Withdraw Operation

This operation converts encrypted Tongo balance to ERC20 tokens and sends them to the given starknet account address. The parameters are:

• amount: The amount of Tongo balance to withdraw.
• to: The starknet account address to send the ERC20 to.
• sender: The sender of the transaction.

Convert encrypted Tongo balance back to ERC20 tokens.

const withdrawOp = await senderAccount.withdraw({
    to: "RECEIVER_STARKNET_ACCOUNT_ADDRESS",
    amount: "AMOUNT_TO_WITHDRAW"
    sender: "SENDER_ADDRESS"
});

const tx = await signer.execute([withdrawOp.toCalldata()]);
await provider.waitForTransaction(tx.transaction_hash);

Balance Handling

When receiving a Withdraw operation for some amount, the cairo contract creates an ElGamal encryption of that amount for the account public key and fixed randomness. This encryption is subtracted from balance of the account. The pending balance of the account is not manipulated in this operation.

Zero-Knowledge Proof

In this operation, the ZK proof given by the sender shows:

• Ownership of the user account.
• After the subtraction, the user's balance is positive.