A riddle

Looking in the horse stall Kushina dug her hands threw the hay till she found a piece of folded paper. taking a closer look she pulled the paper up and read it:

I am used for one code but not the other. my loyalty knows no equal as I follow my master onto freedom. what am i?

"Of course he could not just tell me what animal could he. luckily its pretty simple to figure out," Kushina said to herself. the answer was clearly a dog. since a dog is considered incredibly loyal to its master. now she needs to figure out if the number was for the door or box. taking another look Kushina guesses that it must be the door since it is her key to freedom from this game. with a smile Kushina put the paper on a small table in the middle of the room and looked at some of the other stalls as well as some of the equipment in the room. she was sure there were more clues hidden.