Blockchain Basics Skill Skill

Blockchain Basics Skill

Master blockchain fundamentals including consensus mechanisms, cryptographic primitives, and distributed systems architecture.

Quick Start

# Invoke this skill for blockchain fundamentals
Skill("blockchain-basics", topic="consensus", depth="intermediate")

Topics Covered

1. Consensus Mechanisms

Learn how distributed networks achieve agreement:

Proof of Work: Mining, hashrate, difficulty adjustment
Proof of Stake: Validators, slashing, finality
Byzantine Fault Tolerance: Leader election, view changes

2. Cryptographic Foundations

Understand the security primitives:

Hash Functions: SHA-256, Keccak-256, properties
Digital Signatures: ECDSA, Ed25519, verification
Merkle Trees: Proof construction, verification

3. Network Architecture

Explore distributed systems:

P2P Networks: Gossip protocols, peer discovery
Node Types: Full nodes, light clients, archives
Block Propagation: Compact blocks, relay networks

4. Transaction Lifecycle

Follow data through the chain:

Transaction Structure: Inputs, outputs, signatures
Mempool: Fee markets, ordering, priority
Confirmation: Finality, reorganization

Code Examples

Verify Merkle Proof

import hashlib

def verify_merkle_proof(leaf: bytes, proof: list, root: bytes) -> bool:
    """Verify a Merkle proof for inclusion"""
    current = leaf
    for sibling, is_left in proof:
        if is_left:
            current = hashlib.sha256(sibling + current).digest()
        else:
            current = hashlib.sha256(current + sibling).digest()
    return current == root

Calculate Block Hash

import hashlib
import struct

def calculate_block_hash(header: dict) -> bytes:
    """Calculate Bitcoin-style block hash"""
    data = struct.pack(
        '<I32s32sIII',
        header['version'],
        bytes.fromhex(header['prev_block']),
        bytes.fromhex(header['merkle_root']),
        header['timestamp'],
        header['bits'],
        header['nonce']
    )
    return hashlib.sha256(hashlib.sha256(data).digest()).digest()[::-1]

Common Pitfalls

| Pitfall | Issue | Solution | |---------|-------|----------| | Finality confusion | PoW is probabilistic | Wait for 6+ confirmations | | Hash vs encryption | Hashes are one-way | Use proper encryption for secrets | | Timestamp trust | Miners can manipulate | Use block height for precision |

Troubleshooting

"Why is my transaction not confirming?"

Check transaction fee vs current mempool
Verify nonce is sequential (no gaps)
Ensure sufficient balance for amount + gas

"How do I verify a signature?"

from eth_account import Account
from eth_account.messages import encode_defunct

message = encode_defunct(text="Hello")
address = Account.recover_message(message, signature=sig)

Learning Path

[Beginner] → Hash Functions → Digital Signatures → Transactions
    ↓
[Intermediate] → Merkle Trees → Consensus → Network Layer
    ↓
[Advanced] → BFT Protocols → Sharding → Cross-chain

Test Yourself

# Unit test template
def test_merkle_root():
    txs = [b"tx1", b"tx2", b"tx3", b"tx4"]
    root = build_merkle_root(txs)
    assert len(root) == 32
    assert verify_merkle_proof(txs[0], get_proof(0), root)

Cross-References

Bonded Agent: 01-blockchain-fundamentals
Related Skills: ethereum-development, smart-contract-security

Version History

| Version | Date | Changes | |---------|------|---------| | 2.0.0 | 2025-01 | Production-grade with validation, examples | | 1.0.0 | 2024-12 | Initial release |

Agent Skills: Blockchain Basics Skill

Skill Files