What type of primary key we need to use for specific length of bits in Cassandra?

Question

I want to know in which situations which type of primary key I need to use.
Situations:
1. If I need 64 bit key than is bigint is the best for it? If I will chose text type will performance will be the same if I will put keys which is not more then 64 bits?
2. If I need a primary key which is more then 64 bits and less then 128 bits (let say 80 bits) then which data type I have to use for primary key?

Answer 1

For variable bits length you could use a blob field type. Or maybe throw away the small optimization you are looking for and stick with two bigint type primary key and move ahead with your project...