How to distinguish between a block cipher and a random permutation by lowering the input entropy

IEEE 35th International Carnahan Conference on Security Technology. Londres, 16-19 October 2001A novel cryptanalysis technique is presented, and its suitability for distinguishing a block cipher algorithm or a hash function from a random permutation is explained. Additionally, we propose a genetic algorithm based implementation and show some preliminary results of these ideas on reduced rounds versions of the block cipher TEA

On Resistance of DES to Related-Key Differential Cryptanalysis

The key schedule of the Data Encryption Standard is analyzed, and it is shown that the properties of the permuted choice PC-2 transformation and the number of bits that are left shifted during the key generation are critical for the security of the algorithm. More precisely, we were able to mount a low complexity related-key attack on DES with slightly modified key schedule although no related-key attack is known for the original algorithm

Inisialisasi Key Generating Kriptografi AES Pada Pendekatan Protokol SMSSEC

Perkembangan teknologi di dunia internet tidak terlepas dari saling keterkaitannya dengan kriptografi yang menyediakan layanan dalam pengamanan data. Salah satu pengamanan data yang diperlukan yakni penyandian data dengan proses komputasi kriptografi yang digunakan saat berlangsungnya proses melibatkan data penting seperti yang ada pada perbankan, yakni pertukaran data rahasia yang dilakukan oleh seseorang untuk memudahkan atau memfasilitasi kegiatannya. Kebutuhan untuk kemudahan dalam akses ke data pribadinya di dunia perbankan seperti transaksi cek saldo atau transfer antar rekening sangatlah krusial dan perlu dijaga kerahasiaannya. Metode kriptografi klasik sudah tidak lagi mumpuni jika diterapkan untuk dijadikan salah satu solusi dalam pengamanan data transaksi tersebut. Oleh karena itu dalam penelitian ini, diusulkan suatu rancangan baru mengenai metode pengamanan data yang dapat digunakan pada aplikasi perbankan dengan biaya komputasi yang minimum. Adapun rancangan baru tersebut melibatkan pendekatan protokol SMSSecure yang di dalamnya menyertakan sekaligus tiga tipe algoritma kriptografi. Pada penelitian ini juga dilakukan pembaharuan proses kriptografi simetrik Advanced Encryption Standard (AES) yakni pada inisialisasi pembuatan kunci enkripsi/dekripsi. Dari hasil simulasi pengujian diperoleh hasil bahwa performansi waktu proses komputasi dari usulan rancangan mencapai empat sampai lima belas kali jauh lebih cepat dibanding rancangan awal. Juga ada penghematan dari hasil analisis parameter konsumsi memory yang dibutuhkan selama satu kali transaksi yakni sekira tiga kilo bytes. Namun, parameter avalanche effect yang dihasilkan jauh dari kriteria baik dan berada di nilai AE sebesar 78,74%.Perkembangan teknologi di dunia internet tidak terlepas dari saling keterkaitannya dengan kriptografi yang menyediakan layanan dalam pengamanan data. Salah satu pengamanan data yang diperlukan yakni penyandian data dengan proses komputasi kriptografi yang digunakan saat berlangsungnya proses melibatkan data penting seperti yang ada pada perbankan, yakni pertukaran data rahasia yang dilakukan oleh seseorang untuk memudahkan atau memfasilitasi kegiatannya. Kebutuhan untuk kemudahan dalam akses ke data pribadinya di dunia perbankan seperti transaksi cek saldo atau transfer antar rekening sangatlah krusial dan perlu dijaga kerahasiaannya. Metode kriptografi klasik sudah tidak lagi mumpuni jika diterapkan untuk dijadikan salah satu solusi dalam pengamanan data transaksi tersebut. Oleh karena itu dalam penelitian ini, diusulkan suatu rancangan baru mengenai metode pengamanan data yang dapat digunakan pada aplikasi perbankan dengan biaya komputasi yang minimum. Adapun rancangan baru tersebut melibatkan pendekatan protokol SMSSecure yang di dalamnya menyertakan sekaligus tiga tipe algoritma kriptografi. Pada penelitian ini juga dilakukan pembaharuan proses kriptografi simetrik Advanced Encryption Standard (AES) yakni pada inisialisasi pembuatan kunci enkripsi/dekripsi. Dari hasil simulasi pengujian diperoleh hasil bahwa performansi waktu proses komputasi dari usulan rancangan mencapai empat sampai lima belas kali jauh lebih cepat dibanding rancangan awal. Juga ada penghematan dari hasil analisis parameter konsumsi memory yang dibutuhkan selama satu kali transaksi yakni sekira tiga kilo bytes. Namun, parameter avalanche effect yang dihasilkan jauh dari kriteria baik dan berada di nilai AE sebesar 78,74%

