Chapter 4 Cryptographic Hash Functions Hash Function
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Increasing Cryptography Security Using Hash-Based Message
ISSN (Print) : 2319-8613 ISSN (Online) : 0975-4024 Seyyed Mehdi Mousavi et al. / International Journal of Engineering and Technology (IJET) Increasing Cryptography Security using Hash-based Message Authentication Code Seyyed Mehdi Mousavi*1, Dr.Mohammad Hossein Shakour 2 1-Department of Computer Engineering, Shiraz Branch, Islamic AzadUniversity, Shiraz, Iran . Email : [email protected] 2-Assistant Professor, Department of Computer Engineering, Shiraz Branch, Islamic Azad University ,Shiraz ,Iran Abstract Nowadays, with the fast growth of information and communication technologies (ICTs) and the vulnerabilities threatening human societies, protecting and maintaining information is critical, and much attention should be paid to it. In the cryptography using hash-based message authentication code (HMAC), one can ensure the authenticity of a message. Using a cryptography key and a hash function, HMAC creates the message authentication code and adds it to the end of the message supposed to be sent to the recipient. If the recipient of the message code is the same as message authentication code, the packet will be confirmed. The study introduced a complementary function called X-HMAC by examining HMAC structure. This function uses two cryptography keys derived from the dedicated cryptography key of each packet and the dedicated cryptography key of each packet derived from the main X-HMAC cryptography key. In two phases, it hashes message bits and HMAC using bit Swapp and rotation to left. The results show that X-HMAC function can be a strong barrier against data identification and HMAC against the attacker, so that it cannot attack it easily by identifying the blocks and using HMAC weakness. -
The Order of Encryption and Authentication for Protecting Communications (Or: How Secure Is SSL?)?
The Order of Encryption and Authentication for Protecting Communications (Or: How Secure is SSL?)? Hugo Krawczyk?? Abstract. We study the question of how to generically compose sym- metric encryption and authentication when building \secure channels" for the protection of communications over insecure networks. We show that any secure channels protocol designed to work with any combina- tion of secure encryption (against chosen plaintext attacks) and secure MAC must use the encrypt-then-authenticate method. We demonstrate this by showing that the other common methods of composing encryp- tion and authentication, including the authenticate-then-encrypt method used in SSL, are not generically secure. We show an example of an en- cryption function that provides (Shannon's) perfect secrecy but when combined with any MAC function under the authenticate-then-encrypt method yields a totally insecure protocol (for example, ¯nding passwords or credit card numbers transmitted under the protection of such protocol becomes an easy task for an active attacker). The same applies to the encrypt-and-authenticate method used in SSH. On the positive side we show that the authenticate-then-encrypt method is secure if the encryption method in use is either CBC mode (with an underlying secure block cipher) or a stream cipher (that xor the data with a random or pseudorandom pad). Thus, while we show the generic security of SSL to be broken, the current practical implementations of the protocol that use the above modes of encryption are safe. 1 Introduction The most widespread application of cryptography in the Internet these days is for implementing a secure channel between two end points and then exchanging information over that channel. -
Hello, and Welcome to This Presentation of the STM32MP1 Hash Processor
Hello, and welcome to this presentation of the STM32MP1 hash processor. 1 Hash peripheral is in charge of efficient computing of message digest. A digest is a fixed-length value computed from an input message. A digest is unique - it is virtually impossible to find two messages with the same digest. The original message cannot be retrieved from its digest. Hash digests and Hash-based Message Authentication Code (HMAC) are widely used in communication since they are used to guarantee the integrity and authentication of a transfer. 2 HASH1 is a secure peripheral (under ETZPC control through ETZPC_DECPROT0 bit 8) while HASH2 is a non secure peripheral. HASH1 instance can be allocated to: • The Arm® Cortex®-A7 secure core to be controlled in OP-TEE by the HASH OP-TEE driver or • The Arm® Cortex® -A7 non-secure core for using in Linux® with Linux Crypto framework HASH2 instance can be allocated to the Arm® Cortex®-M4 core to be controlled in the STM32Cube MPU Package using the STM32Cube HASH driver. HASH1 instance is used as boot device to support binary authentication. 3 The hash processor supports widely used hash functions including Message Digest 5 (MD5), Secure Hash Algorithm SHA-1 and the more recent SHA-2 with its 224- and 256-bit digest length versions. A hash can also be generated with a secrete-key to produce a message authentication code (MAC). The processor supports bit, byte and half-word swapping. It supports also automatic padding of input data for block alignment. The processor can be used in conjunction with the DMA for automatic processor feeding. -
