelectionAlgorithm) -> Self {
+        Self { algorithm }
+    }
+
+    /// Create with default algorithm
+    pub fn default() -> Self {
+        Self::new(SelectionAlgorithm::VerifiableRandom)
+    }
+
+    /// Select a validator to produce the next block
+    pub fn select_validator(
+        &self,
+        candidates: &[(&Validator, ProofOfContribution)],
+        previous_block_hash: &[u8; 32],
+        block_height: u64,
+    ) -> Option<[u8; 32]> {
+        if candidates.is_empty() {
+            return None;
+        }
+
+        match &self.algorithm {
+            SelectionAlgorithm::WeightedRandom => {
+                self.select_weighted_random(candidates)
+            }
+
+            SelectionAlgorithm::VerifiableRandom => {
+                self.select_verifiable_random(candidates, previous_block_hash, block_height)
+            }
+
+            SelectionAlgorithm::RoundRobin { top_n } => {
+                self.select_round_robin(candidates, *top_n, block_height)
+            }
+        }
+    }
+
+    /// Weighted random selection based on contribution score
+    fn select_weighted_random(
+        &self,
+        candidates: &[(&Validator, ProofOfContribution)],
+    ) -> Option<[u8; 32]> {
+        let total_score: f64 = candidates
+            .iter()
+            .map(|(_, poc)| poc.total_score())
+            .sum();
+
+        if total_score == 0.0 {
+            // Fallback to uniform random
+            let mut rng = rand::thread_rng();
+            let idx = rng.gen_range(0..candidates.len());
+            return Some(candidates[idx].0.pubkey);
+        }
+
+        let mut rng = rand::thread_rng();
+        let mut random_point = rng.gen::<f64>() * total_score;
+
+        for (validator, poc) in candidates {
+            random_point -= poc.total_score();
+            if random_point <= 0.0 {
+                return Some(validator.pubkey);
+            }
+        }
+
+        // Fallback (shouldn't happen)
+        Some(candidates[0].0.pubkey)
+    }
+
+    /// Verifiable random selection using previous block hash
+    /// This makes selection deterministic but unpredictable
+    fn select_verifiable_random(
+        &self,
+        candidates: &[(&Validator, ProofOfContribution)],
+        previous_block_hash: &[u8; 32],
+        block_height: u64,
+    ) -> Option<[u8; 32]> {
+        // Generate deterministic but unpredictable random seed
+        let mut hasher = Hasher::new();
+        hasher.update(previous_block_hash);
+        hasher.update(&block_height.to_le_bytes());
+        let seed_bytes = hasher.finalize();
+
+        // Convert to f64 in range [0, 1)
+        let seed = u64::from_le_bytes(seed_bytes.as_bytes()[0..8].try_into().unwrap());
+        let random_value = (seed as f64) / (u64::MAX as f64);
+
+        // Weighted selection using this deterministic random value
+        let total_score: f64 = candidates
+            .iter()
+            .map(|(_, poc)| poc.total_score())
+            .sum();
+
+        if total_score == 0.0 {
+            let idx = (seed as usize) % candidates.len();
+            return Some(candidates[idx].0.pubkey);
+        }
+
+        let mut random_point = random_value * total_score;
+
+        for (validator, poc) in candidates {
+            random_point -= poc.total_score();
+            if random_point <= 0.0 {
+                return Some(validator.pubkey);
+            }
+        }
+
+        Some(candidates[0].0.pubkey)
+    }
+
+    /// Round-robin among top N validators
+    fn select_round_robin(
+        &self,
+        candidates: &[(&Validator, ProofOfContribution)],
+        top_n: usize,
+        block_height: u64,
+    ) -> Option<[u8; 32]> {
+        // Sort by score (descending)
+        let mut sorted: Vec<_> = candidates.to_vec();
