Statistical Analysis of Reduced Round Compression Functions of SHA-3 Second Round Candidates

National Institute of Standards and Technology announced a competition in 2008, of which the winner will be acknowledged as the new hash standard SHA-3. There are 14 second round candidates which are selected among 51 first round algorithms. In this paper, we apply statistical analysis to the second round candidate algorithms by using two different methods, and observe how conservative the algorithms are in terms of randomness. The first method evaluates 256-bit outputs, obtained from reduced round versions of the algorithms, through statistical randomness tests. On the other hand, the second method evaluates the randomness of the reduced round compression functions based on certain cryptographic properties. This analysis gives a rough idea on the security factor of the compression functions

Cryptographic Randomness Testing of Block Ciphers and Hash Functions

One of the most basic properties expected from block ciphers and hash functions is passing statistical randomness testing, as they are expected to behave like random mappings. Previously, testing of AES candidate block ciphers was done by concatenating the outputs of the algorithms obtained from various input types. In this work, a more convenient method, namely the cryptographic randomness testing is introduced. A package of statistical tests are designed based on certain cryptographic properties of block ciphers and hash functions to evaluate their randomness. The package is applied to the AES finalists, and produced more precise results than those obtained in similar applications

Practical Improvements to Statistical Ineffective Fault Attacks

Statistical Fault Attacks (SFA), introduced by Fuhr et al., exploit the statistical bias resulting from injected faults. Unlike prior fault analysis attacks, which require both faulty and correct ciphertexts under the same key, SFA leverages only faulty ciphertexts. In CHES 2018, more powerful attacks called Statistical Ineffective Fault Attacks (SIFA) have been proposed. In contrast to the previous fault attacks that utilize faulty ciphertexts, SIFA exploits the distribution of the intermediate values leading to fault-free ciphertexts. As a result, the SIFA attacks were shown to be effective even in the presence of widely used fault injection countermeasures based on detection and infection. In this work, we build upon the core idea of SIFA, and provide two main practical improvements over the previously proposed analysis methods. Firstly, we show how to perform SIFA from the input side, which in contrast to the original SIFA, requires injecting faults in the earlier rounds of an encryption or decryption operation. If we consider the start of the operation as the trigger for fault injection, the cumulative jitter in the first few rounds of a cipher is much lower than the last rounds. Hence, performing the attack in the first or second round requires a narrower parameter range for fault injection and hence less fault injection attempts to recover the secret key. Secondly, in comparison to the straightforward SIFA approach of guessing 32-bits at a time, we propose a chosen input approach that reduces the guessing effort to 16-bits at a time. This decreases the key search space for full key recovery of an AES-128 implementation from $2^{34}$ to $2^{19}$

