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Authenticated Encryption for Memory Constrained Devices Authenticated Encryption for Memory Constrained Devices By Megha Agrawal A thesis submitted in partial fulfillment for the degree of Doctor of Philosophy in Computer Science & Engineering to the Indraprastha Institute of Information Technology, Delhi (IIIT-Delhi) Supervisors: Dr. Donghoon Chang (IIIT Delhi) Dr. Somitra Sanadhya (IIT Jodhpur) September 2020 Certificate This is to certify that the thesis titled - \Authenticated Encryption for Memory Constrained Devices" being submitted by Megha Agrawal to Indraprastha Institute of Information Technology, Delhi, for the award of the degree of Doctor of Philosophy, is an original research work carried out by her under our supervision. In our opinion, the thesis has reached the standards fulfilling the requirements of the regulations relating to the degree. The results contained in this thesis have not been submitted in part or full to any other university or institute for the award of any degree/diploma. Dr. Donghoon Chang September, 2020 Department of Computer Science Indraprastha Institute of Information Technology, Delhi New Delhi, 110020 ii To my family Acknowledgments Firstly, I would like to express my sincere gratitude to my advisor Dr. Donghoon Chang for the continuous support of my Ph.D study and related research, for his patience, motivation, and immense knowledge. His guidance helped me in all the time of research and writing of this thesis. I could not have imagined having a better advisor and mentor for my Ph.D study. I also express my sincere gratitude to my esteemed co-advisor, Dr. Somitra Sanadhya, who has helped me immensely throughout my Ph.D. life. I thank my fellow labmates for the stimulating discussions, and for all the fun we have had in during these years. I would like to thank my co-author Jinkeon Kang, for helping me in my work. I would also like to thank all my friends, especially Tarun for their help and cooperation that always kept my spirits high. Their company made my graduate life a memorable one. I would also like to forward my gratitude to Tata Consultancy Services (TCS), India for awarding me the prestigious TCS fellowship for my full PhD period. Without their generous sponsorship, I would not have been able to travel around the world to attend a number of academic events, including conferences, workshops and summer schools. I would also like to thank all the reviewers for providing valuable feedback to improve the quality of thesis. Of course, none of this would be possible without my family who worked hard to sharpen my skills and have always encouraged and supported me to go further in life. Above all, I am grateful to the Almighty, who showered the opportunity, blessings and moral courage on me to complete this dissertation. iv Contents 1 Introduction 3 1.1 Motivation . .3 1.2 Outline of the thesis . .4 2 Basics 6 2.1 Cryptographic Goals . .6 2.2 Communication Model . .7 2.2.1 Generic Attacks on Communication Model . .8 2.3 Basic settings of Cryptography . .9 2.4 Symmetric Key Cryptosystem . 11 2.4.1 Confidentiality . 11 2.4.2 Authenticity . 11 2.5 Providing Confidentiality . 12 2.5.1 Block Ciphers . 12 2.5.2 Stream Ciphers . 13 2.6 Providing Authenticity . 13 2.6.1 Hash Function . 13 2.6.2 Message Authentication Code (MAC) . 14 3 Authenticated Encryption 15 3.1 Introduction . 15 3.2 Necessity and Usage . 15 3.3 Definition . 17 3.4 AE Classification . 19 3.5 Conventional AE Schemes . 20 3.5.1 Generic Compositions . 21 3.5.2 Non-generic Compositions . 24 3.6 Dedicated schemes . 31 3.6.1 Integrity aware parallelizable mode: IAPM . 31 3.6.2 Offset CodeBook mode : OCB . 33 3.6.3 SpongeWrap . 34 3.7 Comparison of AE schemes . 35 v 3.8 Security Notions for Authenticated Encryption . 36 3.8.1 Privacy . 36 3.8.2 Authenticity . 37 3.9 Various other Security Notions . 38 3.9.1 Releasing Unverified Plaintext (RUP) . 38 3.9.2 Robust Authenticated Encryption (RAE) . 40 4 Preliminaries 41 4.1 Provable Security . 41 4.2 Adversary Models . 42 4.2.1 Standard Model . 42 4.2.2 Random Oracle Model . 42 4.2.3 Ideal Cipher Model . 42 4.3 Random Oracle . 43 4.4 Proof Techniques . 43 4.4.1 Game Playing Framework . 44 4.4.2 Coefficients H Technique . 45 5 Authenticated Encryption Using Cryptographic Module 47 5.1 Cryptographic Module . 48 5.2 Operational Environment . 49 6 Related Work 51 6.1 Intermediate Tag . 51 6.2 Remotely Keyed Authenticated Encryption . 52 6.2.1 Decrypt-Then-Mask Protocol . 54 6.3 Releasing Unverified Plaintext . 55 7 sp-AELM: Sponge based Authenticated Encryption for Limited Memory Devices 57 7.1 Sponge Function . 58 7.2 Description of sp-AELM . 58 7.2.1 Encryption . 59 7.2.2 Decryption and Verification . 61 7.3 Definitions . 61 7.4 Security Proof . 63 7.4.1 Privacy . 63 7.4.2 Authenticity . 66 7.5 More variants of sp-AELM . 67 7.6 Comparison . 68 7.7 Summary . 69 vi 8 Analysis of Sponge based Submissions in CAESAR using Limited Memory Technique 79 8.1 ARTEMIA [49] . 79 8.2 ASCON [25] . 80 8.3 ICEPOLE [62] . 80 8.4 STRIBOB [57] . 81 8.5 Π-Cipher [29] . 81 8.6 PRIMATE [36] . 82 8.7 NORX [50] . 83 8.8 Ketje [41] . 83 8.9 Keyak [42] . 84 8.10 Summary . 84 9 dAELM: Deterministic Authenticated Encryption for Limited Memory Devices 85 9.1 Preliminaries . 86 9.2 Specifications of dAELM . 87 9.2.1 An Operational Scenario For the Proposed Scheme . 87 9.2.2 Description . 88 9.3 Security Results for the New Construction dAELM . 90 9.3.1 Privacy . 90 9.3.2 Authenticity . 93 9.4 Comparison . 95 9.5 Software Implementation . 96 9.6 Discussion . 98 9.7 Summary . 99 10 RSAEB: Modified SAEB Secure in RUP Settings 108 10.1 Authenticated Encryption . 109 10.1.1 Conventional Security Models . 110 10.1.2 RUP Security Model . 110 10.2 Generalized AE Security in RUP Settings . 111 10.2.1 Reductions from AERUP . 112 10.3 Description of SAEB . 113 10.4 PA1 Attack on SAEB . 113 10.5 RSAEB v1 . 114 10.6 RSAEB v2 . 117 10.7 Security of RSAEB v1 . 119 10.7.1 Proof . 119 10.7.2 Limitation . ..
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