+        sorted.sort_by(|a, b| {
+            b.1.total_score()
+                .partial_cmp(&a.1.total_score())
+                .unwrap_or(std::cmp::Ordering::Equal)
+        });
+
+        // Take top N
+        let top_validators: Vec<_> = sorted.into_iter().take(top_n).collect();
+
+        if top_validators.is_empty() {
+            return None;
+        }
+
+        // Round-robin based on block height
+        let idx = (block_height as usize) % top_validators.len();
+        Some(top_validators[idx].0.pubkey)
+    }
+
+    /// Calculate selection probability for a validator
+    pub fn selection_probability(
+        &self,
+        validator_score: f64,
+        total_score: f64,
+    ) -> f64 {
+        if total_score == 0.0 {
+            return 0.0;
+        }
+
+        validator_score / total_score
+    }
+}
+
+/// Selection statistics for transparency
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SelectionStats {
+    /// Number of times selected
+    pub times_selected: u64,
+
+    /// Number of selection rounds participated in
+    pub rounds_participated: u64,
+
+    /// Average contribution score
+    pub avg_score: f64,
+
+    /// Selection probability (%)
+    pub probability: f64,
+}
+
+impl SelectionStats {
+    pub fn new() -> Self {
+        Self {
+            times_selected: 0,
+            rounds_participated: 0,
+            avg_score: 0.0,
+            probability: 0.0,
+        }
+    }
+
+    /// Update stats after selection round
+    pub fn update(&mut self, was_selected: bool, score: f64, probability: f64) {
+        self.rounds_participated += 1;
+
+        if was_selected {
+            self.times_selected += 1;
+        }
+
+        // Update rolling average score
+        let total_rounds = self.rounds_participated as f64;
+        self.avg_score = (self.avg_score * (total_rounds - 1.0) + score) / total_rounds;
+
+        self.probability = probability;
+    }
+
+    /// Actual selection rate
+    pub fn selection_rate(&self) -> f64 {
+        if self.rounds_participated == 0 {
+            return 0.0;
+        }
+
+        (self.times_selected as f64 / self.rounds_participated as f64) * 100.0
+    }
+}
+
+impl Default for SelectionStats {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{ContributionScore, ScoreWeights};
+
+    #[test]
+    fn test_weighted_random_selection() {
+        let selector = ValidatorSelector::new(SelectionAlgorithm::WeightedRandom);
+
+        let candidates = create_test_candidates();
+        let candidates_refs: Vec<(&Validator, ProofOfContribution)> = candidates
+            .iter()
+            .map(|(v, poc)| (v, poc.clone()))
+            .collect();
+        let selected = selector.select_weighted_random(&candidates_refs);
+
+        assert!(selected.is_some());
+
+        // Verify selected validator is in candidates
+        let selected_pubkey = selected.unwrap();
+        assert!(candidates.iter().any(|(v, _)| v.pubkey == selected_pubkey));
+    }
+
+    #[test]
+    fn test_verifiable_random_deterministic() {
+        let selector = ValidatorSelector::new(SelectionAlgorithm::VerifiableRandom);
+        let candidates = create_test_candidates();
+        let candidates_refs: Vec<(&Validator, ProofOfContribution)> = candidates
+            .iter()
+            .map(|(v, poc)| (v, poc.clone()))
+            .collect();
+        let prev_hash = [1u8; 32];
+        let height = 100;
+
+        let selected1 = selector.select_verifiable_random(&candidates_refs, &prev_hash, height);
+        let selected2 = selector.select_verifiable_random(&candidates_refs, &prev_hash, height);
+
+        // Same inputs = same output (deterministic)
+        assert_eq!(selected1, selected2);
+
+        // Different block = different selection
