Can third party send an ERC20 token transaction to the Ethereum blockchain

Question

I want to create a smart contract in which people can transfer tokens without ether in their wallets.

Suppose A wants to transfer ERC20 tokens to B, but he does not have ether in his wallet.

Does third party C can send the transaction for A and therefore pay the gas? Is it possible to create a function in the contract for this usage?

I have searched online for a solution and could not find one.

Answer 1

There are 2 options with their pros and cons:

1. The usage of signatures

   • Every function in your smart contract must have a signature parameter.

   • People who want to interact with the smart contract must sign the function parameters with their account's private key and send it to the smart contract owner (via any communication channel).

   • The owner then submits the parameters along with the signature to the blockchain, paying for gas. The signature guarantees that the message was approved by the user.

2. Refund used gas at the end of the transaction. A modifier refundGasCost can be used for this. Hope this answers your question.