What should I set as the cost basis for my gift?
In Norway, if you receive a gift from a Norwegian taxpayer you inherit their cost basis. If the person who gave you the gift does not recall the cost of the crypto gift a possible solution is to set the cost basis to zero. This way you definitely will not pay too little taxes once you sell the crypto you received.
If the gift comes does not come from a Norwegian taxpayer you can set the cost basis as the marketvalue at the time you receive the gift.