Which of the statements below are correct

A probabilistic encryption scheme uses randomness to achieve a non$-$deterministic generation of a cyphertext.

The public$-$key cryptography has been introduced to be used for encryption, but if the asymmetric relation in terms of the complexity in computing keys is reversed, it can be used for authentication rather than for encryption.

Security of block ciphers does not depend on combining multiple times of the confusion and diffusion operations, as these operations do not increase when combined in multiple numbers.

In modular arithmetic mod $2$ addition and subtraction are different operations.