When I started the #100DaysOfSolana challenge, I expected to learn tools and APIs. What I didn’t expect was how quickly my understanding of identity would change.

In Web2, identity = usernames + passwords stored by companies.
On Solana, identity = a cryptographic keypair that you own.

This post breaks that down with real code and what I built in my first 4 days.

🧠 Identity = Keypair (The Core Idea)

Every Solana identity is:

• Public Key → your address (shareable)
• Private Key → your authority (must be protected)

If you’ve used SSH, it’s the same model:

ssh-keygen

You generate:

• id_rsa.pub → public
• id_rsa → private

👉 Solana works the same way—but the entire blockchain verifies you, not just one server.

🚀 Day 1: Creating My Identity (CLI Wallet)

solana-keygen new
solana address
solana balance

This creates a keypair stored at:

~/.config/solana/id.json

👉 Insight:
My entire identity is just a file on disk

💸 Day 2: First Transaction (Ownership in Action)

solana airdrop 1
solana transfer <RECIPIENT_ADDRESS> 0.5

👉 What’s happening under the hood:

• Transaction is signed with my private key
• Network verifies using my public key

⚙️ Day 3: Parsing a Transaction (Programmatic Identity)

I built a script using @solana/kit:

import { createSolanaRpc, devnet } from "@solana/kit";

const LAMPORTS_PER_SOL = 1_000_000_000;

const rpc = createSolanaRpc(devnet("https://api.devnet.solana.com"));

const wallet = "YOUR_PUBLIC_KEY";

const signatures = await rpc
  .getSignaturesForAddress(wallet, { limit: 1 })
  .send();

const signature = signatures[0].signature;

const tx = await rpc
  .getTransaction(signature, {
    encoding: "jsonParsed",
    maxSupportedTransactionVersion: 0,
  })
  .send();

for (const ix of tx.transaction.message.instructions) {
  if (ix.program === "system" && ix.parsed?.type === "transfer") {
    const sender = ix.parsed.info.source;
    const receiver = ix.parsed.info.destination;
    const amount =
      Number(ix.parsed.info.lamports) / LAMPORTS_PER_SOL;

    console.log({ sender, receiver, amount });
  }
}

👉 Insight:
Everything boils down to:

• Accounts (public keys)
• Signatures (proof of ownership)

🔐 Day 4: Wallets = UX Layer Over Identity

I explored:

• CLI wallet
• Browser wallet
• Mobile wallet

All use the same keypair—but differ in how they protect it.

🦊 Phantom Wallet Use Case (Real dApp Flow)

Here’s where it clicks.

Using a browser wallet like Phantom, you don’t create accounts—you connect your identity.

// Connect Phantom Wallet
const provider = window.solana;

if (provider?.isPhantom) {
  const response = await provider.connect();
  console.log("Public Key:", response.publicKey.toString());
}

👉 This gives you the same public key as your identity.

✍️ Signing a Transaction (User Approval)

const transaction = new Transaction().add(
  SystemProgram.transfer({
    fromPubkey: provider.publicKey,
    toPubkey: RECEIVER,
    lamports: 1000000,
  })
);

const signedTx = await provider.signTransaction(transaction);

👉 Key difference from CLI:

• Phantom shows a popup
• User must approve before signing

💡 Why This Matters

In Web2:

• App controls your identity
• You log in

In Web3:

• You control your identity
• Apps request permission

🌐 Public Keys vs Usernames

Example Solana address:

14grJpemFaf88c8tiVb77W7TYg2W3ir6pfkKz3YjhhZ5

Unlike usernames:

• Not owned by a company
• Works across all apps
• Cannot be taken away

⚖️ Tradeoffs

Lose your private key → lose everything.

💻 My Repo

I’ve been documenting everything here:
👉 https://github.com/bitanb1999/100-days-of-solana

🔥 Final Take

Identity in Web3 isn’t something you sign up for.
It’s something you generate and carry everywhere.

• Public key → who you are
• Private key → what you control

Everything else builds on that.