The range of possible values of the key is called the keyspace . Both the encryption and decryption operations use this key. Some algorithms use a different encryption key and decryption key. That is, the encryption key is different from the corresponding decryption key. This means that the algorithm can be published and analyzed.
Products using the algorithm can be mass-producted.
A cryptosystem is an algorithm, plus all possible plaintexts, ciphertexts and keys. Symmetric algorithms , sometimes called conventional algorithms, are algorithms where the encryption key can be calculated from the decryption key and vice versa. In most symmetric algorithms, the encryption ket and the decryption key are the same. As long as the communication needs to remain secret, the key must remain secret. Symmetric algorithms can be divided into two categories.