*2.1.4 Cryptography*

Cryptography is a technique that converts plain text to cipher text using various encryption algorithms to encode messages in a way that cannot be read. It is a method of storing and transmitting data in specific form using cryptography techniques so that only intended persons can read and process it.

In data mining applications, cryptography-based techniques are used to protect privacy during data collection and data storage [25, 28], and guarantee a very high level of data privacy [23]. Encryption is generally costly due to time and computational complexity. Hence, as the volume of data increases, the time to process on encrypted data increases and creates a potential barrier to real-time analysis [29].

Secure multiparty computing (SMC) is a special encryption protocol where, when there is more than one participating party, the interested parties learn nothing but results [30, 31]. The SMC calculation must be done carefully so that it does not reveal sensitive data, but the calculated result can enable the parties to estimate the value of sensitive data.