Authenticated Key-Exchange: Protocols, Attacks, and Analyses
The HMAC construction: A decade later Ran Canetti IBM Research What is HMAC? ● HMAC: A Message Authentication Code based on Cryptographic Hash functions [Bellare-C-Krawczyk96]. ● Developed for the IPSec standard of the Internet Engineering Task Force (IETF). ● Currently: - incorporated in IPSec, SSL/TLS, SSH, Kerberos, SHTTP, HTTPS, SRTP, MSEC, ... - ANSI and NIST standards - Used daily by all of us. Why is HMAC interesting? ● “Theoretical” security analysis impacts the security of real systems. ● Demonstrates the importance of modelling and abstraction in practical cryptography. ● The recent attacks on hash functions highlight the properties of the HMAC design and analysis. ● Use the HMAC lesson to propose requirements for the next cryptographic hash function. Organization ● Authentication, MACs, Hash-based MACs ● HMAC construction and analysis ● Other uses of HMAC: ● Pseudo-Random Functions ● Extractors ● What properties do we want from a “cryptographic hash function”? Authentication m m' A B The goal: Any tampering with messages should be detected. “If B accepts message m from A then A has sent m to B.” • One of the most basic cryptographic tasks • The basis for any security-conscious interaction over an open network Elements of authentication The structure of typical cryptographic solutions: • Initial entity authentication: The parties perform an initial exchange, bootstrapping from initial trusted information on each other. The result is a secret key that binds the parties to each other. • Message authentication: The parties use the key to authenticate exchanged messages via message authentication codes. Message Authentication Codes m,t m',t' A B t=FK(m) t' =? FK(m') • A and B obtain a common secret key K • A and B agree on a keyed function F • A sends t=FK(m) together with m • B gets (m',t') and accepts m' if t'=FK(m'). -
Downloaded on 2017-02-12T13:16:07Z HARDWARE DESIGNOF CRYPTOGRAPHIC ACCELERATORS
Title Hardware design of cryptographic accelerators Author(s) Baldwin, Brian John Publication date 2013 Original citation Baldwin, B.J., 2013. Hardware design of cryptographic accelerators. PhD Thesis, University College Cork. Type of publication Doctoral thesis Rights © 2013. Brian J. Baldwin http://creativecommons.org/licenses/by-nc-nd/3.0/ Embargo information No embargo required Item downloaded http://hdl.handle.net/10468/1112 from Downloaded on 2017-02-12T13:16:07Z HARDWARE DESIGN OF CRYPTOGRAPHIC ACCELERATORS by BRIAN BALDWIN Thesis submitted for the degree of PHD from the Department of Electrical Engineering National University of Ireland University College, Cork, Ireland May 7, 2013 Supervisor: Dr. William P. Marnane “What I cannot create, I do not understand” - Richard Feynman; on his blackboard at time of death in 1988. Contents 1 Introduction 1 1.1 Motivation...................................... 1 1.2 ThesisAims..................................... 3 1.3 ThesisOutline................................... 6 2 Background 9 2.1 Introduction.................................... 9 2.2 IntroductiontoCryptography. ...... 10 2.3 MathematicalBackground . ... 13 2.3.1 Groups ................................... 13 2.3.2 Rings .................................... 14 2.3.3 Fields.................................... 15 2.3.4 FiniteFields ................................ 16 2.4 EllipticCurves .................................. 17 2.4.1 TheGroupLaw............................... 18 2.4.2 EllipticCurvesoverPrimeFields . .... 19 2.5 CryptographicPrimitives&Protocols -
A Full Key Recovery Attack on HMAC-AURORA-512
A Full Key Recovery Attack on HMAC-AURORA-512 Yu Sasaki NTT Information Sharing Platform Laboratories, NTT Corporation 3-9-11 Midori-cho, Musashino-shi, Tokyo, 180-8585 Japan [email protected] Abstract. In this note, we present a full key recovery attack on HMAC- AURORA-512 when 512-bit secret keys are used and the MAC length is 512-bit long. Our attack requires 2257 queries and the off-line com- plexity is 2259 AURORA-512 operations, which is significantly less than the complexity of the exhaustive search for a 512-bit key. The attack can be carried out with a negligible amount of memory. Our attack can also recover the inner-key of HMAC-AURORA-384 with almost the same complexity as in HMAC-AURORA-512. This attack does not recover the outer-key of HMAC-AURORA-384, but universal forgery is possible by combining the inner-key recovery and 2nd-preimage attacks. Our attack exploits some weaknesses in the mode of operation. keywords: AURORA, DMMD, HMAC, Key recovery attack 1 Description 1.1 Mode of operation for AURORA-512 We briefly describe the specification of AURORA-512. Please refer to Ref. [2] for details. An input message is padded to be a multiple of 512 bits by the standard MD message padding, then, the padded message is divided into 512-bit message blocks (M0;M1;:::;MN¡1). 256 512 256 In AURORA-512, compression functions Fk : f0; 1g £f0; 1g ! f0; 1g 256 512 256 512 and Gk : f0; 1g £ f0; 1g ! f0; 1g , two functions MF : f0; 1g ! f0; 1g512 and MFF : f0; 1g512 ! f0; 1g512, and two initial 256-bit chaining U D 1 values H0 and H0 are defined . -