+        let selected3 = selector.select_verifiable_random(&candidates_refs, &prev_hash, height + 1);
+        // Might be same or different, but test passes either way
+        assert!(selected3.is_some());
+    }
+
+    #[test]
+    fn test_round_robin() {
+        let selector = ValidatorSelector::new(SelectionAlgorithm::RoundRobin { top_n: 3 });
+        let candidates = create_test_candidates();
+        let candidates_refs: Vec<(&Validator, ProofOfContribution)> = candidates
+            .iter()
+            .map(|(v, poc)| (v, poc.clone()))
+            .collect();
+
+        let selected1 = selector.select_round_robin(&candidates_refs, 3, 0);
+        let selected2 = selector.select_round_robin(&candidates_refs, 3, 1);
+        let selected3 = selector.select_round_robin(&candidates_refs, 3, 2);
+
+        assert!(selected1.is_some());
+        assert!(selected2.is_some());
+        assert!(selected3.is_some());
+
+        // Should cycle through top validators
+        assert_ne!(selected1, selected2);
+    }
+
+    #[test]
+    fn test_selection_probability() {
+        let selector = ValidatorSelector::default();
+
+        let prob = selector.selection_probability(0.5, 2.0);
+        assert_eq!(prob, 0.25);
+
+        let prob_zero = selector.selection_probability(0.5, 0.0);
+        assert_eq!(prob_zero, 0.0);
+    }
+
+    #[test]
+    fn test_selection_stats() {
+        let mut stats = SelectionStats::new();
+
+        stats.update(true, 0.8, 0.25);
+        stats.update(false, 0.7, 0.20);
+        stats.update(true, 0.9, 0.30);
+
+        assert_eq!(stats.times_selected, 2);
+        assert_eq!(stats.rounds_participated, 3);
+        assert!((stats.avg_score - 0.8).abs() < 0.1);
+        assert!((stats.selection_rate() - 66.67).abs() < 1.0);
+    }
+
+    #[test]
+    fn test_high_score_validator_selected_more() {
+        let selector = ValidatorSelector::new(SelectionAlgorithm::WeightedRandom);
+
+        let high_score_validator = create_test_validator([1u8; 32], 0.9);
+        let low_score_validator = create_test_validator([2u8; 32], 0.1);
+
+        let candidates = vec![
+            (&high_score_validator, create_poc([1u8; 32], 0.9)),
+            (&low_score_validator, create_poc([2u8; 32], 0.1)),
+        ];
+
+        // Run selection many times
+        let mut high_score_count = 0;
+        for _ in 0..1000 {
+            if let Some(selected) = selector.select_weighted_random(&candidates) {
+                if selected == [1u8; 32] {
+                    high_score_count += 1;
+                }
+            }
+        }
+
+        // High score validator should be selected ~90% of time
+        let high_score_rate = high_score_count as f64 / 1000.0;
+        assert!(high_score_rate > 0.85 && high_score_rate < 0.95);
+    }
+
+    fn create_test_candidates() -> Vec<(Validator, ProofOfContribution)> {
+        vec![
+            (
+                create_test_validator([1u8; 32], 0.8),
+                create_poc([1u8; 32], 0.8),
+            ),
+            (
+                create_test_validator([2u8; 32], 0.6),
+                create_poc([2u8; 32], 0.6),
+            ),
+            (
+                create_test_validator([3u8; 32], 0.4),
+                create_poc([3u8; 32], 0.4),
+            ),
+        ]
+    }
+
+    fn create_test_validator(pubkey: [u8; 32], _score: f64) -> Validator {
+        Validator::new(pubkey, 1000, "test.onion".to_string(), 0).unwrap()
+    }
+
+    fn create_poc(pubkey: [u8; 32], total_score: f64) -> ProofOfContribution {
+        let score = ContributionScore {
+            stake_score: total_score * 0.4,
+            relay_score: total_score * 0.3,
+            bandwidth_score: total_score * 0.15,
+            uptime_score: total_score * 0.1,
+            storage_score: total_score * 0.05,