Türkiye’ de kamu bankaları ve bankacılık sektöründeki yeri

ÖZETKamu işletmeciliği hemen bütün ülkelerde aynı gerekçelerle başlamıştır. Türkiye'nin gerekçelerinin daha da güçlü olduğu, Cumhuriyetin ilk dönemlerinde devlet eliyle sanayileşmeye karar verilmesinde, bazı zorunluluklar ve koşulların etkisi bulunduğu kanısı hayli yaygındır. Şöyle ki; Cumhuriyetin kurulmasından sonra ekonomik gelişmeyi hızlandırabilmek için devlet tarafından bir çok alanda işletmeler kurulmuştur. Özel sektörün sahip olduğu kaynakların yeni kurulan Cumhuriyetin sosyal ve ekonomik hedeflerini gerçekleştirmede yetersiz olması yatırımların büyük bir çoğunluğunun devlet tarafından yapılmasını zorunlu kılmıştır. Buna paralel olarak çeşitli sektörlerde finansman ihtiyacının karşılanabilmesi için uzman bankalar kurulmuştur. Etibank, Sümerbank, İller Bankası ve Halk Bankası farklı sektörleri ve hizmetleri finansal yönden desteklemek için bu dönemde kurulmuştur. Kamu kuruluşlarının ve bankalarının kurulmasında diğer bir neden ise milli sanayiyi, bankaları ve beraberinde ulusal sermaye birikimini oluşturmaktır. Diğer yandan, oluşturulan kamu kuruluşları ve bankalar ile piyasalar kontrol edilerek ve yönlendirilerek ekonomik ve sosyal kalkınma gerçekleştirilmeye çalışılmıştır.Kurumsal olarak kamu bankaları ve bankaların kurulmasındaki temel amaç uzun vadede ekonomide artı değer yaratmak ve bunları tekrar yatırımlara dönüştürerek toplumun kalkınmasını gerçekleştirmek olarak belirlenmiştir. Ayrıca şunu da ifade etmek gerekir ki, devlet işletmeciliğinin Cumhuriyetin ilk yıllarında başarılı örnekler verdiği yadsınamaz bir gerçektir.Ancak 1970'li yıllardan itibaren kamu kuruluşları ekonomik dengelerin oluşturulmasında her geçen gün toplum için ekonomik ve sosyal açıdan yük getirmiştir. Söz konusu yıllarda devletin artan fonksiyonları ve genişleyen boyutları ve bu durumun ortaya çıkardığı sorunlara Keynesyen iktisat politikasının çözüm önerememesi üzerine, temelde Klasik İktisat Teorisi ilkelerine dayalı, ancak onu bazı yönlerden eleştiren ve yeniden yorumlayan başka iktisat politikası yaklaşımları gündeme gelmiştir.Burada şunu da ifade etmek gerekir ki, Türkiye'de özelleştirme tartışmalarının yoğunlaştığı alanlardan birisi de kamu sermayeli bankalardır. Özellikle bankacılık sektöründe rekabetin, verimliliğin ve etkin kaynak kullanımının sağlanması, bankacılık sektörü-siyaset ilişkisinin ortadan kaldırılması ve kamu bankalarına çağdaş/dinamik bir yapı kazandırılması gibi hedefler özelleştirme uygulamalarının kamu sermayeli bankalar üzerinde yoğunlaşmasına sebebiyet vermiştir.Gerçekten de, Türk bankacılık sektörü incelendiğinde toplam mevduatların büyük bir bölümünün (yaklaşık %40) kamusal sermayeli bankaların elinde olduğu görülmekte, bu durum ise bankacılık sektöründe yaratılan kaynakların büyük bir bölümünün kamu kesimince yönlendirildiği anlamına gelmektedir. Sektörde yaratılan fonların kamu kesimine akması ise kaynak dengesini bozduğu gibi sektördeki rekabeti olumsuz yönde etkilemektedir. Genelde özel görevler için kurulan, ancak daha sonra ticaret bankacılığına yönelen kamu bankalarının sermaye yapısı rekabetçi olmalarını engelleyen en önemli nedenlerin baışında gelmektedir. Çünkü, kamu bankalarının finansal açıdan ülke hazinesine bağlı olması, sık sık politik müdahalelerle karşılaşmaları etkinliklerini azaltarak, finansal yapılarını bozmakta, sürekli zarar eden kamu bankalarını sermaye sorunu ile karşı karşıya bırakmaktadır.Öte yandan, Türkiye'de kamu bankalarının politik bir güç ve baskı aracı olarak kullanıldığı, hükümetlerin kamu bankalarını birer istihdam alanı ve ucuz kredi aracı olarak gördükleri ileri sürülmekte ve bu durumun, Türk bankacılık sektörünün en önemli sorunu olduğu iddia edilmektedir. Ayrıca, Türkiye'de bankacılık sektörü toplam aktifleri içinde devletin sahip olduğu/yönettiği bankaların aktiflerinin önemli bir yer tuttuğu ve bu bankaların bankacılık ilke ve kuralları yerine, politik öncelikler çerçevesinde yönetildiği, bu durum ise bankacılıkta rekabeti ve bankacılık sektörünün yapısını olumsuz yönde etkilediği ve kamu bankalarının kullandırdığı kredileri politik önceliklere göre tahsis etmekte olduğu da önemli iddialar arasındadır.Bu çalışmada, Türkiye'de ki kamu sermayeli ticaret bankalarının etkinlik ve verimlilik tartışmalarına ışık tutabilmek amacıyla kamu ve özel sermayeli bankalar çeşitli etkinlik/verimlilik ve diğer performans ölçüm oranları ile karşılaştırılmaktadır. Şöyle ki; önce, aktif büyüklüğü ölçütü esas alınarak Ziraat Bankası, Emlak Bankası, Halk Bankası ve Vakıflar Bankası olmak üzere 4 kamu sermayeli ticari banka ile Yapı ve Kredi Bankası, Akbank, İş Bankası ve Garanti Bankası olmak üzere 4 de özel sermayeli ticari banka seçilmiştir. Daha sonra ise söz konusu bankaların 1994-2000 dönemini kapsayan ve Türkiye Bankalar Birliği'nce yayınlanan gelir tablosu ve bilançoları kullanılarak, etkinlik, verimlilik ve diğer performans ölçüm oranları hesaplanmakta, böylece her iki banka grubu karşılaştırmalı bir şekilde ortaya konulmaktadır. Böylece, kamu bankalarının verimsiz olduğu yönündeki yaygın kanaat 1994-2000 dönemi verileri kullanılarak test edilmektedir.