Nonce Reuse Count

Problem

Given a list of nonces, return how many distinct nonce values were used more than once. Even a single reuse breaks stream cipher confidentiality.

Hint

The count is over distinct values, not over extra occurrences.

case 1

in: [[1,2,3]]

expected: 0

case 2

in: [[1,1,2]]

expected: 1

case 3

in: [[1,1,2,2,3]]

expected: 2

case 4

in: [[5,5,5,5]]

expected: 1

Starter codePython

def nonce_reuse_count(nonces):
    # Your code here
    pass

4 test cases · run your code against them in the editor