sudo hdparm --user-master m --security-unlock '                                ' /dev/sda
security_password: "                                "

/dev/sda:
 Issuing SECURITY_UNLOCK command, password="                                ", user=master
SG_IO: bad/missing sense data, sb[]:  70 00 05 00 00 00 00 0a 04 51 40 01 21 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00