EIP-2612: Permit

EIP-2612 introduce le approvazioni via firma

Caratteristiche principali

Gasless, single-call approvals: A holder signs an off-chain EIP-712 message and one permit() call instantly sets the allowance while verifying the signature, removing the need for a separate on-chain approve and streamlining UX.
Security & backward compatibility: Each permit consumes a unique, ever-increasing nonce and the signature is bound to the token's EIP-712 domain (name, chain ID, contract address). The extension adds < 200 bytes to a standard ERC-20, leaving balances and transfers untouched.
Seamless DeFi & wallet integration: DEXs, lending protocols, routers, and meta-TX relayers can batch permit -> action in one atomic transaction, while wallets like MetaMask and Ledger present it as a familiar Sign Message flow instead of a gas-priced approval.

Perché non è necessario su Solana

Il modello di account di Solana elimina questa necessità

Modello di approvazione token

Come funzionano le approvazioni su Solana

Modello fee payer

Chi paga le commissioni di transazione

Come implementare

Guida all'implementazione

Esempio 1

Implementazione base

javascript

import { Connection, Keypair, PublicKey, Transaction } from "@solana/web3.js";
import {
  createApproveInstruction,
  createTransferInstruction,
  getAssociatedTokenAddressSync
} from "@solana/spl-token";

const connection = new Connection("https://api.devnet.solana.com");
const owner = Keypair.generate();
const delegate = owner.publicKey;
const recipient = new PublicKey("DESTINATION_WALLET");
const mint = new PublicKey("TOKEN_MINT");
const amount = 1_000_000;

const ownerATA = getAssociatedTokenAddressSync(mint, owner.publicKey);
const recipientATA = getAssociatedTokenAddressSync(mint, recipient);

const ixApprove = createApproveInstruction(ownerATA, delegate, owner.publicKey, amount);
const ixTransfer = createTransferInstruction(ownerATA, recipientATA, owner.publicKey, amount);

const tx = new Transaction().add(ixApprove, ixTransfer);
tx.feePayer = owner.publicKey;
tx.recentBlockhash = (await connection.getLatestBlockhash()).blockhash;

tx.sign(owner);
const sig = await connection.sendRawTransaction(tx.serialize());
console.log("Sent (self-sponsored):", sig);

Esempio 2

Implementazione avanzata

javascript

import { Connection, Keypair, PublicKey, Transaction } from "@solana/web3.js";
import { createTransferInstruction, getAssociatedTokenAddressSync } from "@solana/spl-token";

const connection = new Connection("https://api.devnet.solana.com");
const owner     = Keypair.generate();          // replace with real keypair
const feePayer  = Keypair.generate();          // replace with real keypair
const recipient = new PublicKey("DESTINATION_WALLET");
const mint      = new PublicKey("TOKEN_MINT");
const amount    = 500_000;

const ownerATA     = getAssociatedTokenAddressSync(mint, owner.publicKey);
const recipientATA = getAssociatedTokenAddressSync(mint, recipient);

const ix = createTransferInstruction(ownerATA, recipientATA, owner.publicKey, amount);

const tx = new Transaction().add(ix);
tx.feePayer        = feePayer.publicKey;
tx.recentBlockhash = (await connection.getLatestBlockhash()).blockhash;

tx.partialSign(owner);
tx.sign(feePayer);

const sig = await connection.sendRawTransaction(tx.serialize());
console.log("Sent (relayer-sponsored):", sig);

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