Most symmetric algorithms use either a block cipher or a stream cipher. They are both symmetric, so they both use the same key to encrypt or decrypt data. However, they divide data in different ways. A block cipher encrypts data in specific-sized blocks, such as 64-bit blocks or 128-bit blocks.

Is block cipher symmetric or asymmetric?

Stream and block ciphers are usually used with symmetric keys.

Is block cipher asymmetric?

Block modes for asymmetric encryption

Since asymmetric encryption limits the maximum size of the plaintext, you might think that we should use block modes with asymmetric encryption algorithms to encrypt arbitrary-length messages. In fact, this can be done. You could use CBC or CTR.