+            weights: ScoreWeights::default(),
+        };
+
+        ProofOfContribution {
+            validator_pubkey: pubkey,
+            score,
+            timestamp: 0,
+        }
+    }
+}
diff --git a/consensus/src/validator.rs b/consensus/src/validator.rs
new file mode 100644
index 0000000..b5c3a70
--- /dev/null
+++ b/consensus/src/validator.rs
@@ -0,0 +1,400 @@
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+/// Validator tier based on stake amount
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub enum ValidatorTier {
+    /// Micro validator: 10 ONC minimum stake
+    /// Perfect for Raspberry Pi Zero, old hardware
+    Micro,
+
+    /// Light validator: 100 ONC minimum stake
+    /// Raspberry Pi 4, basic VPS
+    Light,
+
+    /// Standard validator: 1000 ONC minimum stake
+    /// Desktop PC, decent VPS
+    Standard,
+
+    /// Power validator: 10000 ONC minimum stake
+    /// Dedicated server, 24/7 operation
+    Power,
+}
+
+impl ValidatorTier {
+    /// Get minimum stake required for this tier
+    pub fn min_stake(&self) -> u64 {
+        match self {
+            Self::Micro => 10,
+            Self::Light => 100,
+            Self::Standard => 1000,
+            Self::Power => 10000,
+        }
+    }
+
+    /// Get expected monthly return for this tier (approximate)
+    pub fn expected_monthly_return(&self) -> f64 {
+        match self {
+            Self::Micro => 0.1,
+            Self::Light => 1.0,
+            Self::Standard => 10.0,
+            Self::Power => 100.0,
+        }
+    }
+
+    /// Determine tier from stake amount
+    pub fn from_stake(stake: u64) -> Self {
+        if stake >= 10000 {
+            Self::Power
+        } else if stake >= 1000 {
+            Self::Standard
+        } else if stake >= 100 {
+            Self::Light
+        } else {
+            Self::Micro
+        }
+    }
+
+    /// Get stake weight multiplier for this tier
+    pub fn stake_multiplier(&self) -> f64 {
+        match self {
+            Self::Micro => 1.0,
+            Self::Light => 1.1,    // 10% bonus
+            Self::Standard => 1.2, // 20% bonus
+            Self::Power => 1.3,    // 30% bonus
+        }
+    }
+}
+
+/// A validator in the OnionCoin network
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Validator {
+    /// Validator's public key (also .onion identity)
+    pub pubkey: [u8; 32],
+
+    /// Staked amount
+    pub stake: u64,
+
+    /// Validator tier
+    pub tier: ValidatorTier,
+
+    /// When the stake was created (Unix timestamp)
+    pub stake_time: i64,
+
+    /// Lock period end time (Unix timestamp)
+    pub unlock_time: i64,
+
+    /// Onion address of the validator node
+    pub onion_address: String,
+
+    /// Is currently active?
+    pub active: bool,
+
+    /// Total blocks validated
+    pub blocks_validated: u64,
+
+    /// Total rewards earned
+    pub total_rewards: u64,
+}
+
+impl Validator {
+    /// Minimum lock period for stake (30 days)
+    pub const LOCK_PERIOD_DAYS: i64 = 30;
+
+    /// Create a new validator
+    pub fn new(
+        pubkey: [u8; 32],
+        stake: u64,
+        onion_address: String,
+        current_time: i64,
+    ) -> Result<Self, ValidatorError> {
+        // Check minimum stake
+        if stake < ValidatorTier::Micro.min_stake() {
+            return Err(ValidatorError::InsufficientStake {
+                provided: stake,
+                minimum: ValidatorTier::Micro.min_stake(),
+            });
+        }
+
+        let tier = ValidatorTier::from_stake(stake);
+        let unlock_time = current_time + (Self::LOCK_PERIOD_DAYS * 24 * 3600);
+
+        Ok(Self {
+            pubkey,
+            stake,
+            tier,
+            stake_time: current_time,
+            unlock_time,
+            onion_address,
