XEP-0438: Best Practices for Password Hashing and Storage
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Argon and Argon2
Argon and Argon2 Designers: Alex Biryukov, Daniel Dinu, and Dmitry Khovratovich University of Luxembourg, Luxembourg [email protected], [email protected], [email protected] https://www.cryptolux.org/index.php/Password https://github.com/khovratovich/Argon https://github.com/khovratovich/Argon2 Version 1.1 of Argon Version 1.0 of Argon2 31th January, 2015 Contents 1 Introduction 3 2 Argon 5 2.1 Specification . 5 2.1.1 Input . 5 2.1.2 SubGroups . 6 2.1.3 ShuffleSlices . 7 2.2 Recommended parameters . 8 2.3 Security claims . 8 2.4 Features . 9 2.4.1 Main features . 9 2.4.2 Server relief . 10 2.4.3 Client-independent update . 10 2.4.4 Possible future extensions . 10 2.5 Security analysis . 10 2.5.1 Avalanche properties . 10 2.5.2 Invariants . 11 2.5.3 Collision and preimage attacks . 11 2.5.4 Tradeoff attacks . 11 2.6 Design rationale . 14 2.6.1 SubGroups . 14 2.6.2 ShuffleSlices . 16 2.6.3 Permutation ...................................... 16 2.6.4 No weakness,F no patents . 16 2.7 Tweaks . 17 2.8 Efficiency analysis . 17 2.8.1 Modern x86/x64 architecture . 17 2.8.2 Older CPU . 17 2.8.3 Other architectures . 17 3 Argon2 19 3.1 Specification . 19 3.1.1 Inputs . 19 3.1.2 Operation . 20 3.1.3 Indexing . 20 3.1.4 Compression function G ................................. 21 3.2 Features . 22 3.2.1 Available features . 22 3.2.2 Server relief . 23 3.2.3 Client-independent update . -
CASH: a Cost Asymmetric Secure Hash Algorithm for Optimal Password Protection
CASH: A Cost Asymmetric Secure Hash Algorithm for Optimal Password Protection Jeremiah Blocki Anupam Datta Microsoft Research Carnegie Mellon University August 23, 2018 Abstract An adversary who has obtained the cryptographic hash of a user's password can mount an offline attack to crack the password by comparing this hash value with the cryptographic hashes of likely password guesses. This offline attacker is limited only by the resources he is willing to invest to crack the password. Key-stretching techniques like hash iteration and memory hard functions have been proposed to mitigate the threat of offline attacks by making each password guess more expensive for the adversary to verify. However, these techniques also increase costs for a legitimate authentication server. We introduce a novel Stackelberg game model which captures the essential elements of this interaction between a defender and an offline attacker. In the game the defender first commits to a key-stretching mechanism, and the offline attacker responds in a manner that optimizes his utility (expected reward minus expected guessing costs). We then introduce Cost Asymmetric Secure Hash (CASH), a randomized key-stretching mechanism that minimizes the fraction of passwords that would be cracked by a rational offline attacker without increasing amortized authentication costs for the legitimate authentication server. CASH is motivated by the observation that the legitimate authentication server will typically run the authentication procedure to verify a correct password, while an offline adversary will typically use incorrect password guesses. By using randomization we can ensure that the amortized cost of running CASH to verify a correct password guess is significantly smaller than the cost of rejecting an incorrect password. -
Extensible Authentication Protocol (EAP) and IEEE 802.1X: Tutorial and Empirical Experience
CHEN LAYOUT 11/17/05 11:57 AM Page 52 Extensible Authentication Protocol (EAP) and IEEE 802.1x: Tutorial and Empirical Experience JYH-CHENG CHEN AND YU-PING WANG, NATIONAL TSING HUA UNIVERSITY Abstract oped WIRE1x to support various versions of MS Windows. As This article presents the technical details of the Extensible the name suggests, WIRE1x is an open-source implementa- Authentication Protocol (EAP) and IEEE 802.1x by using tion of IEEE 802.1x client (supplicant)1 developed by the WIRE1x, an open-source implementation of IEEE 802.1x Wireless Internet Research & Engineering (WIRE) Laborato- client (supplicant) and various EAP-based authentication ry.2 Both source code and executable code of WIRE1x can be mechanisms. By using a real implementation, 802.1x and EAP downloaded freely from http://wire.cs.nthu.edu.tw/wire1x/. should be easily understood. Essentially, 802.1x provides a framework for port-based access control. It can work with various authentication mecha- nisms to authenticate and authorize users. The Extensible Introduction Authentication Protocol (EAP, IETF RFC 2284) is a protocol Wireless local area networks (WLANs) have become increas- commonly used in 802.1x to authenticate users. Currently, ingly more prevalent in recent years. The IEEE 802.11 stan- WIRE1x provides various authentication mechanisms, includ- dard is one of the most widely adopted standards for ing EAP Message Digest 5 (EAP-MD5, IETF RFC 1321), broadband wireless Internet access. However, security consid- EAP Transport Layer Security (EAP-TLS, IETF RFC 2716), erations with regard to wireless environments are more com- EAP Tunneled TLS (EAP-TTLS) [5], and Protected Extensi- plicated than those in wired environments. -
