Which of the following statements about cryptographic systems is$/$are true?

Group of answer choices

If the sender and receiver each use a different key, the system is referred to as public$-$key encryption.

A stream cipher processes the input one block of elements at a time, producing an output block for each input block.

All encryption algorithms are based on two general principles: substitution, in which elements in the plaintext are rearranged; and transposition, in which each element in the plaintext is mapped into another element.

A block cipher processes the input elements continuously.