Üç bölümden oluşan bu çalışmanın birinci bölümünde ticari bankacılığa ilişkin teorik yaklaşımlar üzerinde durulmaktadır.İkinci bölümde ise; Türkiye'de ticari banka sayısı ile bu bankaların şube ve personel sayılarının yıllara göre gösterdiği gelişmeler kamu ve özel sermayeli banka grupları açısından irdelenmiştir. Daha sonra Türk Ticari Bankacılık sektöründe toplam aktifler, toplam mevduatlar ve toplam kredilerin yıllara göre kamu ve özel sermayeli banka grupları arasındaki dağılımı üzerinde, toplam aktif büyüklüğü ölçütü kullanılarak 4 kamu (Ziraat Bankası, Emlak Bankası, Halk Bankası ve Vakıflar Bankası) ve 4 de özel (Yapı ve Kredi Bankası, Akbank, İş Bankası ve Garanti Bankası) sermayeli banka olmak üzere toplam 8 banka seçilmiştir. Bu aşamadan sonra ise söz konusu bankaların Türkiye Bankalar Birliği'nce yayınlanan 1994-2000 dönemi bilançoları kullanılarak etkinlik, verimlilik ve diğer bankacılık performans ölçüm oranları her iki banka grubu için ayrı ayrı hesaplanmış ve bu oranlar vasıtasıyla kamu ve özel sermayeli banka gruplarının karşılaştırılması üzerinde durulmuştur.Üçüncü ve son bölümde ise; bankacılık sektörünün yeniden yapılandırma programı çerçevesinde kamu bankalarının yeniden yapılandırılması hususunda sağlanan gelişmeler üzerinde durulmuştur.ABSTRACTPublic administration has started because of some reasons in all states. In general opinion, The Turkish Republic's reasons have been more serious. Industrialization by the help of the Government has been a necessity during the early periods of the new Turkish Republic. After the foundation of the new Republic, lots of public administrations have been founded by the Government to speed up economic development. Assets of the private sector has been insufficient to realize the new Republic's social and economic targets to materialization of large scale investments by the Government. So, special banks have been founded by the Government to finance different sectors. Etibank, Sümerbank, İller Bankası and Halk Bankası have been founded in this period to support financially that different sectors. The other reason for the foundation of public administrations and banks has been realization of capital accumulation and support national industry. Social and economic development has been speeded up by the public organizations and banks.The main target for the foundation of the state banks has been to create public value, to increase savings and to use that savings for investments. In that system, public administrations and banks has resulted successful investments during the early years of the new Republic.But after 1970's, public administrations has caused some problems for economic balances. The role of the Government in the economic life has expanded. The public administrations has emerged as organizations that aren't profitable and efficient.When the Turkish banking sector is examined, we see that;Nearly half of the total deposits (nearly 40 %) is held in state banks. It means that, nearly half of the total savings in the Turkish banking sector is managed by the state banks. Management of the funds in the banking sector causes some problems and negative effects about fund-balances and competition in banking sector and economy.Capital forms of the state banks that have been founded some special targets, than started to manage with commercial banking are the main reasons that cause an incompetitive forms in the banking sector. By the financial way, state banks are dependent on Treasury and so state banks are often exposed to political interventions. That some political interventions caused problems on state banks' financial constructions and profitabilities.State banks have been used as political power and as a employment boxes for their supporters and voters and as a source of cheap loans for their supporters by the Governments. State banks' total assets has a large percentage in the total assets of the Turkish banking sector and instead of working in rules and style for profit and efficiency, are managed with political precedences.In this work, state and private sector banks has been compareted with several effectiveness, productivity and performance ratios to explain commercial banks' effectiveness and productivity in Turkish banking sector.First of all, 4 state banks that are T.C. Ziraat Bankası A.Ş., T.C. Emlak Bankası A.Ş., T.C. Vakıflar Bankası A.Ş. and T.C. Halk Bankası A.