Kerberos: an Authentication Service for Computer Networks by Clifford Neuman and Theodore Ts’O
Kerberos: An Authentication Service for Computer Networks by Clifford Neuman and Theodore Ts’o Presented by: Smitha Sundareswaran Chi Tsong Su Introduction z Kerberos: An authentication protocol based on cryptography z Designed at MIT under project Athena z Variation of Needham Schroeder protocol - Difference: Kerberos assumes all systems on the network to be synchronized z Similar function as its mythological namesake: “guards” the access to network protocols Contribution z Defines ideas of authentication, Integrity, confidentiality and Authorization z Working of Kerberos z Limitations z Utilities z How to obtain and use Kerberos z Other methods to improve security Why Kerberos? z Foils threats due to eavesdropping z More convenient than password based authentication { Allows user to avoid “authentication by assertion” z Authentication based on cryptography: attacker can’t impersonate a valid user How Kerberos Works z Distributed authentication service using a series of encrypted messages {Password doesn’t pass through the network z Timestamps to reduce the number of messages needed for authentication z “Ticket granting Service” for subsequent authentication Kerberos Authentication and Encryption zAuthentication proves that a client is running on behalf of a particular user zUses encryption key for authentication {Encryption key = Password zEncryption implemented using DES {Checksum included in message checksum and encryption provide integrity & confidentiality The Kerberos Ticket z Initially, client and Server don’t share an encryption -
Rifflescrambler – a Memory-Hard Password Storing Function ⋆
RiffleScrambler – a memory-hard password storing function ? Karol Gotfryd1, Paweł Lorek2, and Filip Zagórski1;3 1 Wrocław University of Science and Technology Faculty of Fundamental Problems of Technology Department of Computer Science 2 Wrocław University Faculty of Mathematics and Computer Science Mathematical Institute 3 Oktawave Abstract. We introduce RiffleScrambler: a new family of directed acyclic graphs and a corresponding data-independent memory hard function with password independent memory access. We prove its memory hard- ness in the random oracle model. RiffleScrambler is similar to Catena – updates of hashes are determined by a graph (bit-reversal or double-butterfly graph in Catena). The ad- vantage of the RiffleScrambler over Catena is that the underlying graphs are not predefined but are generated per salt, as in Balloon Hashing. Such an approach leads to higher immunity against practical parallel at- tacks. RiffleScrambler offers better efficiency than Balloon Hashing since the in-degree of the underlying graph is equal to 3 (and is much smaller than in Ballon Hashing). At the same time, because the underlying graph is an instance of a Superconcentrator, our construction achieves the same time-memory trade-offs. Keywords: Memory hardness, password storing, Markov chains, mixing time. 1 Introduction In early days of computers’ era passwords were stored in plaintext in the form of pairs (user; password). Back in 1960s it was observed, that it is not secure. It took around a decade to incorporate a more secure way of storing users’ passwords – via a DES-based function crypt, as (user; fk(password)) for a se- cret key k or as (user; f(password)) for a one-way function. -
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. -
Cs 255 (Introduction to Cryptography)
