Which should we work on as the unsolved problems in cryptocurrency and why?
Scalability - Increasing transaction processing capacity and speeds on blockchains to support wider adoption. Issues around block size limits, transition to proof-of-stake, sharding, layer 2 solutions.

Privacy - Enhancing privacy protections for users on public blockchains while meeting regulations. Zero knowledge proofs, confidential transactions, mixers/tumblers.

Security - Preventing hacking attacks, thefts, fraud on blockchains themselves as adoption increases. Consensus protocols, key management, formal verification.

Governance - Determining the best mechanisms for protocol upgrades, conflict resolution, user representation for decentralized networks. On-chain voting, off-chain coordination.

Regulation - Clarifying how cryptocurrencies fit into existing regulatory frameworks around securities, commodities, payments. KYC/AML compliance for exchanges.

Volatility - Reducing price swings to be more usable as currency/payments. Stablecoins, reserve-backed currencies, tokenomics.

Energy - Developing sustainable alternatives to energy-intensive proof-of-work mining ascriticism rises. Proof-of-stake, off-chain computing.

Usability - Improving user experiences and interfaces for transacting and managing assets and wallets. Simplified addresses, fiat on-ramps.

Interoperability - Allowing inter-blockchain communication and exchange of value. Cross-chain protocols, atomic swaps, blockchain bridges.

Others - We welcome your own ideas/pain points