目錄 |
| Foreword | xi |
| Preface | xiii |
| Notation | xvii |
1. | Boolean Functions | 1 |
| Introduction | 1 |
1.1. | Definitions | 1 |
1.2. | Algebraic normal form | 3 |
1.3. | Boolean cube and Hamming distance | 4 |
1.4. | Extended affinely equivalent functions | 6 |
1.5. | Walsh-Hadamard transform | 7 |
1.6. | Finite field and boolean functions | 8 |
1.7. | Trace function | 9 |
1.8. | Polynomial representation of a boolean function | 11 |
1.9. | Trace representation of a boolean function | 11 |
1.10. | Monomial boolean functions | 14 |
2. | Bent Functions: An Introduction | 17 |
| Introduction | 17 |
2.1. | Definition of a nonlinearity | 17 |
2.2. | Nonlinearity of a random boolean function | 18 |
2.3. | Definition of a bent function | 18 |
2.4. | If n is odd? | 20 |
2.5. | Open problems | 21 |
2.6. | Surveys | 23 |
3. | History of Bent Functions | 25 |
| Introduction | 25 |
3.1. | Oscar Rothaus | 25 |
3.2. | V.A. Eliseev and O.P. Stepchenkov | 26 |
3.3. | From the 1970s to the present | 28 |
4. | Applications of Bent Functions | 31 |
| Introduction | 31 |
4.1. | Cryptography: linear cryptanalysis and boolean functions | 31 |
4.2. | Cryptography: one historical example | 32 |
4.3. | Cryptography: bent functions in CAST | 34 |
4.4. | Cryptography: bent functions in Grain | 35 |
4.5. | Cryptography: bent functions in HAVAL | 36 |
4.6. | Hadamard matrices and graphs | 37 |
4.7. | Links to coding theory | 38 |
4.8. | Bent sequences | 39 |
4.9. | Mobile networks, CDMA | 40 |
4.10. | Remarks | 42 |
5. | Properties of Bent Functions | 43 |
| Introduction | 43 |
5.1. | Degree of a bent function | 43 |
5.2. | Affine transformations of bent functions | 44 |
5.3. | Rank of a bent function | 45 |
5.4. | Dual bent functions | 45 |
5.5. | Other properties | 46 |
6. | Equivalent Representations of Bent Functions | 49 |
| Introduction | 49 |
6.1. | Hadamard matrices | 49 |
6.2. | Difference sets | 49 |
6.3. | Designs | 50 |
6.4. | Linear spreads | 50 |
6.5. | Sets of subspaces | 51 |
6.6. | Strongly regular graphs | 52 |
6.7. | Bent rectangles | 52 |
7. | Bent Functions with a Small Number of Variables | 55 |
| Introduction | 55 |
7.1. | Two and four variables | 55 |
7.2. | Six variables | 56 |
7.3. | Eight variables | 59 |
7.4. | Ten and more variables | 60 |
7.5. | Algorithms for generation of bent functions | 61 |
7.6. | Concluding remarks | 62 |
8. | Combinatorial Constructions of Bent Functions | 63 |
| Introduction | 63 |
8.1. | Rothaus's iterative construction | 63 |
8.2. | Maiorana-McFarland class | 64 |
8.3. | Partial spreads: PS+, PS-- | 65 |
8.4. | Dillon's bent functions: PSap | 66 |
8.5. | Dobbertin's construction | 67 |
8.6. | More iterative constructions | 67 |
8.7. | Minterm iterative constructions | 68 |
8.8. | Bent iterative functions: BI | 69 |
8.9. | Other constructions | 72 |
9. | Algebraic Constructions of Bent Functions | 73 |
| Introduction | 73 |
9.1. | An algebraic approach | 73 |
9.2. | Bent exponents: general properties | 74 |
9.3. | Gold bent functions | 75 |
9.4. | Dillon exponent | 76 |
9.5. | Kasami bent functions | 76 |
9.6. | Canteaut-Leander bent functions (MF-1) | 78 |
9.7. | Canteaut-Charpin-Kuyreghyan bent functions (MF-2) | 78 |
9.8. | Niho exponents | 79 |
9.9. | General algebraic approach | 80 |
9.10. | Other constructions | 80 |
10. | Bent Functions and Other Cryptographic Properties | 81 |
| Introduction | 81 |
10.1. | Cryptographic criteria | 81 |
10.2. | High degree and balancedness | 82 |
