[Narrator] The answer is 300, which you'll need to do to share the key among 4 people.
Alice will need to compute 3 keys of 100 bits long,
and one way to do this is to give 1 person the secret XOR'd with all of the keys,
and to give each person one of the keys.
There's no way to do this with perfect secrecy using fewer than 300 key bits
because that would mean either we're not fully sharing the secret.
That some party has no part of some part of the secret
or that we're reusing key bits.
