Lecture 17 November 1, 2017
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Etsi Gr Qsc 001 V1.1.1 (2016-07)
ETSI GR QSC 001 V1.1.1 (2016-07) GROUP REPORT Quantum-Safe Cryptography (QSC); Quantum-safe algorithmic framework 2 ETSI GR QSC 001 V1.1.1 (2016-07) Reference DGR/QSC-001 Keywords algorithm, authentication, confidentiality, security ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N° 348 623 562 00017 - NAF 742 C Association à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N° 7803/88 Important notice The present document can be downloaded from: http://www.etsi.org/standards-search The present document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx If you find errors in the present document, please send your comment to one of the following services: https://portal.etsi.org/People/CommiteeSupportStaff.aspx Copyright Notification No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm except as authorized by written permission of ETSI. -
On the Efficiency of the Lamport Signature Scheme
Technical Sciences 275 ON THE EFFICIENCY OF THE LAMPORT SIGNATURE SCHEME Daniel ZENTAI Óbuda University, Budapest, Hungary [email protected] ABSTRACT Post-quantum (or quantum-resistant) cryptography refers to a set of cryptographic algorithms that are thought to remain secure even in the world of quantum computers. These algorithms are usually considered to be inefficient because of their big keys, or their running time. However, if quantum computers became a reality, security professionals will not have any other choice, but to use these algorithms. Lamport signature is a hash based one-time digital signature algorithm that is thought to be quantum-resistant. In this paper we will describe some simulation results related to the efficiency of the Lamport signature. KEYWORDS: digital signature, post-quantum cryptography, hash functions 1. Introduction This paper is organized as follows. Although reasonable sized quantum After this introduction, in chapter 2 we computers do not exist yet, post quantum describe some basic concepts and definition cryptography (Bernstein, 2009) became an related to the security of hash functions. important research field recently. Indeed, Also, we describe the Lamport one-time we have to discover the properties of these signature algorithm. In chapter 3 we algorithms before quantum computers expound our simulation results related to become a reality, namely suppose that we the efficiency of the Lamport signature. use the current cryptographic algorithms for The last chapter summarizes our work. x more years, we need y years to change the most widely used algorithms and update 2. Preliminaries our standards, and we need z years to build In this chapter the basic concepts and a quantum-computer. -
Outline One-Time Signatures One-Time Signatures Lamport's
Advanced Security Outline § One-Time Signatures Constructions • Lamport’s signature and Key Management • Improved signature constructions • Merkle-Winternitz Signature § Efficient Authenticators (amortize signature) Class 16 • One-way chains (self-authenticating values) • Chained hashes • Merkle Hash Trees § Applications • Efficient short-lived certificates, S/Key • Untrusted external storage • Stream signatures (Gennaro, Rohatgi) § Zhou & Haas’s key distribution One-Time Signatures One-Time Signatures § Use one -way functions without trapdoor § Challenge: digital signatures expensive § Efficient for signature generation and for generation and verification verification § Caveat: can only use one time § Goal: amortize digital signature § Example: 1-bit one-time signature • P0, P1 are public values (public key) • S0, S1 are private values (private key) S0 P0 S0 S0’ P S1 P1 S1 S1’ Lamport’s One-Time Signature Improved Construction I § Uses 1-bit signature construction to sign multiple bits § Uses 1-bit signature construction to sign multiple bits Sign 0 S0 S0’ S0’’ S0* Private values S0 S0’ S0’’ S0* c0 c0’ c0* P0 P0’ P0’’ P0* … … … Public values P0 P0’ P0’’ P0* p0 p0’ p0* P1 P1’ P1’’ P1* Bit 0 Bit 1 Bit 2 Bit n Bit 0 Bit 1 Bit log(n) Sign 1 S1 S1’ S1’’ S1* Private values Sign message Checksum bits: encode Bit 0 Bit 1 Bit 2 Bit n # of signature bits = 0 1 Improved Construction II Merkle-Winternitz Construction § Intuition: encode sum of checksum chain § Lamport signature has high overhead Signature S0 S1 S2 S3 § Goal: reduce size of public -
A Survey on Post-Quantum Cryptography for Constrained Devices
