Github: https://github.com/a3994288/signature...

Credit:   / off-chain-whitelist-with-on-chain-verifica...  

Other examples: https://docs.soliditylang.org/en/v0.8...

What is Cryptographic:   / the-magic-of-digital-signatures-on-ethereum  

Sign message with ethersjs: https://docs.ethers.io/v5/getting-sta...

ECDSA: https://github.com/OpenZeppelin/openz...

Verify your signature: https://etherscan.io/verifySig