Ş. have been selected to represent state banking sector in Turkey and 4 private sector banks that are Türkiye Yapı ve Kredi Bankası, Akbank, Türkiye Garanti Bankası and Türkiye İş Bankası A.Ş. have been selected to represent private sector banking in the Turkish banking sector according to their percentage of assets in the Turkish banking sector.Then, their effectiveness, productivity and performance ratios have accounted by the help of 1994-2000 balance sheets and income statements that has been published by Türkiye Bankalar Birliği. In this way, that mentioned ratios have been counted for the 2 banking groups to compare and test their performance and profitability for the period of 1994-2000 years.The work is composed of 3 Chapters. In the first Chapter, theoretical information is explained about commercial banking. In the second Chapter, number of commercial banks, number of banks' branches and personnel have been explained for the private and state banks between the period of 1994-2000 years.Then, 4 state banks that are T.C. Ziraat Bankası A.Ş., T.C. Emlak Bankası A.Ş., T.C. Vakıflar Bankası A.Ş. and T.C. Halk Bankası A.Ş. have been selected to represent state banking sector in Turkey and 4 private sector banks that are Türkiye Yapı ve Kredi Bankası, Akbank, Türkiye Garanti Bankası and Türkiye İş Bankası A.Ş. have been selected to represent private sector banking in the Turkish banking sector according to their percentage of assets in the Turkish banking sector to account and compare their profitability, effectiveness and efficiency by the help of 1994-2000 balance sheets and income statements that have been published by Türkiye Bankalar Birliği.In the third and last Chapter, developments that have been realized about reinstruction program of banking sector and state banks' reinstructions have been explained.When the total amount of deposits and the total amount of loans are examined, we see that results:The private sector banks that hold 57% of the total amount of deposits, give 67% of the total amount of loans, but the state banks that hold 41% of the total amount of deposits give 30% of the total amount of loans in the Turkish banking sector. So, the ratio of the total loans to total deposits for the state banks is nearly 30%, while the same ratio is 60% for the private banks.These ratios show that state banks can hold more deposits than private banks because of the Government's full guaranty on deposits, higher interest rates, lots of branches and public organizations' deposits that are held in the state banks. So, the state banks hold 41% of the total amount of deposits, but give only 30% of the total amount of the total loans in the sector. This state explicit that the state banks use the deposits that are deposited to the state banks any different areas apart from giving loans to markets.In spite of, a part of non-performing loans are being hidden in the balance sheets of the state banks for not being obligatory for non-performing loans reserves; the loans that have been given to the Treasury and non-performing, have been written duty losses in the balance sheets, the ratio of non-performing loans to the total loans for the state banks is 9% (this ratio is 18% for T.C. Ziraat Bankası A.Ş. and 29% for T.C. Emlak Bankası A.Ş.), while the same ratio is 1% for the selected private banks.So, we can say that, state banks have been often exposed to political interventions during loans-giving duration.When the income statements of the state banks and private sector banks are examined we see that:The ratio of the interest-income to the total income is about 80% for the state banks, while the same ratio is under this percentage for the selected private sector banks. But, the ratio of the operations income (except interest-income) to the total income for the state banks is quietly under private sector banks'.When the ratio of net profits to the total assets, the ratio of net profit to the capital, the ratio of net profit to the total deposits, the ratio of net profit to the total loans are examined we see that the mentioned ratios for the state banks are lower than the private banks' and negative values for T.C. Emlak Bankası A.Ş. especially in last years. When the ratio of net interest-income to the total assets, the ratio of net interest-income to the capital, the ratio of net interest-income to the total deposits, the ratio of net interest-income to the total loans are examined we see that the mentioned ratios for the state banks are lower than the private banks' and negative values for T.C. Emlak Bankası A.Ş. especially in last years. So, it's impossible to say about profit for the state banks.The results of the analyses about state banks' place in the Turkish banking sector shows that profitability, effectiveness and efficiency of the state banks are lower than selected private sector banks'

