curl --request POST \
--url https://api.privy.io/v1/wallets/{wallet_id}/rpc \
--header 'Authorization: Basic <encoded-value>' \
--header 'Content-Type: application/json' \
--header 'privy-app-id: <privy-app-id>' \
--data '{
"method": "signMessage",
"params": {
"message": "aGVsbG8sIFByaXZ5IQ=",
"encoding": "base64"
}
}
'