CS 255 (INTRODUCTION TO CRYPTOGRAPHY) DAVID WU Abstract. Notes taken in Professor Boneh’s Introduction to Cryptography course (CS 255) in Winter, 2012. There may be errors! Be warned! Contents 1. 1/11: Introduction and Stream Ciphers 2 1.1. Introduction 2 1.2. History of Cryptography 3 1.3. Stream Ciphers 4 1.4. Pseudorandom Generators (PRGs) 5 1.5. Attacks on Stream Ciphers and OTP 6 1.6. Stream Ciphers in Practice 6 2. 1/18: PRGs and Semantic Security 7 2.1. Secure PRGs 7 2.2. Semantic Security 8 2.3. Generating Random Bits in Practice 9 2.4. Block Ciphers 9 3. 1/23: Block Ciphers 9 3.1. Pseudorandom Functions (PRF) 9 3.2. Data Encryption Standard (DES) 10 3.3. Advanced Encryption Standard (AES) 12 3.4. Exhaustive Search Attacks 12 3.5. More Attacks on Block Ciphers 13 3.6. Block Cipher Modes of Operation 13 4. 1/25: Message Integrity 15 4.1. Message Integrity 15 5. 1/27: Proofs in Cryptography 17 5.1. Time/Space Tradeoff 17 5.2. Proofs in Cryptography 17 6. 1/30: MAC Functions 18 6.1. Message Integrity 18 6.2. MAC Padding 18 6.3. Parallel MAC (PMAC) 19 6.4. One-time MAC 20 6.5. Collision Resistance 21 7. 2/1: Collision Resistance 21 7.1. Collision Resistant Hash Functions 21 7.2. Construction of Collision Resistant Hash Functions 22 7.3. Provably Secure Compression Functions 23 8. 2/6: HMAC And Timing Attacks 23 8.1. HMAC 23 8.2. -
PUF Based Authentication Protocol for Iot
S S symmetry Article PUF Based Authentication Protocol for IoT An Braeken Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel, Belgium; [email protected]; Tel.: +32-468-104-767 Received: 11 July 2018; Accepted: 11 August 2018; Published: 20 August 2018 Abstract: Key agreement between two constrained Internet of Things (IoT) devices that have not met each other is an essential feature to provide in order to establish trust among its users. Physical Unclonable Functions (PUFs) on a device represent a low cost primitive exploiting the unique random patterns in the device and have been already applied in a multitude of applications for secure key generation and key agreement in order to avoid an attacker to take over the identity of a tampered device, whose key material has been extracted. This paper shows that the key agreement scheme of a recently proposed PUF based protocol, presented by Chatterjee et al., for Internet of Things (IoT) is vulnerable for man-in-the-middle, impersonation, and replay attacks in the Yao–Dolev security model. We propose an alternative scheme, which is able to solve these issues and can provide in addition a more efficient key agreement and subsequently a communication phase between two IoT devices connected to the same authentication server. The scheme also offers identity based authentication and repudiation, when only using elliptic curve multiplications and additions, instead of the compute intensive pairing operations. Keywords: physical unclonable function; authentication; elliptic curve cryptography; internet of things 1. Introduction Internet of Things (IoT) is experiencing worldwide growth. Not only classical computing and communication devices are connected, but also a whole range of other gadgets that are used in our daily life, such as thermostats, light switches, door locks, refrigerators, etc. -
Recommendation for EAP Methods
Archived NIST Technical Series Publication The attached publication has been archived (withdrawn), and is provided solely for historical purposes. It may have been superseded by another publication (indicated below). Archived Publication Series/Number: NIST Special Publication 800-120 Title: Recommendation for EAP Methods Used in Wireless Network Access Authentication Publication Date(s): September 2009 Withdrawal Date: October 19, 2018 Withdrawal Note: This publication is out of date. Refer to relevant standards from the Internet Engineering Task Force (IETF), http://www.ietf.org/ . Superseding Publication(s) The attached publication has been superseded by the following publication(s): Series/Number: Title: Author(s): Publication Date(s): URL/DOI: Additional Information (if applicable) Contact: Computer Security Division (Information Technology Laboratory) Latest revision of the attached publication: Related information: https://csrc.nist.gov https://csrc.nist.gov/publications/detail/sp/800-120/archive/2009-09-17 Withdrawal N/A announcement (link): Date updated: October 19, 2018 NIST Special Publication 800-120 Recommendation for EAP Methods Used in Wireless Network Access Authentication Katrin Hoeper and Lily Chen Computer Security Division Information Technology Laboratory C O M P U T E R S E C U R I T Y September 2009 U.S. Department of Commerce Gary Locke, Secretary National Institute of Standards and Technology Patrick Gallagher, Deputy Director Abstract This Recommendation specifies security requirements for authentication methods with key establishment supported by the Extensible Authentication Protocol (EAP) defined in IETF RFC 3748 for wireless access authentications to federal networks. KEY WORDS: EAP methods, authentication, key establishment. SP 800-120: Recommendation for EAP Methods Used in Wireless Network Access Authentication Acknowledgments The authors, Katrin Hoeper and Lily Chen, wish to thank their colleagues who reviewed drafts of this document and contributed to its technical content. -
Diameter-Based Protocol in the IP Multimedia Subsystem
