Cryptography is a benediction to information processing and communications, because it allows people to store information securely and conduct private communications over long distances. There are mainly two aspects in cryptography, algorithms and the key used. The important encryption techniques are symmetric ,asymmetric, hash function algorithms.

Symmetric-key cryptography refers to encryption methods in which both the sender and receiver share the same key of decryption.

In asymmetric key cryptography,the encryption key is the public and decryption key is the private key or secret key individually.

Hash functions are extremely useful and appear in almost all information security applications.

A hash function is a mathematical function that converts a numerical input value into another compressed numerical value. The input to the hash function is of arbitrary length but output is always of fixed length.


Cryptovirology was born out of scientific curiosity of what the future may hold for software attacks that merge cryptographic technology with malware. It started at Columbia University as a natural by-product of an unnatural union. A former hacker placed in a room with a cryptographer, both given ample time with which to contemplate the dystopia of tomorrow

Cryptovirology is the study of the applications of cryptography for implementation of malicious software. It is about, how modern cryptographic paradigms and
tools can be used to strengthen, improve, and develop new malicious software attacks.
Cryptovirology attacks have been categorized to give enhanced privacy to the malware and be more robust against reverse-engineering, secondly give the attacker enhanced anonymity while
communicating with deployed malware.


Kleptography is the study of stealing information securely. Kleptography was introduced by Adam Young and Moti Yung in the Proceedings of Advances in Cryptology—Crypto ’96. A kleptographic attack is a forward-engineering attack that is built into a cryptosystem or cryptographic protocol.Kleptography is a subfield of Cryptovirology

Kleptography is the study of stealing the information more securely. A kleptographic attack is an attack in which a malware designer deploys an asymmetric backdoor. In this attack, there is an explicit distinction between the confidentiality of the messages, and awareness of the attack is taking place. A secure kleptographic attack is truly undetectable as long as the cryptosystem is a black-box. A kleptographic attack is an asymmetric backdoor attack that can only be used by the designer that carries out the attack. If reverse engineering detects the key generation code then he or she will get known that a kleptographic attack is underway