+            active: true,
+            blocks_validated: 0,
+            total_rewards: 0,
+        })
+    }
+
+    /// Check if stake is locked
+    pub fn is_locked(&self, current_time: i64) -> bool {
+        current_time < self.unlock_time
+    }
+
+    /// Add stake to existing validator
+    pub fn add_stake(&mut self, amount: u64, current_time: i64) {
+        self.stake += amount;
+        self.tier = ValidatorTier::from_stake(self.stake);
+
+        // Extend lock period
+        self.unlock_time = current_time + (Self::LOCK_PERIOD_DAYS * 24 * 3600);
+    }
+
+    /// Remove stake (only if unlocked)
+    pub fn remove_stake(
+        &mut self,
+        amount: u64,
+        current_time: i64,
+    ) -> Result<(), ValidatorError> {
+        if self.is_locked(current_time) {
+            return Err(ValidatorError::StakeLocked {
+                unlock_time: self.unlock_time,
+            });
+        }
+
+        if amount > self.stake {
+            return Err(ValidatorError::InsufficientStake {
+                provided: self.stake,
+                minimum: amount,
+            });
+        }
+
+        self.stake -= amount;
+        self.tier = ValidatorTier::from_stake(self.stake);
+
+        // Deactivate if below minimum
+        if self.stake < ValidatorTier::Micro.min_stake() {
+            self.active = false;
+        }
+
+        Ok(())
+    }
+
+    /// Record a validated block
+    pub fn record_block(&mut self, reward: u64) {
+        self.blocks_validated += 1;
+        self.total_rewards += reward;
+    }
+
+    /// Calculate ROI percentage
+    pub fn roi_percentage(&self) -> f64 {
+        if self.stake == 0 {
+            0.0
+        } else {
+            (self.total_rewards as f64 / self.stake as f64) * 100.0
+        }
+    }
+}
+
+/// Registry of all validators in the network
+#[derive(Debug, Default)]
+pub struct ValidatorRegistry {
+    validators: HashMap<[u8; 32], Validator>,
+}
+
+impl ValidatorRegistry {
+    pub fn new() -> Self {
+        Self {
+            validators: HashMap::new(),
+        }
+    }
+
+    /// Register a new validator
+    pub fn register(&mut self, validator: Validator) -> Result<(), ValidatorError> {
+        if self.validators.contains_key(&validator.pubkey) {
+            return Err(ValidatorError::AlreadyRegistered);
+        }
+
+        self.validators.insert(validator.pubkey, validator);
+        Ok(())
+    }
+
+    /// Get a validator by pubkey
+    pub fn get(&self, pubkey: &[u8; 32]) -> Option<&Validator> {
+        self.validators.get(pubkey)
+    }
+
+    /// Get a mutable validator by pubkey
+    pub fn get_mut(&mut self, pubkey: &[u8; 32]) -> Option<&mut Validator> {
+        self.validators.get_mut(pubkey)
+    }
+
+    /// Get all active validators
+    pub fn get_active(&self) -> Vec<&Validator> {
+        self.validators
+            .values()
+            .filter(|v| v.active)
+            .collect()
+    }
+
+    /// Get validators by tier
+    pub fn get_by_tier(&self, tier: ValidatorTier) -> Vec<&Validator> {
+        self.validators
+            .values()
+            .filter(|v| v.tier == tier && v.active)
+            .collect()
+    }
+
+    /// Total staked amount across all validators
+    pub fn total_staked(&self) -> u64 {
+        self.validators
+            .values()
+            .filter(|v| v.active)
+            .map(|v| v.stake)
+            .sum()
+    }
+
+    /// Count of active validators
+    pub fn active_count(&self) -> usize {
+        self.validators
+            .values()
+            .filter(|v| v.active)
+            .count()
+    }
+
+    /// Count by tier
+    pub fn count_by_tier(&self) -> HashMap<ValidatorTier, usize> {
+        let mut counts = HashMap::new();
+
+        for validator in self.validators.values() {
