Users either don't realize or don't care about the security problems inherent in their system. Modern cryptography solves this problem with a key . This might be any one of a large number of values. 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.