Cryptographic Extraction and Key Derivation: the HKDF Scheme
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Reconsidering the Security Bound of AES-GCM-SIV
Background on AES-GCM-SIV Fixing the Security Bound Improving Key Derivation Final Remarks Reconsidering the Security Bound of AES-GCM-SIV Tetsu Iwata1 and Yannick Seurin2 1Nagoya University, Japan 2ANSSI, France March 7, 2018 — FSE 2018 T. Iwata and Y. Seurin Reconsidering AES-GCM-SIV’s Security FSE 2018 1 / 26 Background on AES-GCM-SIV Fixing the Security Bound Improving Key Derivation Final Remarks Summary of the contribution • we reconsider the security of the AEAD scheme AES-GCM-SIV designed by Gueron, Langley, and Lindell • we identify flaws in the designers’ security analysis and propose a new security proof • our findings leads to significantly reduced security claims, especially for long messages • we propose a simple modification to the scheme (key derivation function) improving security without efficiency loss T. Iwata and Y. Seurin Reconsidering AES-GCM-SIV’s Security FSE 2018 2 / 26 Background on AES-GCM-SIV Fixing the Security Bound Improving Key Derivation Final Remarks Summary of the contribution • we reconsider the security of the AEAD scheme AES-GCM-SIV designed by Gueron, Langley, and Lindell • we identify flaws in the designers’ security analysis and propose a new security proof • our findings leads to significantly reduced security claims, especially for long messages • we propose a simple modification to the scheme (key derivation function) improving security without efficiency loss T. Iwata and Y. Seurin Reconsidering AES-GCM-SIV’s Security FSE 2018 2 / 26 Background on AES-GCM-SIV Fixing the Security Bound Improving Key Derivation Final Remarks Summary of the contribution • we reconsider the security of the AEAD scheme AES-GCM-SIV designed by Gueron, Langley, and Lindell • we identify flaws in the designers’ security analysis and propose a new security proof • our findings leads to significantly reduced security claims, especially for long messages • we propose a simple modification to the scheme (key derivation function) improving security without efficiency loss T. -
Modern Password Security for System Designers What to Consider When Building a Password-Based Authentication System
Modern password security for system designers What to consider when building a password-based authentication system By Ian Maddox and Kyle Moschetto, Google Cloud Solutions Architects This whitepaper describes and models modern password guidance and recommendations for the designers and engineers who create secure online applications. A related whitepaper, Password security for users, offers guidance for end users. This whitepaper covers the wide range of options to consider when building a password-based authentication system. It also establishes a set of user-focused recommendations for password policies and storage, including the balance of password strength and usability. The technology world has been trying to improve on the password since the early days of computing. Shared-knowledge authentication is problematic because information can fall into the wrong hands or be forgotten. The problem is magnified by systems that don't support real-world secure use cases and by the frequent decision of users to take shortcuts. According to a 2019 Yubico/Ponemon study, 69 percent of respondents admit to sharing passwords with their colleagues to access accounts. More than half of respondents (51 percent) reuse an average of five passwords across their business and personal accounts. Furthermore, two-factor authentication is not widely used, even though it adds protection beyond a username and password. Of the respondents, 67 percent don’t use any form of two-factor authentication in their personal life, and 55 percent don’t use it at work. Password systems often allow, or even encourage, users to use insecure passwords. Systems that allow only single-factor credentials and that implement ineffective security policies add to the problem. -
A Password-Based Key Derivation Algorithm Using the KBRP Method