International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 11 (2019) pp. 2608-2615 © Research India Publications. http://www.ripublication.com A Survey on Post-Quantum Cryptography for Constrained Devices Kumar Sekhar Roy and Hemanta Kumar Kalita Abstract Quantum Computer” [1]. Shor’s algorithm can solve integer The rise of Quantum computers in the recent years have given factorization problem as well as discrete logarithm problem a major setback to classical and widely used cryptography used by RSA as well as ECC respectively in polynomial time schemes such as RSA(Rivest-Shamir-Adleman) Algorithm using a sufficiently large Quantum Computer. Thus making the and ECC (Elliptic Curve Cryptography). RSA and ECC use of cryptosystems based on integer factorization problem as depends on integer factorization problem and discrete well as discrete logarithm problem obsolete. This current logarithm problem respectively, which can be easily solved by advances has raised a genuine need for development of Quantum Computers of sufficiently large size running the cryptosystems which could serve as viable replacement for infamous Shor’s Algorithm. Therefore cryptography schemes traditionally used cryptosystems which are vulnerable to which are difficult to solve in both traditional as well as quantum computer based attacks. Since the arrival of IoT, the Quantum Computers need to be evaluated. In our paper we Cyber security scenario has entirely shifted towards security provide a rigorous survey on Post-Quantum Cryptography schemes which are lightweight in terms of computational schemes and emphasize on their applicability to provide complexity, power consumption, memory consumption etc. security in constrained devices. We provide a detailed insight This schemes also need to be secure against all known attacks. -
IB Case Study Vocabulary a Local Economy Driven by Blockchain (2020) Websites
IB Case Study Vocabulary A local economy driven by blockchain (2020) Websites Merkle Tree: https://blockonomi.com/merkle-tree/ Blockchain: https://unwttng.com/what-is-a-blockchain Mining: https://www.buybitcoinworldwide.com/mining/ Attacks on Cryptocurrencies: https://blockgeeks.com/guides/hypothetical-attacks-on-cryptocurrencies/ Bitcoin Transaction Life Cycle: https://ducmanhphan.github.io/2018-12-18-Transaction-pool-in- blockchain/#transaction-pool 51 % attack - a potential attack on a blockchain network, where a single entity or organization can control the majority of the hash rate, potentially causing a network disruption. In such a scenario, the attacker would have enough mining power to intentionally exclude or modify the ordering of transactions. Block - records, which together form a blockchain. ... Blocks hold all the records of valid cryptocurrency transactions. They are hashed and encoded into a hash tree or Merkle tree. In the world of cryptocurrencies, blocks are like ledger pages while the whole record-keeping book is the blockchain. A block is a file that stores unalterable data related to the network. Blockchain - a data structure that holds transactional records and while ensuring security, transparency, and decentralization. You can also think of it as a chain or records stored in the forms of blocks which are controlled by no single authority. Block header – main way of identifying a block in a blockchain is via its block header hash. The block hash is responsible for block identification within a blockchain. In short, each block on the blockchain is identified by its block header hash. Each block is uniquely identified by a hash number that is obtained by double hashing the block header with the SHA256 algorithm. -
Universal Leaky Random Oracle
Universal Leaky Random Oracle Guangjun Fan1, Yongbin Zhou2, Dengguo Feng1 1 Trusted Computing and Information Assurance Laboratory,Institute of Software,Chinese Academy of Sciences,Beijing,China [email protected] , [email protected] 2 State Key Laboratory of Information Security,Institute of Information Engineering,Chinese Academy of Sciences,Beijing,China [email protected] Abstract. Yoneyama et al. introduces the Leaky Random Oracle Model at ProvSec2008 to capture the leakages from the hash list of a hash func- tion used by a cryptography construction due to various attacks caused by sloppy usages or implementations in the real world. However, an im- portant fact is that such attacks would leak not only the hash list, but also other secret states (e.g. the secret key) outside the hash list. There- fore, the Leaky Random Oracle Model is very limited in the sense that it considers the leakages from the hash list alone, instead of taking into con- sideration other possible leakages from secret states simultaneously. In this paper, we present an augmented model of the Leaky Random Oracle Model. In our new model, both the secret key and the hash list can be leaked. Furthermore, the secret key can be leaked continually during the whole lifecycle of the cryptography construction. Hence, our new model is more universal and stronger than the Leaky Random Oracle Model and some other leakage models (e.g. only computation leaks model and memory leakage model). As an application example, we also present a public key encryption scheme which is provably IND-CCA secure in our new model. -
PGP Command Line User Guide
