Korkmaz, Sinan Emir
At the dawn of quantum computing, our most trusted cryptosystems are at significant risk. All vastly used and standardized public-key algorithms such as RSA and ECC were designed to withstand the attacks from classical computers by using integer factorization and discrete logarithm problems. However, quantum computers can generate the whole solution space for these problems that contains all the possible keys and reduce it to the correct key in polynomial time. Therefore, we need to start using a new public key encryption algorithm before the first full-scale quantum computer starts to work. To select this new algorithm, NIST organized a competition in 2016. They received 59 submissions in the field of encryption. With the passing rounds, algorithms are heavily investigated according to security and performance metrics by researchers all around the globe. In this thesis work, we focused on the NTRU, one of the third-round candidate algorithms. This lattice-based algorithm uses Shortest Vector Problem as the encryption function and has the ability to provide secrecy against quantum computers. We worked on the hardware implementation of the NTRU. By implementing an algorithm on FPGA, we can benefit from gate-level parallelism and design algorithm-specific logical blocks. We implemented encryption, decryption, and data processing modules with our proposed improvements. The key generation module is not implemented be- cause generated keys can be loaded manually and have a long life of usage. Our design focuses on resource optimization and flexibility. These properties enabled us to provide a suitable solution for low-power embedded network devices.


Quantum safe digital signatures from symmetric key primitives
Erbaş, Şeyma; Cenk, Murat; Department of Cryptography (2019)
When powerful quantum computers are built, they will break most of the public key cryptography schemes due to Shor’s quantum algorithm. Therefore, public key cryptography algorithm schemes that is secure against classical and quantum computers are needed. In this thesis, we study Picnic algorithm, a post-quantum digital signature scheme. Picnic digital signature algorithm has the security of symmetric-key primitives that is considered to be secure against quantum attacks. In Picnic algorithm, zero knowledge...
Keskinkurt Paksoy, İrem; Cenk, Murat; Department of Cryptography (2022-7-28)
One of the quantum-safe cryptography research areas is lattice-based cryptography. Most lattice-based schemes need efficient algorithms for multiplication in polynomial quotient rings. The fastest algorithm known for multiplication is the Number Theoretic Transform (NTT), which requires certain restrictions on the parameters of the ring, such as prime modulus. Direct NTT application is not an option for some schemes that do not comply with these restrictions, e.g., the two finalists of the PQC standardizati...
On statistical analysis of synchronous stream ciphers
Sönmez Turan, Meltem; Doğanaksoy, Ali; Department of Cryptography (2008)
Synchronous stream ciphers constitute an important class of symmetric ciphers. After the call of the eSTREAM project in 2004, 34 stream ciphers with different design approaches were proposed. In this thesis, we aim to provide a general framework to analyze stream ciphers statistically. Firstly, we consider stream ciphers as pseudo random number generators and study the quality of their output. We propose three randomness tests based on one dimensional random walks. Moreover, we theoretically and experimenta...
Impossible differential cryptanalysis of reduced round HIGHT
Tezcan, Cihangir; Doğanaksoy, Ali; Department of Cryptography (2009)
Design and analysis of lightweight block ciphers have become more popular due to the fact that the future use of block ciphers in ubiquitous devices is generally assumed to be extensive. In this respect, several lightweight block ciphers are designed, of which HIGHT is proposed by Hong et al. at CHES 2006 as a constrained hardware oriented block cipher. HIGHT is shown to be highly convenient for extremely constrained devices such as RFID tags and sensor networks and it became a standard encryption algorithm...
Quantum-resistant multivariate quadratic systems and digital signatures
Altundağ, Esen; Cenk, Murat; Department of Cryptography (2019)
In the light of technological advances, scientists expect that quantum computers will be generated and substitute with classical ones, then all symmetric and asymmetric (public-key) cryptosystems will be invalid in the near future. This causes the need for quantum-resistant algorithms all araund the world. That’s why, we have focused on multivariate public-key cryptosystems as a kind of post-quantum cryptography. In order to explain the root idea behind this kind of cryptosystems, as a starting point, the M...
Citation Formats
S. E. Korkmaz, “COMPACT AND FLEXIBLE NTRU IMPLEMENTATION ON FPGA,” M.S. - Master of Science, Middle East Technical University, 2022.