DES_set_odd_parity() sets the parity of the passed key to odd.

奇偶校验设置为奇

 DES_set_key_checked() will check that the key passed is of odd parity and is not a week or semi-weak key. If the parity is wrong, then -1 is returned. If the key is a weak key, then -2 is returned. If an error is returned, the key schedule is not generated.