Cryptography is the art and science of designing security algorithms to provide certain security services. Cryptanalysis is the art and science of analyzing and defeating the security claims of these algorithms. The branch of science that embodies both cryptography and cryptanalysis is called Cryptology. The main goal of cryptography is to secure communications between two parties (sender and receiver) by transforming a message (plaintext) into a scrambled message (ciphertext) using a secret key. The process of transforming plaintext into ciphertext is called encryption and the process of unscrambling the ciphertext to recover the original plaintext is called decryption. Modern cryptography provides the following: authentication, data integrity, and non-repudiation, to solve various aspects of information security problems.

Symmetric-key ciphers use one key for encryption and decryption between two parties. Thus, they require that the two communicated parties agreed beforehand on a key. The whole security of symmetric-key primitives depends on the secrecy of the key; revealing the key means that encryption and decryption are possible by anyone. Symmetric-key ciphers are used to provide the services of confidentiality and authentication and they can be divided into two schemes: block ciphers and stream ciphers. In our group, we study the cryptanalysis of symmetric ciphers in bot classical as well as the quantum framework.