Part 1 Cryptanalysis of Symmetric-key Algorithms 1

Chapter 1 Differential Cryptanalysis 3
Henri Gilbert and Jérémy Jean

1.1. Statistical attacks on block ciphers: preliminaries 4

1.2. Principle of differential cryptanalysis and application to DES 7

1.2.1. Differential transitions and differential characteristics 7

1.2.2. Derivation of non-trivial differential characteristics 10

1.2.3. Leveraging characteristics to mount a key-recovery attack 14

1.3. Some refinements and generalizations 18

1.3.1. Differential effect 18

1.3.2. Truncated differentials 19

1.4. Design strategies and evaluation 20

1.4.1 Case of the AES 21

1.4.2. Automated analysis 23

1.5. Further notes and references 23

1.6. References 26

Chapter 2 Linear Cryptanalysis 29
Kaisa Nyberg and Antonio Flórez-Gutiérrez

2.1. History 29

2.2. Correlation and linear hull 30

2.3. Multidimensional linear approximation 31

2.4. Walsh-Hadamard transform 32

2.5. Linear approximation of an iterative block cipher 32

2.6. Matsui’s Algorithm 1 type of key recovery 33

2.7. Matsui’s Algorithm 2 type of key recovery 34

2.8. Searching for linear approximations and estimating correlations 35

2.9. Speeding up key recovery 36

2.10. Key-recovery distinguisher 38

2.11. Classical model of Algorithm 2 39

2.12. Algorithm 2 with distinct known plaintext and randomized key 40

2.13. Multiple linear approximations 40

2.14. Multidimensional linear cryptanalysis 42

2.15. References 43

Chapter 3 Impossible Differential Cryptanalysis 47
Christina Boura and María Naya-Plasencia

3.1. Finding impossible differentials 48

3.2. Key recovery 49

3.2.1. Data, time and memory complexities 50

3.3. Some improvements 52

3.3.1. Early abort technique 52

3.3.2. Multiple impossible differentials or multiple extension paths 53

3.4. Applications 54

3.5. References 54

Chapter 4 Zero-Correlation Cryptanalysis 57
Vincent Rijmen

4.1. Correlation and linear cryptanalysis 57

4.1.1. Correlation matrix 57

4.1.2. Linear trails and linear hulls 58

4.1.3. Approximations of linear functions 59

4.1.4. Computing the correlations over a permutation 60

4.2. Attacks using a linear hull with correlation zero 60

4.2.1. Correlation zero in random permutations 61

4.2.2. Distinguisher 61

4.2.3. Reducing the data complexity 62

4.3. Linear hulls with correlation zero 62

4.3.1. Feistel ciphers 63

4.3.2. AES 64

4.3.3 Extended result on AES 64

4.4. References 64

Chapter 5 Differential-Linear Cryptanalysis 67
Yosuke Todo

5.1. Brief introduction of differential-linear attacks 67

5.2. How to estimate correlations of a differential-linear distinguisher 69

5.3. On the key recovery 71

5.4. State of the art for differential-linear attacks 72

5.4.1. Differential-linear connecting table 72

5.4.2. Three techniques to improve differential-linear attacks 73

5.5. References 76

Chapter 6 Boomerang Cryptanalysis 77
Ling Song

6.1. Basic boomerang attack 77

6.2. Variants and refinements 79

6.3. Tricks and failures 80

6.4. Formalize the dependency 83

6.5. References 86

Chapter 7 Meet-in-the-Middle Cryptanalysis 89
Brice Minaud

7.1. Introduction 89

7.2. Basic meet-in-the-middle framework 90

7.2.1. The 2DES attack 90

7.2.2. Algorithmic framework 91

7.2.3. Complexity analysis and memory usage 92

7.3. Meet-in-the-middle techniques 94

7.3.1. Filtering 94

7.3.2. Splice-and-cut 96

7.3.3. Bicliques 97

7.4. Automatic tools 98

7.5. References 98

Chapter 8 Meet-in-the-Middle Demirci-Selçuk Cryptanalysis 101
Patrick Derbez

8.1. Original Demirci-Selçuk attack 101

8.2. Improvements 103

8.2.1. Data/time/memory trade-off 104

8.2.2. Difference instead of value 104

8.2.3. Multiset 105

8.2.4. Linear combinations 105

8.2.5. Differential enumeration technique 106

8.3. Finding the best attacks 108

8.3.1. Tools 108

8.3.2. Results 109

8.4. References 109

Chapter 9 Invariant Cryptanalysis 111
Christof Beierle

9.1. Introduction 111

9.2. Invariants for permutations and block ciphers 112

9.2.1. Invariant subspaces 113

9.2.2. Quadratic invariants 117

9.3. On design criteria to prevent attacks based on invariants 117

9.4. A link to linear approximations 119

9.5. References 121

Chapter 10 Higher Order Differentials, Integral Attacks and Variants 123
Anne Canteaut

