Cryptanalysis of symmetric key schemes using classical and quantum techniques/ Mostafizar Rahman

Thesis (Ph.D.) - Indian Statistical Institute, 2022

Includes bibliographical references

Introduction -- Background -- Differential Attacks on FlexAEAD -- Yoyo attacks on internal keyed permutation of FlexAEAD -- Yoyo Attacks on AES-based Designs -- Boomeyong Attacks on AES-based Designs -- Quantum Attacks on Symmetric Designs beyond Grover’s Search -- Quantum Resource Estimation -- Conclusion

Guided by Prof. Goutam Paul

Symmetric key cryptography refers to the encryption methods in which the same key
is used by both the sender and the receiver. Cryptanalysis is a process of finding
vulnerabilities in cryptographic algorithms in order to distinguish the algorithm, or
to retrieve the plaintext from ciphertext without the knowledge of the secret key, or
sometimes to recover the secret key also. In this work, in addition to using existing cryptanalysis techniques to analyze some recent ciphers, we also develop novel
cryptanalysis techniques.
The cryptanalysis techniques that are involved here are based on both classical
and quantum computing models. In classical cryptanalysis, first of all, we break the
authenticated encryption scheme FlexAEAD by mounting forgery using the devised
iterated truncated differentials. Further, we mount key recover attacks on the underlying keyed permutation of FlexAEAD. We develop new techniques of cryptanalysis
by augmenting yoyo game with classical, impossible and improbable differentials and
its impact is shown by applying it on public permutation AESQ and AES in the
known-key setting. Another new technique is developed by embedding a boomerang
attack within a yoyo game, which is shown to be effective by breaking the claimed
security of AES-like block ciphers. In quantum cryptanalysis, we analyze several
symmetric key schemes by using Simon’s algorithm or by combining Simon’s with Grover’s algorithms. We also provide cost estimation for mounting Grover’s attack on lightweight block ciphers KATAN and Present. To strengthen the validity of our results, all practical attacks are experimentally verified.