American Journal of Applied Sciences 5 (7): 777-782, 2008 ISSN 1546-9239 © 2008 Science Publications A Password-Based Key Derivation Algorithm Using the KBRP Method 1Shakir M. Hussain and 2Hussein Al-Bahadili 1Faculty of CSIT, Applied Science University, P.O. Box 22, Amman 11931, Jordan 2Faculty of Information Systems and Technology, Arab Academy for Banking and Financial Sciences, P.O. Box 13190, Amman 11942, Jordan Abstract: This study presents a new efficient password-based strong key derivation algorithm using the key based random permutation the KBRP method. The algorithm consists of five steps, the first three steps are similar to those formed the KBRP method. The last two steps are added to derive a key and to ensure that the derived key has all the characteristics of a strong key. In order to demonstrate the efficiency of the algorithm, a number of keys are derived using various passwords of different content and length. The features of the derived keys show a good agreement with all characteristics of strong keys. In addition, they are compared with features of keys generated using the WLAN strong key generator v2.2 by Warewolf Labs. Key words: Key derivation, key generation, strong key, random permutation, Key Based Random Permutation (KBRP), key authentication, password authentication, key exchange INTRODUCTION • The key size must be long enough so that it can not Key derivation is the process of generating one or be easily broken more keys for cryptography and authentication, where a • The key should have the highest possible entropy key is a sequence of characters that controls the process (close to unity) [1,2] of a cryptographic or authentication algorithm . -
Implementation and Performance Analysis of PBKDF2, Bcrypt, Scrypt Algorithms
Implementation and Performance Analysis of PBKDF2, Bcrypt, Scrypt Algorithms Levent Ertaul, Manpreet Kaur, Venkata Arun Kumar R Gudise CSU East Bay, Hayward, CA, USA. [email protected], [email protected], [email protected] Abstract- With the increase in mobile wireless or data lookup. Whereas, Cryptographic hash functions are technologies, security breaches are also increasing. It has used for building blocks for HMACs which provides become critical to safeguard our sensitive information message authentication. They ensure integrity of the data from the wrongdoers. So, having strong password is that is transmitted. Collision free hash function is the one pivotal. As almost every website needs you to login and which can never have same hashes of different output. If a create a password, it’s tempting to use same password and b are inputs such that H (a) =H (b), and a ≠ b. for numerous websites like banks, shopping and social User chosen passwords shall not be used directly as networking websites. This way we are making our cryptographic keys as they have low entropy and information easily accessible to hackers. Hence, we need randomness properties [2].Password is the secret value from a strong application for password security and which the cryptographic key can be generated. Figure 1 management. In this paper, we are going to compare the shows the statics of increasing cybercrime every year. Hence performance of 3 key derivation algorithms, namely, there is a need for strong key generation algorithms which PBKDF2 (Password Based Key Derivation Function), can generate the keys which are nearly impossible for the Bcrypt and Scrypt. -
Security Policy: Informacast Java Crypto Library
FIPS 140-2 Non-Proprietary Security Policy: InformaCast Java Crypto Library FIPS 140-2 Non-Proprietary Security Policy InformaCast Java Crypto Library Software Version 3.0 Document Version 1.2 June 26, 2017 Prepared For: Prepared By: Singlewire Software SafeLogic Inc. 1002 Deming Way 530 Lytton Ave, Suite 200 Madison, WI 53717 Palo Alto, CA 94301 www.singlewire.com www.safelogic.com Document Version 1.2 © Singlewire Software Page 1 of 35 FIPS 140-2 Non-Proprietary Security Policy: InformaCast Java Crypto Library Abstract This document provides a non-proprietary FIPS 140-2 Security Policy for InformaCast Java Crypto Library. Document Version 1.2 © Singlewire Software Page 2 of 35 FIPS 140-2 Non-Proprietary Security Policy: InformaCast Java Crypto Library Table of Contents 1 Introduction .................................................................................................................................................. 