Reveals the private key corresponding to 'address'. Only for legacy wallets.
addressstringREQUIREDcurl --user myuser --data-binary '{"jsonrpc":"1.0","id":"1","method":"dumpprivkey","params":["address"]}' -H 'content-type:text/plain;' http://127.0.0.1:8332/"5HueCGU8rMjxEXxiPuD5BDku4MkFqeZyd4dZ1jvhTVqvbTLvyTJ"