PGP Command Line User Guide Last updated: July 2020 Copyright statement Broadcom, the pulse logo, Connecting everything, and Symantec are among the trademarks of Broadcom. Copyright © 2020 Broadcom. All Rights Reserved. The term “Broadcom” refers to Broadcom Inc. and/or its subsidiaries. For more information, please visit www.broadcom.com. Broadcom reserves the right to make changes without further notice to any products or data herein to improve reliability, function, or design. Information furnished by Broadcom is believed to be accurate and reliable. However, Broadcom does not assume any liability arising out of the application or use of this information, nor the application or use of any product or circuit described herein, neither does it convey any license under its patent rights nor the rights of others. Contents About PGP Command Line 1 Important Concepts 1 Technical Support 2 Installing 5 Install Location 5 Installing on AIX 6 Installing on AIX 6 Changing the Home Directory on AIX 7 Uninstalling on AIX 7 Installing on HP-UX 8 Installing on HP-UX 8 Changing the Home Directory on HP-UX 9 Installing to a Non-Default Directory on HP-UX 9 Uninstalling on HP-UX 9 Installing on macOS 10 Installing on macOS 10 Changing the Home Directory on macOS 10 Uninstalling on macOS 11 Installing on Red Hat Enterprise Linux, SLES, or Fedora Core 11 Installing on Red Hat Enterprise Linux or Fedora Core 11 Changing the Home Directory on Linux or Fedora Core 12 Uninstalling on Linux or Fedora Core 12 Installing on Oracle Solaris 13 Installing on Oracle -
Applications of SKREM-Like Symmetric Key Ciphers
Applications of SKREM-like symmetric key ciphers Mircea-Adrian Digulescu1;2 February 2021 1Individual Researcher, Worldwide 2Formerly: Department of Computer Science, Faculty of Mathematics and Computer Science, University of Bucharest, Romania [email protected], [email protected], [email protected] Abstract In a prior paper we introduced a new symmetric key encryption scheme called Short Key Random Encryption Machine (SKREM), for which we claimed excellent security guarantees. In this paper we present and briey discuss some of its applications outside conventional data encryption. These are Secure Coin Flipping, Cryptographic Hashing, Zero-Leaked-Knowledge Authentication and Autho- rization and a Digital Signature scheme which can be employed on a block-chain. We also briey recap SKREM-like ciphers and the assumptions on which their security are based. The above appli- cations are novel because they do not involve public key cryptography. Furthermore, the security of SKREM-like ciphers is not based on hardness of some algebraic operations, thus not opening them up to specic quantum computing attacks. Keywords: Symmetric Key Encryption, Provable Security, One Time Pad, Zero Knowledge, Cryptographic Commit Protocol, Secure Coin Flipping, Authentication, Authorization, Cryptographic Hash, Digital Signature, Chaos Machine 1 Introduction So far, most encryption schemes able to serve Secure Coin Flipping, Zero-Knowledge Authentication and Digital Signatures, have relied on public key cryptography, which in turn relies on the hardness of prime factorization or some algebraic operation in general. Prime Factorization, in turn, has been shown to be vulnerable to attacks by a quantum computer (see [1]). In [2] we introduced a novel symmetric key encryption scheme, which does not rely on hardness of algebraic operations for its security guarantees. -
Speeding-Up Verification of Digital Signatures Abdul Rahman Taleb, Damien Vergnaud
Speeding-Up Verification of Digital Signatures Abdul Rahman Taleb, Damien Vergnaud To cite this version: Abdul Rahman Taleb, Damien Vergnaud. Speeding-Up Verification of Digital Signatures. Journal of Computer and System Sciences, Elsevier, 2021, 116, pp.22-39. 10.1016/j.jcss.2020.08.005. hal- 02934136 HAL Id: hal-02934136 https://hal.archives-ouvertes.fr/hal-02934136 Submitted on 27 Sep 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Speeding-Up Verification of Digital Signatures Abdul Rahman Taleb1, Damien Vergnaud2, Abstract In 2003, Fischlin introduced the concept of progressive verification in cryptog- raphy to relate the error probability of a cryptographic verification procedure to its running time. It ensures that the verifier confidence in the validity of a verification procedure grows with the work it invests in the computation. Le, Kelkar and Kate recently revisited this approach for digital signatures and pro- posed a similar framework under the name of flexible signatures. We propose efficient probabilistic verification procedures for popular signature schemes in which the error probability of a verifier decreases exponentially with the ver- ifier running time. We propose theoretical schemes for the RSA and ECDSA signatures based on some elegant idea proposed by Bernstein in 2000 and some additional tricks. -
Handling the State of Hash-Based Signatures
