Cryptography refers to a technique for storing and sending data in a specific form which can be read or processed only by those who are meant to read it. This is why cryptography will include codes that have been written for keeping specific data secure and private. It will convert the information into a form which cannot be read unless you are an authorized user. So, no person can decode this data into a readable format and thereby compromise it.
Modern cryptography has some key objectives to fulfill, such as, confidentiality so that data can only be read by those, for whom it is meant, integrity so that the data cannot be changed whether in transit or at rest. It also ensures non-repudiation so that the data creator cannot deny his intentions later and authentication so that both the sender and the receiver may confirm one another’s identity.
This is why information security will make use of the cryptography method at different levels. You will need a key for decrypting information in such a case. You will find multiple algorithms for cryptography, some of which are SKC or Secret Key Cryptography, PKC or Public Key Cryptography and Hash Functions.