+            if validator.active {
+                *counts.entry(validator.tier).or_insert(0) += 1;
+            }
+        }
+
+        counts
+    }
+
+    /// Deactivate validator
+    pub fn deactivate(&mut self, pubkey: &[u8; 32]) -> Result<(), ValidatorError> {
+        let validator = self.validators.get_mut(pubkey)
+            .ok_or(ValidatorError::NotFound)?;
+
+        validator.active = false;
+        Ok(())
+    }
+
+    /// Remove validator (only if stake is 0)
+    pub fn remove(&mut self, pubkey: &[u8; 32]) -> Result<(), ValidatorError> {
+        let validator = self.validators.get(pubkey)
+            .ok_or(ValidatorError::NotFound)?;
+
+        if validator.stake > 0 {
+            return Err(ValidatorError::CannotRemoveWithStake);
+        }
+
+        self.validators.remove(pubkey);
+        Ok(())
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ValidatorError {
+    #[error("Insufficient stake: provided {provided}, minimum {minimum}")]
+    InsufficientStake { provided: u64, minimum: u64 },
+
+    #[error("Stake is locked until timestamp {unlock_time}")]
+    StakeLocked { unlock_time: i64 },
+
+    #[error("Validator already registered")]
+    AlreadyRegistered,
+
+    #[error("Validator not found")]
+    NotFound,
+
+    #[error("Cannot remove validator with non-zero stake")]
+    CannotRemoveWithStake,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_validator_tiers() {
+        assert_eq!(ValidatorTier::from_stake(10), ValidatorTier::Micro);
+        assert_eq!(ValidatorTier::from_stake(100), ValidatorTier::Light);
+        assert_eq!(ValidatorTier::from_stake(1000), ValidatorTier::Standard);
+        assert_eq!(ValidatorTier::from_stake(10000), ValidatorTier::Power);
+    }
+
+    #[test]
+    fn test_validator_creation() {
+        let pubkey = [1u8; 32];
+        let validator = Validator::new(
+            pubkey,
+            1000,
+            "test.onion:9333".to_string(),
+            0,
+        ).unwrap();
+
+        assert_eq!(validator.stake, 1000);
+        assert_eq!(validator.tier, ValidatorTier::Standard);
+        assert!(validator.active);
+    }
+
+    #[test]
+    fn test_stake_locking() {
+        let pubkey = [1u8; 32];
+        let mut validator = Validator::new(
+            pubkey,
+            1000,
+            "test.onion:9333".to_string(),
+            0,
+        ).unwrap();
+
+        // Should be locked
+        assert!(validator.is_locked(1000));
+
+        // Should be unlocked after lock period
+        let unlock_time = Validator::LOCK_PERIOD_DAYS * 24 * 3600;
+        assert!(!validator.is_locked(unlock_time + 1));
+
+        // Cannot remove stake while locked
+        assert!(validator.remove_stake(100, 1000).is_err());
+
+        // Can remove stake after unlock
+        assert!(validator.remove_stake(100, unlock_time + 1).is_ok());
+        assert_eq!(validator.stake, 900);
+    }
+
+    #[test]
+    fn test_validator_registry() {
+        let mut registry = ValidatorRegistry::new();
+
+        let validator = Validator::new(
+            [1u8; 32],
+            1000,
+            "test.onion:9333".to_string(),
+            0,
+        ).unwrap();
+
+        registry.register(validator).unwrap();
+
+        assert_eq!(registry.active_count(), 1);
+        assert_eq!(registry.total_staked(), 1000);
+    }
+
+    #[test]
+    fn test_validator_roi() {
+        let mut validator = Validator::new(
+            [1u8; 32],
+            1000,
+            "test.onion:9333".to_string(),
+            0,
+        ).unwrap();
+
+        validator.record_block(5);
+        validator.record_block(5);
+
+        assert_eq!(validator.blocks_validated, 2);
+        assert_eq!(validator.total_rewards, 10);
+        assert_eq!(validator.roi_percentage(), 1.0); // 10/1000 = 1%
+    }
+}