10.1. Integrals and higher order derivatives 123

10.2. Algebraic degree of an iterated function 126

10.3. Division property 128

10.4. Attacks based on integrals 130

10.4.1. Distinguishers 130

10.4.2. Attacks 130

10.5. References 131

Chapter 11 Cube Attacks and Distinguishers 133
Itai Dinur

11.1. Cube attacks and cube testers 133

11.1.1. Terminology 134

11.1.2. Main observation 135

11.1.3. The basic cube attack 136

11.1.4. The preprocessing phase on cube attacks 137

11.1.5. Cube testers 138

11.1.6. Applications 139

11.2. Conditional differential attacks and dynamic cube attacks 140

11.2.1. Conditional differential attacks 140

11.2.2. Dynamic cube attacks 140

11.2.3. A toy example 140

11.3. References 141

Chapter 12 Correlation Attacks on Stream Ciphers 143
Thomas Johansson

12.1. Correlation attacks on the nonlinear combination generator 144

12.2. Correlation attacks and decoding linear codes 145

12.3. Fast correlation attacks 146

12.3.1. Fast correlation attacks and low weight feedback polynomials 147

12.3.2. Finding low weight multiples of the feedback polynomial 148

12.3.3. Fast correlation attacks by reducing the code dimension 150

12.4. Generalizing fast correlation attacks 151

12.4.1. The E0 stream cipher 151

12.4.2. The A5/1 stream cipher 152

12.5. References 153

Chapter 13 Addition, Rotation, XOR 155
Léo Perrin

13.1. What is ARX? 155

13.1.1. Structure of an ARX-based primitive 156

13.1.2. Development of ARX 156

13.2. Understanding modular addition 157

13.2.1. Expressing modular addition in Fⁿ₂ 158

13.2.2. Cryptographic properties of modular addition 158

13.3. Analyzing ARX-based primitives 160

13.3.1. Searching for differential and linear trails 160

13.3.2. Proving security against differential and linear attacks 161

13.3.3. Other cryptanalysis techniques 162

13.4. References 163

Chapter 14 SHA-3 Contest Related Cryptanalysis 167
Yu S Asaki

14.1. Chapter overview 167

14.2. Differences between attacks against keyed and keyless primitives 168

14.3. Rebound attack 169

14.3.1. Basic strategy of the rebound attack 169

14.3.2. Rebound attack against AES-like structures 171

14.4. Improving rebound attacks with Super-Sbox 173

14.5. References for further reading about rebound attacks 175

14.6. Brief introduction of other cryptanalysis 176

14.6.1. Internal differential cryptanalysis 176

14.6.2. Rotational cryptanalysis 177

14.7. References 177

Chapter 15 Cryptanalysis of SHA-1 181
Marc Stevens

15.1. Design of SHA-1 181

15.2. SHA-1 compression function 182

15.3. Differential analysis 184

15.4. Near-collision attacks 184

15.5. Near-collision search 185

15.6. Message expansion differences 186

15.7. Differential trail 187

15.8. Local collisions 187

15.9. Disturbance vector 188

15.10. Disturbance vector selection 189

15.11. Differential trail construction 190

15.12. Message modification techniques 190

15.13. Overview of published collision attacks 191

15.14. References 192

Part 2 Future Directions 195

Chapter 16 Lightweight Cryptography 197
Meltem Sönmez Turan

16.1. Lightweight cryptography standardization efforts 197

16.2. Desired features 198

16.3. Design approaches in lightweight cryptography 200

16.4. References 202

Chapter 17 Post-Quantum Symmetric Cryptography 203
María Naya-Plasencia

17.1. Different considered models 204

17.1.1. With respect to the queries 204

17.1.2. With respect to memory 205

17.2. On Simon’s and Q2 attacks 206

17.2.1. Off-line Simon’s attack 207

17.3. Quantizing classical attacks in Q 1 207

17.3.1. About collisions 207

17.4. On the design of quantum-safe primitives 208

17.5. Perspectives and conclusion 209

17.5.1. About losing the quantum and classical surname 209

17.5.2. No panic 209

17.6. References 209

Chapter 18 New Fields in Symmetric Cryptography 215
Léo Perrin

18.1. Arithmetization-oriented symmetric primitives (ZK proof systems) 216

18.1.1. The current understanding of this new language 217

18.1.2. The first attempts 218

18.1.3. Cryptanalysis 219

18.2. Symmetric ciphers for hybrid homomorphic encryption 220

18.2.1. The current understanding of this new language 221

18.2.2. First design strategies 221

18.3. Parting thoughts 223

18.4. References 223

Chapter 19 Deck-function-based Cryptography 227
Joan Daemen

19.1. Block-cipher centric cryptography 227

19.2. Permutation-based cryptography 227

19.3. The problem of the random permutation security model 228

19.4. Deck functions 228

19.5. Modes of deck functions and instances 229

19.6. References 230

List of Authors 231

Index 233

Summary of Volume 1 239