10.3. | Correlation immunity and resiliency | 82 |
10.4. | Algebraic immunity | 83 |
10.5. | Vectorial bent functions, almost bent functions, and almost perfect nonlinear functions | 85 |
11. | Distances Between Bent Functions | 89 |
| Introduction | 89 |
11.1. | The minimal possible distance between bent functions | 89 |
11.2. | Classification of bent functions at the minimal distance from the quadratic bent function | 90 |
11.3. | Upper bound for the number of bent functions at the minimal distance from an arbitrary bent function | 93 |
11.4. | Bent functions at the minimal distance from a McFarland bent function | 94 |
11.5. | Locally metrically equivalent bent functions | 94 |
11.6. | The graph of minimal distances of bent functions | 95 |
12. | Automorphisms of the Set of Bent Functions | 97 |
| Introduction | 97 |
12.1. | Preliminaries | 97 |
12.2. | Shifts of the class of bent functions | 98 |
12.3. | Duality between definitions of bent and affine functions | 102 |
12.4. | Automorphisms of the set of bent functions | 104 |
12.5. | Metrically regular sets | 105 |
13. | Bounds on the Number of Bent Functions | 107 |
| Introduction | 107 |
13.1. | Preliminaries | 107 |
13.2. | The number of bent functions for small n | 108 |
13.3. | Upper bounds | 108 |
13.4. | Direct lower bounds | 111 |
13.5. | Iterative lower bounds | 112 |
13.6. | Lower bound from the bent iterative functions | 114 |
13.7. | Testing of the lower bound for small n | 118 |
13.8. | Asymptotic problem and hypotheses | 120 |
14. | Bent Decomposition Problem | 123 |
| Introduction | 123 |
14.1. | Preliminaries | 123 |
14.2. | Partial results | 124 |
14.3. | Boolean function as the sum of a constant number of bent functions | 125 |
14.4. | Any cubic boolean function in eight variables is the sum of at most four bent functions | 127 |
14.5. | Decomposition of dual bent functions | 128 |
15. | Algebraic Generalizations of Bent Functions | 133 |
| Introduction | 133 |
15.1. | Preliminaries | 133 |
15.2. | The q-valued bent functions | 134 |
15.3. | The p-ary bent functions | 137 |
15.4. | Bent functions over a finite field | 139 |
15.5. | Bent functions over quasi-frobenius local rings | 141 |
15.6. | Generalized boolean bent functions (of Schmidt) | 141 |
15.7. | Bent functions from a finite abelian group into the set of complex numbers on the unit circle | 144 |
15.8. | Bent functions from a finite abelian group into a finite abelian group | 145 |
15.9. | Non-abelian bent functions | 147 |
15.10. | Vectorial G-bent functions | 148 |
15.11. | Multidimensional bent functions on a finite abelian group | 149 |
16. | Combinatorial Generalizations of Bent Functions | 151 |
| Introduction | 151 |
16.1. | Symmetric bent functions | 151 |
16.2. | Homogeneous bent functions | 152 |
16.3. | Rotation-symmetric bent functions | 152 |
16.4. | Normal bent functions | 155 |
16.5. | Self-dual and anti-self-dual bent functions | 156 |
16.6. | Partially defined bent functions | 158 |
16.7. | Plateaued functions | 158 |
16.8. | Z-bent functions | 159 |
16.9. | Negabent functions, bent4-functions, and l-bent functions | 160 |
17. | Cryptographic Generalizations of Bent Functions | 163 |
| Introduction | 163 |
17.1. | Semibent functions (near-bent functions) | 163 |
17.2. | Balanced (semi-) bent functions | 165 |
17.3. | Partially bent functions | 166 |
17.4. | Hyperbent functions | 168 |
17.5. | Bent functions of higher order | 171 |
17.6. | k-bent functions | 172 |
| References | 175 |
| Index | 197 |