5 1.1 About FIPS 140 ............................................................................................................................................. 5 1.2 About this Document.................................................................................................................................... 5 1.3 External Resources ....................................................................................................................................... 5 1.4 Notices ......................................................................................................................................................... -
Key Derivation Functions and Their GPU Implementation
MASARYK UNIVERSITY FACULTY}w¡¢£¤¥¦§¨ OF I !"#$%&'()+,-./012345<yA|NFORMATICS Key derivation functions and their GPU implementation BACHELOR’S THESIS Ondrej Mosnáˇcek Brno, Spring 2015 This work is licensed under a Creative Commons Attribution- NonCommercial-ShareAlike 4.0 International License. https://creativecommons.org/licenses/by-nc-sa/4.0/ cbna ii Declaration Hereby I declare, that this paper is my original authorial work, which I have worked out by my own. All sources, references and literature used or excerpted during elaboration of this work are properly cited and listed in complete reference to the due source. Ondrej Mosnáˇcek Advisor: Ing. Milan Brož iii Acknowledgement I would like to thank my supervisor for his guidance and support, and also for his extensive contributions to the Cryptsetup open- source project. Next, I would like to thank my family for their support and pa- tience and also to my friends who were falling behind schedule just like me and thus helped me not to panic. Last but not least, access to computing and storage facilities owned by parties and projects contributing to the National Grid In- frastructure MetaCentrum, provided under the programme “Projects of Large Infrastructure for Research, Development, and Innovations” (LM2010005), is also greatly appreciated. v Abstract Key derivation functions are a key element of many cryptographic applications. Password-based key derivation functions are designed specifically to derive cryptographic keys from low-entropy sources (such as passwords or passphrases) and to counter brute-force and dictionary attacks. However, the most widely adopted standard for password-based key derivation, PBKDF2, as implemented in most applications, is highly susceptible to attacks using Graphics Process- ing Units (GPUs). -
Hash Functions
11 Hash Functions Suppose you share a huge le with a friend, but you are not sure whether you both have the same version of the le. You could send your version of the le to your friend and they could compare to their version. Is there any way to check that involves less communication than this? Let’s call your version of the le x (a string) and your friend’s version y. The goal is to determine whether x = y. A natural approach is to agree on some deterministic function H, compute H¹xº, and send it to your friend. Your friend can compute H¹yº and, since H is deterministic, compare the result to your H¹xº. In order for this method to be fool-proof, we need H to have the property that dierent inputs always map to dierent outputs — in other words, H must be injective (1-to-1). Unfortunately, if H is injective and H : f0; 1gin ! f0; 1gout is injective, then out > in. This means that sending H¹xº is no better/shorter than sending x itself! Let us call a pair ¹x;yº a collision in H if x , y and H¹xº = H¹yº. An injective function has no collisions. One common theme in cryptography is that you don’t always need something to be impossible; it’s often enough for that thing to be just highly unlikely. Instead of saying that H should have no collisions, what if we just say that collisions should be hard (for polynomial-time algorithms) to nd? An H with this property will probably be good enough for anything we care about. -
The Double Ratchet Algorithm
