Define Block Cipher

Question

Define Block Cipher? Briefly explain it.

Answer 1

A block cipher converts a fixed-length block of plaintext data into a block of cipher-text data of similar length. This transformation occurs beneath the action of a user-provided secret key. Decryption is executed by applying the reverse transformation to the cipher-text block employing similar secret key. The fixed length is termed as the block size, and for many block ciphers, the block size is of 64 bits.