Comparison of Hardware and Software Based Encryption for Secure Communication in Wireless Sensor Networks

International audienceThis paper deals with the energy efficient issue of cryptographic mechanisms used for secure communication between devices in wireless sensor networks. Since these devices are mainly targeted for low power consumption appliances, there is an effort for optimization of any aspects needed for regular sensor operation. On a basis of utilization of hardware cryptographic accelerators integrated in microcontrollers, this article provides the comparison between software and hardware solutions. Proposed work examines the problems and solutions for implementation of security algorithms for WSN devices. Because the speed of hardware accelerator should be much higher than the software implementation, there are examination tests of energy consumption and validation of performance of this feature. Main contribution of the article is real testbed evaluation of the time latency and energy requirements needed for securing the communication. In addition, global evaluation for all important network communication parameters like throughput, delay and delivery ratio are also provided

Improved Related-Key Attacks on DESX and DESX+

In this paper, we present improved related-key attacks on the original DESX, and DESX+, a variant of the DESX with its pre- and post-whitening XOR operations replaced with addition modulo $2^{64}$. Compared to previous results, our attack on DESX has reduced text complexity, while our best attack on DESX+ eliminates the memory requirements at the same processing complexity

Second Preimages for Iterated Hash Functions Based on a b-Block Bypass

In this article, we present a second preimage attack on a double block-length hash proposal presented at FSE 2006. If the hash function is instantiated with DESX as underlying block cipher, we are able to construct second preimages deterministically. Nevertheless, this second preimage attack does not render the hash scheme insecure. For the hash scheme, we only show that it should not be instantiated with DESX but AES should rather be used. However, we use the instantiation of this hash scheme with DESX to introduce a new property of iterated hash functions, namely a so-called b-block bypass. We will show that if an iterated hash function possesses a b-block bypass, then this implies that second preimages can be constructed. Additionally, the attacker has more degrees of freedom for constructing the second preimage

A Key Scheduling Algorithm Based on Dynamic Quasigroup String Transformation and All-Or-Nothing Key Derivation Function

Cryptographic ciphers depend on how quickly the key affects the output of the ciphers (ciphertext). Keys are traditionally generated from small size input (Seed) to a bigger size random key. Key scheduling algorithm (KSA) is the mechanism that generates and schedules all sub-keys for each round of encryption. Researches have suggested that sub-keys should be generated separately to avoid related-key attack. Similarly, the key space should be disproportionately large to resist any attack meant for secret keys. To archive that, some algorithms adopt the use of matrixes such as quasigroup, Hybrid cubes and substitution box (S-box) to generate the encryption keys. Quasigroup has other algebraic property called “Isotopism”, which literally means Different quasigroups that has the same order of elements but different arrangements. This paper proposed a Dynamic Key Scheduling Algorithm (KSA) using Isotope of a quasigroup as the dynamic substitution table. The proposed algorithm is a modification and upgrade to Allor-nothing Key Derivation Function (AKDF). To minimize the complexity of the algorithm, a method of generating Isotope from a non-associative quasigroup using one permutation is achieved. To validate the findings, non-associativity of the generated isotopes has been tested and the generated isotopes appeared to be non-associative. Furthermore, the proposed KSA algorithm will be validated using the Randomness test proposed and recommended by NIST, Avalanche and Correlation Assessment test