Reward Currency Design

Reward Currency Design Analysis

Problem Statement

Different types of rewards should be paid in different currencies based on their purpose:

1. Measurement Rewards: Should be paid in the same O currency as the measurement (e.g., water price in EUR → pay in OEUR)
2. Stabilization Mining Rewards: Should be paid in the same O currency being stabilized (e.g., stabilizing OEUR → pay in OEUR)
3. Traditional Mining (PoW/PoB): Should be in a fixed currency since hardware costs are USD-based globally

Current Implementation Analysis

Traditional Mining Rewards (PoW/PoB)

• Current: Hardcoded as 2,800 OUSD per block
• Rationale: ✅ Correct - Hardware costs are similar in USD worldwide
• Status: Already using OUSD ✓

Measurement Rewards

• Current: Uses generic CAmount reward_amount without currency specification
• Issue: Not currency-aware - all rewards likely paid in same currency
• Need: Should extract currency from measurement and pay in matching O currency

Stabilization Mining Rewards

• Current: Creates rewards for unstable currencies but doesn't specify payment currency
• Issue: Amount stored as CAmount (generic), not currency-specific
• Need: Should pay in the currency being stabilized (e.g., stabilizing OEUR → pay in OEUR)

Proposed Design

1. Traditional Mining Rewards (PoW/PoB)

Decision: Use OUSD

• Rationale: Hardware costs are similar in USD globally
• Implementation: Already correct ✓
• Block Reward: 2,800 OUSD per block
• PoB Reward: 2,240 OUSD per block

2. Measurement Rewards

Decision: Pay in the submitter's birth currency (not the measurement currency)

• Rationale: Users from different countries are invited to submit measurements
• They may submit measurements for currencies different from their birth currency
• Users should be rewarded in their own birth currency for ease of use
• Example: User from Mexico (birth currency OMXN) submits EUR water price → Pay in OMXN
• Implementation: Extract birth currency from user's public key via BrightID database

3. Stabilization Mining Rewards

Decision: Pay in the same O currency being stabilized

• Stabilizing OEUR → Pay recipients in OEUR
• Stabilizing OMXN → Pay recipients in OMXN
• Rationale: Recipients in that currency region can use the reward directly
• Implementation: Use the unstable currency code to create currency-specific rewards

Implementation Status

Completed Changes

1. Traditional Mining (src/consensus/o_rewards.h):

   • ✅ Already using OUSD
   • ✅ Documented rationale (hardware costs in USD globally)

2. Measurement Rewards (src/consensus/measurement_rewards.h):

   • ✅ Added reward_currency field to MeasurementRewardTransaction
   • ✅ Updated serialization to include currency
   • ⏳ TODO: Extract currency from measurement data when creating rewards
   • ⏳ TODO: Convert fiat currency code (USD, EUR) to O currency code (OUSD, OEUR)

3. Stabilization Mining (src/consensus/stabilization_helpers.cpp):

   • ✅ Currency already tracked in unstable_currency field
   • ✅ Added logging to indicate currency being paid
   • ⏳ TODO: Extract currency from measurement data when creating rewards
   • ⏳ TODO: Use multi-currency outputs when fully integrated

Future Work

Multi-Currency Transaction Integration:

• Currently rewards use legacy CTxOut (single currency)
• When multi-currency transactions are fully integrated:
  • Use CMultiCurrencyTxOut for measurement rewards
  • Use CMultiCurrencyTxOut for stabilization rewards
  • Convert currency codes to CurrencyId using CurrencyRegistry::GetCurrencyId()
  • Create outputs with appropriate MultiCurrencyAmount for each currency

Currency Decision Summary

Reward Type	Currency	Rationale
PoW Block Mining	OUSD	Hardware costs are USD-based globally
PoB Block Mining	OUSD	Hardware costs are USD-based globally
Measurement Rewards	Submitter's birth currency	Users from different countries submit measurements; reward them in their own currency
Stabilization Rewards	Same as unstable currency	Reward stabilization in the affected currency

Multi-Currency Transaction Support

O Blockchain already has multi-currency support (CMultiCurrencyTxOut). We need to:

1. Use multi-currency outputs for measurement and stabilization rewards
2. Keep traditional mining rewards in single-currency (OUSD) for simplicity
3. Ensure currency conversion is handled correctly