International Journal of Soft Computing and Engineering (IJSCE) ISSN: 2231 – 2307, Volume- 1 Issue- 6, January 2012 Diameter-Based Protocol in the IP Multimedia Subsystem Vinay Kumar.S.B, Manjula N Harihar Abstract— The Diameter protocol was initially developed by II. ROLE OF DIAMETER IN IMS the Internet Engineering Task Force (IETF) as an Authentication, Authorization, and Accounting (AAA) framework The IMS is based on a horizontally layered architecture, intended for applications such as remote network access and IP consisting of three layers, namely, Service Layer, Control mobility. Diameter was further embraced by the Third Generation Layer, and Connectivity Layer. Service Layer comprises Partnership Project (3GPP) as the key protocol for AAA and application and content servers to execute value-added mobility management in 3G networks. The paper discusses the use services for the user. Control layer comprises network control of Diameter in the scope of the IP Multimedia Subsystem (IMS) as servers for managing call or session set-up, modification and specified by 3GPP. This paper presents a solution for the problem release. The most important of these is the Call Session of how to provide authentication, authorization and accounting Control Function (CSCF). Connectivity Layer comprises of (AAA) for multi-domain interacting services by referring open routers and switches, for both the backbone and the access diameter. We have studied the case of ‘FoneFreez’, a service that provides interaction between different basic services, like network telephony and television. The involvement of several parties like A. IMS functions television provider, telephony provider etc., secure interaction between multiple domains must be assured. -
Formal Analysis of Combinations of Secure Protocols Elliott Blot, Jannik Dreier, Pascal Lafourcade
Formal Analysis of Combinations of Secure Protocols Elliott Blot, Jannik Dreier, Pascal Lafourcade To cite this version: Elliott Blot, Jannik Dreier, Pascal Lafourcade. Formal Analysis of Combinations of Secure Protocols. FPS 2017 - 10th International Symposium on Foundations & Practice of Security, Oct 2017, Nancy, France. pp.53-67, 10.1007/978-3-319-75650-9_4. hal-01596010v2 HAL Id: hal-01596010 https://hal.archives-ouvertes.fr/hal-01596010v2 Submitted on 11 Nov 2017 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. Formal Analysis of Combinations of Secure Protocols? Elliott Blot1, Jannik Dreier2, and Pascal Lafourcade1 1 LIMOS, University Clermont Auvergne, France [email protected] 2 LORIA, Universit´ede Lorraine, INRIA, CNRS, France [email protected] 3 LIMOS, University Clermont Auvergne, France [email protected] Abstract. When trying to prove the security of a protocol, one usually analyzes the protocol in isolation, i.e., in a network with no other proto- cols. But in reality, there will be many protocols operating on the same network, maybe even sharing data including keys, and an intruder may use messages of one protocol to break another. We call that a multi- protocol attack. -
Salted Challenge Response Authentication Mechanism (SCRAM) SASL Authentication Mechanism
Salted Challenge Response Authentication Mechanism (SCRAM) SASL authentication mechanism draft-newman-auth-scram-10.txt draft-newman-auth-scram-gs2-01.txt Abhijit Menon-Sen <[email protected]> Chris Newman <[email protected]> Alexey Melnikov <[email protected]> Simon Josefsson <[email protected]> IETF 74, Sa n Francisco SASL Framework • Specified in RFC 4422 • Used by application layer protocols – IMAP – RFC 3501 – POP3 – RFC 5034 – LDAP – RFC 4510 – SMTP – RFC 4954 – ManageSieve – RFC-ietf-sieve-managesieve-09.txt – XMPP – RFC 3920 – BEEP – RFC 3080 – And few others • Not used by HTTP Existing password based SASL mechanisms (1 of 3) • PLAIN – Doesn't support server authentication – And sends username/password in the cleartext, so it relies on encryption provided by lower- level security services (e.g., TLS) – Can be used with most authentication databases – Allows “bad” servers to reuse the password in order to break into other user's accounts Existing password based SASL mechanisms (2 of 3) • CRAM-MD5 – Doesn't send password in cleartext – But doesn't support server authentication – Doesn't support some modern SASL features like • Internationalization • Acting on behalf of other users • Channel bindings – So it is simple to implement, but not considered secure anymore (e.g. it allows connection hijacking) Existing password based SASL mechanisms (3 of 3) • DIGEST-MD5 – Doesn't send password in cleartext – Supports server authentication – Was designed to be compatible with HTTP-Digest but in practice this compatibility is limited