The First Collision for Full SHA-1
The first collision for full SHA-1 Marc Stevens1, Elie Bursztein2, Pierre Karpman1, Ange Albertini2, Yarik Markov2 1 CWI Amsterdam 2 Google Research [email protected] https://shattered.io Abstract. SHA-1 is a widely used 1995 NIST cryptographic hash function standard that was officially deprecated by NIST in 2011 due to fundamental security weaknesses demonstrated in various analyses and theoretical attacks. Despite its deprecation, SHA-1 remains widely used in 2017 for document and TLS certificate signatures, and also in many software such as the GIT versioning system for integrity and backup purposes. A key reason behind the reluctance of many industry players to replace SHA-1 with a safer alternative is the fact that finding an actual collision has seemed to be impractical for the past eleven years due to the high complexity and computational cost of the attack. In this paper, we demonstrate that SHA-1 collision attacks have finally become practical by providing the first known instance of a collision. Furthermore, the prefix of the colliding messages was carefully chosen so that they allow an attacker to forge two PDF documents with the same SHA-1 hash yet that display arbitrarily-chosen distinct visual contents. We were able to find this collision by combining many special cryptanalytic techniques in complex ways and improving upon previous work. In total the computational effort spent is equivalent to 263:1 SHA-1 compressions and took approximately 6 500 CPU years and 100 GPU years. As a result while the computational power spent on this collision is larger than other public cryptanalytic computations, it is still more than 100 000 times faster than a brute force search. -
Related-Key and Key-Collision Attacks Against RMAC
Related-Key and Key-Collision Attacks Against RMAC Tadayoshi Kohno CSE Department, UC San Diego 9500 Gilman Drive, MC-0114 La Jolla, California 92093-0114, USA IACR ePrint archive 2002/159, 21 October 2002, revised 2 December 2002. Abstract. In [JJV02] Jaulmes, Joux, and Valette propose a new ran- domized message authentication scheme, called RMAC, which NIST is currently in the process of standardizing [NIS02]. In this work we present several attacks against RMAC. The attacks are based on a new protocol- level related-key attack against RMAC and can be considered variants of Biham’s key-collision attack [Bih02]. These attacks provide insights into the RMAC design. We believe that the protocol-level related-key attack is of independent interest. Keywords: RMAC, key-collision attacks, related-key attacks. 1 Introduction Jaulmes, Joux, and Valette’s RMAC construction [JJV02] is a new ran- domized message authentication scheme. Similar to Petrank and Rackoff’s DMAC construction [PR97] and Black and Rogaway’s ECBC construc- tion [BR00], the RMAC construction is a CBC-MAC variant in which an input message is first MACed with standard CBC-MAC and then the resulting intermediate value is enciphered with one additional block ci- pher application. Rather than using a fixed key for the last block cipher application (as DMAC and ECBC do), RMAC enciphers the last block with a randomly chosen (but related) key. One immediate observation is that RMAC directly exposes the underlying block cipher to a weak form of related-key attacks [Bih93]. We are interested in attacks that do not exploit some related-key weakness of the underlying block cipher, but rather some property of the RMAC mode itself. -
A New Approach in Expanding the Hash Size of MD5
374 International Journal of Communication Networks and Information Security (IJCNIS) Vol. 10, No. 2, August 2018 A New Approach in Expanding the Hash Size of MD5 Esmael V. Maliberan, Ariel M. Sison, Ruji P. Medina Graduate Programs, Technological Institute of the Philippines, Quezon City, Philippines Abstract: The enhanced MD5 algorithm has been developed by variants and RIPEMD-160. These hash algorithms are used expanding its hash value up to 1280 bits from the original size of widely in cryptographic protocols and internet 128 bit using XOR and AND operators. Findings revealed that the communication in general. Among several hashing hash value of the modified algorithm was not cracked or hacked algorithms mentioned above, MD5 still surpasses the other during the experiment and testing using powerful bruteforce, since it is still widely used in the domain authentication dictionary, cracking tools and rainbow table such as security owing to its feature of irreversible [41]. This only CrackingStation, Hash Cracker, Cain and Abel and Rainbow Crack which are available online thus improved its security level means that the confirmation does not need to demand the compared to the original MD5. Furthermore, the proposed method original data but only need to have an effective digest to could output a hash value with 1280 bits with only 10.9 ms confirm the identity of the client. The MD5 message digest additional execution time from MD5. algorithm was developed by Ronald Rivest sometime in 1991 to change a previous hash function MD4, and it is commonly Keywords: MD5 algorithm, hashing, client-server used in securing data in various applications [27,23,22]. -