The Double Ratchet Algorithm Trevor Perrin (editor) Moxie Marlinspike Revision 1, 2016-11-20 Contents 1. Introduction 3 2. Overview 3 2.1. KDF chains . 3 2.2. Symmetric-key ratchet . 5 2.3. Diffie-Hellman ratchet . 6 2.4. Double Ratchet . 13 2.6. Out-of-order messages . 17 3. Double Ratchet 18 3.1. External functions . 18 3.2. State variables . 19 3.3. Initialization . 19 3.4. Encrypting messages . 20 3.5. Decrypting messages . 20 4. Double Ratchet with header encryption 22 4.1. Overview . 22 4.2. External functions . 26 4.3. State variables . 26 4.4. Initialization . 26 4.5. Encrypting messages . 27 4.6. Decrypting messages . 28 5. Implementation considerations 29 5.1. Integration with X3DH . 29 5.2. Recommended cryptographic algorithms . 30 6. Security considerations 31 6.1. Secure deletion . 31 6.2. Recovery from compromise . 31 6.3. Cryptanalysis and ratchet public keys . 31 1 6.4. Deletion of skipped message keys . 32 6.5. Deferring new ratchet key generation . 32 6.6. Truncating authentication tags . 32 6.7. Implementation fingerprinting . 32 7. IPR 33 8. Acknowledgements 33 9. References 33 2 1. Introduction The Double Ratchet algorithm is used by two parties to exchange encrypted messages based on a shared secret key. Typically the parties will use some key agreement protocol (such as X3DH [1]) to agree on the shared secret key. Following this, the parties will use the Double Ratchet to send and receive encrypted messages. The parties derive new keys for every Double Ratchet message so that earlier keys cannot be calculated from later ones. -
Salting Vs Stretching Passwords for Enterprise Security
Salting vs Stretching Passwords for Enterprise Security Password security is important. Salting and stretching a password are two ways to make passwords more secure from attackers. You can use the strategies separately or deploy them in tandem for the most security. This article covers the logic of password protection, including salting and stretching passwords. Database attacks Because passwords are a user’s key to their data, they are a key target for attackers. Popular methods of password attacks happen through brute force and rainbow attacks: Brute force attacks are a trial and error approach where a computer guesses until it gets it right. This may sound ineffective, but computers can try many, many times. In this era of computing, “Hashcat breaks an 8 character full coverage (a-zA-Z0-9!-=) password in 26 days on a single 1080 Nvidia GPU.” Rainbow attacks are another form of cracking passwords, where all possible combinations of hashed passwords are pre-computed and stored in a dictionary. Then, an attacker runs through their list of hashes to find a match. If their scan returns a match, then they have the password. Passwords help prevent attacks First things first: nothing online is perfectly secure. Not even computers not connected to the internet are perfectly secure. We use passwords to minimize risk of attack, not to guarantee it will never happen. Though you cannot guarantee security, there are some ways to increase database security. Salting and stretching passwords are two such strategies: 1. Salting passwords. Designing the password encryption so only one password is compromised rather than the whole database. -
TMF: Asymmetric Cryptography Security Layer V1.0
GlobalPlatform Device Technology TMF: Asymmetric Cryptography Security Layer Version 1.0 Public Release March 2017 Document Reference: GPD_SPE_122 Copyright 2013-2017 GlobalPlatform, Inc. All Rights Reserved. Recipients of this document are invited to submit, with their comments, notification of any relevant patents or other intellectual property rights (collectively, “IPR”) of which they may be aware which might be necessarily infringed by the implementation of the specification or other work product set forth in this document, and to provide supporting documentation. The technology provided or described herein is subject to updates, revisions, and extensions by GlobalPlatform. Use of this information is governed by the GlobalPlatform license agreement and any use inconsistent with that agreement is strictly prohibited. TMF: Asymmetric Cryptography Security Layer – Public Release v1.0 THIS SPECIFICATION OR OTHER WORK PRODUCT IS BEING OFFERED