Let Live and Let Die — Handling the State of Hash-based Signatures Stefan-Lukas Gazdag1, Denis Butin2, and Johannes Buchmann2 1 genua mbh, Germany [email protected] 2 TU Darmstadt, Germany {dbutin,buchmann}@cdc.informatik.tu-darmstadt.de Abstract. Real-world use of digital signatures currently relies on algo rithms that will be broken once quantum computers become available. Quantum-safe alternatives exist; in particular, hash-based schemes offer adequate performance and security and are seen as a fitting solution for post-quantum signatures. Unfortunately, they are not used at large because practical hurdles have not yet been overcome. In particular, their reliance on one-time signing keys makes it necessary to carefully keep track of a key index. We present strategies for handling the state of hash- based signatures for different use cases, ranging from infrequent software update authentication to high-frequency TLS connection initialization. Keywords: Digital signatures, Hash-based, Integration 1 Motivation Digital signatures are massively used online, notably for authentication, integrity checking and non-repudiation. The digital signature algorithms most commonly used in practice — RSA, DSA and ECDSA — rely on hardness assumptions about number theoretic problems, namely composite integer factorisation and the computation of discrete logarithms. In light of Shor’s [19] algorithm, these arithmetical problems would be broken in the presence of quantum computing. While quantum computers are not yet available, their development is occurring at a swift pace [18]. However, post-quantum cryptography [3] provides a variety of quantum-resistant alternatives to classical digital signature schemes. Hash- based (or Merkle) signatures are one of the most promising of these alternatives and have received a lot of attention lately. -
Secure Signatures and Chosen Ciphertext Security in a Quantum Computing World∗
Secure Signatures and Chosen Ciphertext Security in a Quantum Computing World∗ Dan Boneh Mark Zhandry Stanford University fdabo,[email protected] Abstract We initiate the study of quantum-secure digital signatures and quantum chosen ciphertext security. In the case of signatures, we enhance the standard chosen message query model by allowing the adversary to issue quantum chosen message queries: given a superposition of messages, the adversary receives a superposition of signatures on those messages. Similarly, for encryption, we allow the adversary to issue quantum chosen ciphertext queries: given a superposition of ciphertexts, the adversary receives a superposition of their decryptions. These adversaries model a natural ubiquitous quantum computing environment where end-users sign messages and decrypt ciphertexts on a personal quantum computer. We construct classical systems that remain secure when exposed to such quantum queries. For signatures, we construct two compilers that convert classically secure signatures into signatures secure in the quantum setting and apply these compilers to existing post-quantum signatures. We also show that standard constructions such as Lamport one-time signatures and Merkle signatures remain secure under quantum chosen message attacks, thus giving signatures whose quantum security is based on generic assumptions. For encryption, we define security under quantum chosen ciphertext attacks and present both public-key and symmetric-key constructions. Keywords: Quantum computing, signatures, encryption, quantum security 1 Introduction Recent progress in building quantum computers [IBM12] gives hope for their eventual feasibility. Consequently, there is a growing need for quantum-secure cryptosystems, namely classical systems that remain secure against quantum computers. Post-quantum cryptography generally studies the settings where the adversary is armed with a quantum computer, but users only have classical machines. -
Comparative Analysis of Hash Authentication Algorithms and ECC Based Security Algorithms in Cloud Data
Asian Journal of Computer Science and Technology ISSN: 2249-0701 Vol.8 No.1, 2019, pp. 53-61 © The Research Publication, www.trp.org.in Comparative Analysis of Hash Authentication Algorithms and ECC Based Security Algorithms in Cloud Data S. Hendry Leo Kanickam1 and L. Jayasimman2 1Research Scholar, Department of Computer Science, 2Assistant Professor, Department of Computer Applications 1&2Bishop Heber College, Trichy, Tamil Nadu, India E-Mail: [email protected] Abstract - Cloud computing is ensuring the security of stored encryption techniques is not sufficient for information data in cloud computing servers is one of the mainly security over internet, therefore the combination of demanding issues. In Cloud numerous security issues arises encryption and encoding is broadly being used to attain such as authentication, integrity and confidentiality. Different integrity and confidentiality. There is need of a system that encryption techniques attempt to overcome these data security fulfills encrypted data transfer, verification and issues to an enormous extent. Hashing algorithm plays an important role in data integrity, message authentication, and authentication, therefore maintaining data confidentiality, to digital signature in modern information security. For security obtain rid of the same and to induce trust in the computing. purpose using encryption algorithm like ECC (Elliptic Curve The most important use of hybrid cryptographic algorithm Cryptography) and Authentication of data integrity using merges with digital signature and encryption algorithm to hashing algorithms like MD5, and SHA-512. This combination secure data stored in cloud. Subsequently, the encryption method provides data security, authentication and verification algorithm is used for data confidentiality and digital for secure cloud computing.