Encrypts the wallet with passphrase. After this, any calls that interact with private keys will require the passphrase.
passphrasestringREQUIREDcurl --user myuser --data-binary '{"jsonrpc":"1.0","id":"1","method":"encryptwallet","params":["my passphrase"]}' -H 'content-type:text/plain;' http://127.0.0.1:8332/"wallet encrypted; The keypool has been flushed and a new HD seed was generated. You need to make a new backup."