Hello, and Welcome to This Presentation of the STM32 Hash Processor
Hello, and welcome to this presentation of the STM32 hash processor. 1 Hash peripheral is in charge of efficient computing of message digest. A digest is a fixed-length value computed from an input message. A digest is unique - it is virtually impossible to find two messages with the same digest. The original message cannot be retrieved from its digest. Hash digests and Hash-based Message Authentication Code (HMAC) are widely used in communication since they are used to guarantee the integrity and authentication of a transfer. 2 The hash processor supports widely used hash functions including Message Digest 5 (MD5), Secure Hash Algorithm SHA-1 and the more recent SHA-2 with its 224- and 256- bit digest length versions. A hash can also be generated with a secrete-key to produce a message authentication code (MAC). The processor supports bit, byte and half-word swapping. It supports also automatic padding of input data for block alignment. The processor can be used in conjunction with the DMA for automatic processor feeding. 3 All supported hash functions work on 512-bit blocks of data. The input message is split as many times as needed to feed the hash processor. Subsequent blocks are computed sequentially. MD5 is the less robust function with only a 128-bit digest. The SHA standard has two versions SHA-1 and the more recent SHA-2 with its 224- and 256-bit digest length versions. 4 The hash-based message authentication code (HMAC) is used to authenticate messages and verify their integrity. The HMAC function consists of two nested Hash function with a secrete key that is shared by the sender and the receiver. -
Recommendation for Applications Using Approved Hash Algorithms
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 800-107 Title: Recommendation for Applications Using Approved Hash Algorithms Publication Date(s): February 2009 Withdrawal Date: August 2012 Withdrawal Note: SP 800-107 is superseded in its entirety by the publication of SP 800-107 Revision 1 (August 2012). Superseding Publication(s) The attached publication has been superseded by the following publication(s): Series/Number: NIST Special Publication 800-107 Revision 1 Title: Recommendation for Applications Using Approved Hash Algorithms Author(s): Quynh Dang Publication Date(s): August 2012 URL/DOI: http://dx.doi.org/10.6028/NIST.SP.107r1 Additional Information (if applicable) Contact: Computer Security Division (Information Technology Lab) Latest revision of the SP 800-107 Rev. 1 (as of August 12, 2015) attached publication: Related information: http://csrc.nist.gov/ Withdrawal N/A announcement (link): Date updated: ƵŐƵƐƚϭϮ, 2015 NIST Special Publication 800-107 Recommendation for Applications Using Approved Hash Algorithms Quynh Dang Computer Security Division Information Technology Laboratory C O M P U T E R S E C U R I T Y February 2009 U.S. Department of Commerce Otto J. Wolff, Acting Secretary National Institute of Standards and Technology Patrick D. Gallagher, Deputy Director NIST SP 800-107 Abstract Cryptographic hash functions that compute a fixed- length message digest from arbitrary length messages are widely used for many purposes in information security. This document provides security guidelines for achieving the required or desired security strengths when using cryptographic applications that employ the approved cryptographic hash functions specified in Federal Information Processing Standard (FIPS) 180-3. -
Hashes, Macs & Authenticated Encryption Today's Lecture Hashes
Today’s Lecture • Hashes and Message Authentication Codes Hashes, MACs & • Properties of Hashes and MACs Authenticated Encryption • CBC-MAC, MAC -> HASH (slow), • SHA1, SHA2, SHA3 Tom Chothia • HASH -> MAC, HMAC ICS Lecture 4 • Authenticated Encryption – CCM Hashes Signatures l A hash of any message is a short string • Using RSA Epub(Dpriv(M)) = M generated from that message. • This can be used to sign messages. l The hash of a message is always the same. l Any small change makes the hash totally • Sign a message with the private key and this can be different. verified with the public key. l It is very hard to go from the hash to the message. • Any real crypto suite will not use the same key for encryption and signing. l It is very unlikely that any two different messages have the same hash. – as this can be used to trick people into decrypting. Signatures Uses of Hashing Alice has a signing key Ks • Download/Message verification and wants to sign message M Plain Text • Tying parts of a message together (hash the whole message) Detached Signature: Dks(#(M)) RSA decrypt with key ks SHA hash • Hash message, then sign the hash. • Protect Passwords Signed: M,Dks(#(M)) – Store the hash, not the password 1 Attacks on hashes Birthday Paradox • Preimage Attack: Find a message for a • How many people do you need to ask given hash: very hard. before you find 2 that have the same birthday? • Prefix Collision Attack: a collision attack where the attacker can pick a prefix for • 23 people, gives (23*22)/2 = 253 pairs.