For block 12344:
20:58:10
signmessage APLLrWbHapoRVxLAxBUkDU1hkx4VbCJHQX "Koooooj owns this address"
20:58:10
IBBD3qd/bbh5npcj7pEQCBqZUwiYaaE/y097+P0EBeB5fH4eJCqvNzrxzm20P6kWFq/0wmp0cZQTHk78cpfaYbM=
For block 17302:
21:00:27
signmessage AbrPM2J3WLvgz87t13wU46VwvVW5dM1Vdq "Koooooj owns this address"
21:00:27
IH8dQ+I2e4WWZIpXbqhXrquLXMnNdx847+HUeuadcqyeB77XPe3tmN2bG/FdOPZv7id9Q0eMuQ4UO7iBaq0wUf0=
I think I got the right blocks and signed correctly; my local QT client returns true upon verification requests.