object {
     string      rw babel-mac-key-name;
     boolean     rw babel-mac-key-use-send;
     boolean     rw babel-mac-key-use-verify;
     binary      -- babel-mac-key-value;
     string      rw babel-mac-key-algorithm;
    [operation      babel-mac-key-test;]
} babel-mac-key-obj;