An evaluation of inflation expectations in Turkey

Expectations of inflation play a critical role in the process of price setting in the market. Central banks closely follow developments in inflation expectations to implement a successful monetary policy. The Central Bank of the Republic of Turkey (CBRT) conducts a survey of experts and decision makers in the financial and real sectors to reveal market expectations and predictions of current and future inflation. The survey is conducted every month. This paper examines the accuracy of these survey predictions using forecast evaluation techniques. We focus on both point and sign accuracy of the predictions. Although point predictions from CBRT surveys are compared with those of autoregressive models, sign predictions are evaluated on their value to a user. We also test the predictions for bias. Unlike the empirical evidence from other economies, our results show that autoregressive models outperform most of inflation expectations in forecasting inflation. This indicates that inflation expectations have poor point forecast accuracies. However, we show that sign predictions for all inflation expectations have value to a user

Response of a 3D elastic half-space to a distributed moving load

The dynamic eect of an out of plane distributed moving load on thesurface of an elastic half-space is considered. The problem is formulatedin terms of a hyperbolic-elliptic asymptotic model for a movingload where the trajectory and the distribution of the load are taken tobe orthogonal. Steady-state equations are written in terms of a movingcoordinate system. The near-resonant solutions are, then, obtained forsub and super-Rayleigh cases taking into account the causality principle.Numerical results of displacement components are presented forvarious values of the distribution parameter

Memory Encryption for Smart Cards

Part 5: Implementations and Hardware Security 2International audienceWith the latest advances in attack methods, it has become increasingly more difficult to secure data stored on smart cards, especially on non-volatile memories (NVMs), which may store sensitive information such as cryptographic keys or program code. Lightweight and low-latency cryptographic modules are a promising solution to this problem. In this study, memory encryption schemes using counter (CTR) and XOR-Encrypt-XOR (XEX) modes of operation are adapted for the target application, and utilized using various implementations of the block ciphers AES and PRESENT. Both schemes are implemented with a block cipher-based address scrambling scheme, as well as a special write counter scheme in order to extend the lifetime of the encryption key in CTR-mode. Using the lightweight cipher PRESENT, it is possible to implement a smart card NVM encryption scheme with less than 6K gate equivalents and zero additional latency

Atypical lung involvement in a patient with systemic juvenile xanthogranuloma

Juvenile xanthogranuloma (JXG) is a non-Langerhans cell histiocytosis characterized by xanthoma-like cutaneous lesions. It is a benign condition that is generally asymptomatic. Visceral involvement is uncommon, but when present may occur in various locations and in different combinations. Pulmonary involvement has been reported as bilateral, multiple micro- or macronodular lesions. We present a 10-year-old boy with systemic (skin, lung, liver and kidney) JXG who showed lung involvement with mainly an interstitial pattern. Bilateral multiple micronodules in both lungs and mediastinal adenopathy were also present

A revisit to the plane problem for low-frequency acoustic scattering by an elastic cylindrical shell

The proposed revisit to a classical problem in fluid–structure interaction is due to an interest in the analysis of the narrow resonances corresponding to a low-frequency fluid-borne wave, inspired by modeling and design of metamaterials. In this case, numerical implementations would greatly benefit from preliminary asymptotic predictions. The normal incidence of an acoustic wave is studied for a circular cylindrical shell governed by plane strain equations in elasticity. A novel high-order asymptotic procedure is established considering for the first time all the peculiarities of the low-frequency behavior of a thin fluid-loaded cylinder. The obtained results are exposed in the form suggested by the Resonance Scattering Theory. It is shown that the pressure scattered by rigid cylinder is the best choice for a background component. Simple explicit formulae for resonant frequencies, amplitudes, and widths are presented. They support various important observations, including comparison between widths and the error of the asymptotic expansion for frequencies