WITHOUT ANY WARRANTY WHATSOEVER, AND IN PARTICULAR, ANY WARRANTY OF NON-INFRINGEMENT IS EXPRESSLY DISCLAIMED. ANY IMPLEMENTATION OF THIS SPECIFICATION OR OTHER WORK PRODUCT SHALL BE MADE ENTIRELY AT THE IMPLEMENTER’S OWN RISK, AND NEITHER THE COMPANY, NOR ANY OF ITS MEMBERS OR SUBMITTERS, SHALL HAVE ANY LIABILITY WHATSOEVER TO ANY IMPLEMENTER OR THIRD PARTY FOR ANY DAMAGES OF ANY NATURE WHATSOEVER DIRECTLY OR INDIRECTLY ARISING FROM THE IMPLEMENTATION OF THIS SPECIFICATION OR OTHER WORK PRODUCT. Copyright 2013-2017 GlobalPlatform, Inc. All Rights Reserved. The technology provided or described herein is subject to updates, revisions, and extensions by GlobalPlatform. Use of this information is governed by the GlobalPlatform license agreement and any use inconsistent with that agreement is strictly prohibited. TMF: Asymmetric Cryptography Security Layer – Public Release v1.0 3 / 38 Contents 1 Introduction ........................................................................................................................... -
Modes of Operation for Compressed Sensing Based Encryption
Modes of Operation for Compressed Sensing based Encryption DISSERTATION zur Erlangung des Grades eines Doktors der Naturwissenschaften Dr. rer. nat. vorgelegt von Robin Fay, M. Sc. eingereicht bei der Naturwissenschaftlich-Technischen Fakultät der Universität Siegen Siegen 2017 1. Gutachter: Prof. Dr. rer. nat. Christoph Ruland 2. Gutachter: Prof. Dr.-Ing. Robert Fischer Tag der mündlichen Prüfung: 14.06.2017 To Verena ... s7+OZThMeDz6/wjq29ACJxERLMATbFdP2jZ7I6tpyLJDYa/yjCz6OYmBOK548fer 76 zoelzF8dNf /0k8H1KgTuMdPQg4ukQNmadG8vSnHGOVpXNEPWX7sBOTpn3CJzei d3hbFD/cOgYP4N5wFs8auDaUaycgRicPAWGowa18aYbTkbjNfswk4zPvRIF++EGH UbdBMdOWWQp4Gf44ZbMiMTlzzm6xLa5gRQ65eSUgnOoZLyt3qEY+DIZW5+N s B C A j GBttjsJtaS6XheB7mIOphMZUTj5lJM0CDMNVJiL39bq/TQLocvV/4inFUNhfa8ZM 7kazoz5tqjxCZocBi153PSsFae0BksynaA9ZIvPZM9N4++oAkBiFeZxRRdGLUQ6H e5A6HFyxsMELs8WN65SCDpQNd2FwdkzuiTZ4RkDCiJ1Dl9vXICuZVx05StDmYrgx S6mWzcg1aAsEm2k+Skhayux4a+qtl9sDJ5JcDLECo8acz+RL7/ ovnzuExZ3trm+O 6GN9c7mJBgCfEDkeror5Af4VHUtZbD4vALyqWCr42u4yxVjSj5fWIC9k4aJy6XzQ cRKGnsNrV0ZcGokFRO+IAcuWBIp4o3m3Amst8MyayKU+b94VgnrJAo02Fp0873wa hyJlqVF9fYyRX+couaIvi5dW/e15YX/xPd9hdTYd7S5mCmpoLo7cqYHCVuKWyOGw ZLu1ziPXKIYNEegeAP8iyeaJLnPInI1+z4447IsovnbgZxM3ktWO6k07IOH7zTy9 w+0UzbXdD/qdJI1rENyriAO986J4bUib+9sY/2/kLlL7nPy5Kxg3 Et0Fi3I9/+c/ IYOwNYaCotW+hPtHlw46dcDO1Jz0rMQMf1XCdn0kDQ61nHe5MGTz2uNtR3bty+7U CLgNPkv17hFPu/lX3YtlKvw04p6AZJTyktsSPjubqrE9PG00L5np1V3B/x+CCe2p niojR2m01TK17/oT1p0enFvDV8C351BRnjC86Z2OlbadnB9DnQSP3XH4JdQfbtN8 BXhOglfobjt5T9SHVZpBbzhDzeXAF1dmoZQ8JhdZ03EEDHjzYsXD1KUA6Xey03wU uwnrpTPzD99cdQM7vwCBdJnIPYaD2fT9NwAHICXdlp0pVy5NH20biAADH6GQr4Vc -
CSE 291-I: Applied Cryptography
CSE 291-I: Applied Cryptography Nadia Heninger UCSD Fall 2020 Lecture 7 Legal Notice The Zoom session for this class will be recorded and made available asynchronously on Canvas to registered students. Announcements 1. HW 3 is due next Tuesday. 2. HW 4 is online, due before class in 1.5 weeks, November 3. Last time: Hash functions This time: Hash-based MACs, authenticated encryption Constructing a MAC from a hash function Recall: Collision-resistant hash function: Unkeyed function • H : 0, 1 0, 1 n hard to find inputs mapping to same { }⇤ !{ } output. MAC: Keyed function Mac (m)=t,hardforadversaryto • k construct valid (m, t) pair. functor alone not- MAC : anyone can (m Hcm)) Hash forge , No secrets . Insecure. Vulnerable to length extension attacks for Merkle-Damgård functions. Secure for SHA3 sponge. Ok, but vulnerable to offline collision-finding attacks against H. Ok, but nobody uses. Secure, similar to HMAC. Candidate MAC constructions Mac(k, m)=H(k m) • || Mac(k, m)=H(m k) • || Mac(k, m)=H(k m k) • || || Mac(k , k , m)=H(k H(k m)) • 1 2 2|| 1|| Ok, but vulnerable to offline collision-finding attacks against H. Ok, but nobody uses. Secure, similar to HMAC. Candidate MAC constructions Mac(k, m)=H(k m) • || Insecure. Vulnerable to length extension attacks for Merkle-Damgård functions. Secure for SHA3 sponge. Mac(k, m)=H(m k) • || Mac(k, m)=H(k m k) • || || Mac(k , k , m)=H(k H(k m)) • 1 2 2|| 1|| Ok, but nobody uses. Secure, similar to HMAC.