Goal: Understand what makes Solana especially strong for low-fee, high-throughput apps—and how it compares to other L1s. Cover: Public‑key crypto (ed25519), Proof of History “clock,” Tower BFT, Sealevel parallel runtime, fees & local fee markets; quick contrasts with Ethereum, Avalanche, NEAR. Activity: Fill a one‑page “chain speed & finality” comparison and walk through one Solana vs one Ethereum transaction on explorers. Takeaway: “I can explain—clearly—why Solana’s design gives sub‑second block cadence, parallel execution, and ultra‑low fees for most use cases.”

1) Module overview

Solana’s edge comes from a tight pipeline: cryptographic signatures prove control → Proof of History (PoH) orders events like a global clock → Tower BFT finalizes with stake‑weighted voting → the Sealevel runtime executes many non‑conflicting transactions in parallel → a base fee + priority fee model (with local fee markets) keeps costs low and isolates congestion. For building consumer dApps or running active communities, that means fast UX at tiny cost, even during busy periods.

2) Core talking points

Keys & signatures (Solana specifics)

• A private key makes signatures; a public key lets anyone verify them — this is public‑key cryptography. Most Solana account addresses are ed25519 public keys (base58). Wallets surface “connect / sign message / sign transaction” so you know what you approve. See: How public key cryptography works (Cloudflare)
• Solana exposes native signature‑verification programs (ed25519, secp256k1) that programs can call inside transactions when they need to validate signatures on‑chain. See background on accounts/programs: Core Concepts — Accounts

Ordering with a cryptographic clock (PoH)

• Proof of History is a verifiable, append‑only hash chain that gives everyone the same notion of “time,” so the current leader can pre‑order transactions before consensus messages fly. Less chatter → lower latency. Overview of commitments and timing: Core Concepts

Voting & finality (Tower BFT)

• Tower BFT builds on PoH: validators vote with stake‑weighted lockouts so forks converge quickly. Commitment levels — processed / confirmed / finalized — let apps trade speed for certainty; finalized means supermajority + max lockout (high assurance). See: Transaction Confirmation & Expiration

Parallel execution (Sealevel)

• Unlike single‑threaded runtimes, Sealevel executes transactions in parallel when their account writes don’t overlap. Declaring all read/write accounts up front lets the runtime schedule tons of independent work across cores. Intro to transactions and instruction scheduling: Transactions and Instructions

Fees & local fee markets

• Base fee: 5,000 lamports per signature (half burned, half to the leader). Priority fee: optional micro‑lamports per compute unit to jump the queue when you need faster inclusion. Typical transfers are fractions of a cent. See: Transaction Fees — base and prioritization fees
• Local fee markets: because contention is per‑account, hotspots (e.g., a popular mint) raise fees there while unrelated activity remains cheap — better UX than global fee spikes.

Timing realities