Can isn't a verb, it's a modal. So it doesn't have a tense.
Modals modify existing verbs (which don't change tense when used with a modal) and cover situations that don't fit neatly in past or present categories.
Now, often you can substitute be able to for can, and often you can substitute was able to for could, but can and especially could have many more uses and meanings. Basically, could isn't strictly a "past form" of can.
Things get more complex if you were to throw have in there: You can say I could have done X, and I can't have done X, but you can't say I can have done X (don't confuse this with I can have X done). Because of this could is more associated to past tense things than can and typically sounds better.
Furthermore, in both your examples, can/could is probably (guessing without context) really meaning allowed to, not able to, and may would technically be more accurate. However since modals are often "misused" for politeness and other reasons, no one usually cares.
So use either one; could will sound better but it's not wrong to use can.