Why Padding Is Required
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
A Type Inference on Executables
A Type Inference on Executables Juan Caballero, IMDEA Software Institute Zhiqiang Lin, University of Texas at Dallas In many applications source code and debugging symbols of a target program are not available, and what we can only access is the program executable. A fundamental challenge with executables is that during compilation critical information such as variables and types is lost. Given that typed variables provide fundamental semantics of a program, for the last 16 years a large amount of research has been carried out on binary code type inference, a challenging task that aims to infer typed variables from executables (also referred to as binary code). In this article we systematize the area of binary code type inference according to its most important dimensions: the applications that motivate its importance, the approaches used, the types that those approaches infer, the implementation of those approaches, and how the inference results are evaluated. We also discuss limitations, point to underdeveloped problems and open challenges, and propose further applications. Categories and Subject Descriptors: D.3.3 [Language Constructs and Features]: Data types and struc- tures; D.4.6 [Operating Systems]: Security and Protection General Terms: Languages, Security Additional Key Words and Phrases: type inference, program executables, binary code analysis ACM Reference Format: Juan Caballero and Zhiqiang Lin, 2015. Type Inference on Executables. ACM Comput. Surv. V, N, Article A (January YYYY), 35 pages. DOI:http://dx.doi.org/10.1145/0000000.0000000 1. INTRODUCTION Being the final deliverable of software, executables (or binary code, as we use both terms interchangeably) are everywhere. They contain the final code that runs on a system and truly represent the program behavior. -
GCM) for Confidentiality And
NIST Special Publication 800-38D Recommendation for Block DRAFT (April, 2006) Cipher Modes of Operation: Galois/Counter Mode (GCM) for Confidentiality and Authentication Morris Dworkin C O M P U T E R S E C U R I T Y Abstract This Recommendation specifies the Galois/Counter Mode (GCM), an authenticated encryption mode of operation for a symmetric key block cipher. KEY WORDS: authentication; block cipher; cryptography; information security; integrity; message authentication code; mode of operation. i Table of Contents 1 PURPOSE...........................................................................................................................................................1 2 AUTHORITY.....................................................................................................................................................1 3 INTRODUCTION..............................................................................................................................................1 4 DEFINITIONS, ABBREVIATIONS, AND SYMBOLS.................................................................................2 4.1 DEFINITIONS AND ABBREVIATIONS .............................................................................................................2 4.2 SYMBOLS ....................................................................................................................................................4 4.2.1 Variables................................................................................................................................................4 -
Targeting Embedded Powerpc
Freescale Semiconductor, Inc. EPPC.book Page 1 Monday, March 28, 2005 9:22 AM CodeWarrior™ Development Studio PowerPC™ ISA Communications Processors Edition Targeting Manual Revised: 28 March 2005 For More Information: www.freescale.com Freescale Semiconductor, Inc. EPPC.book Page 2 Monday, March 28, 2005 9:22 AM Metrowerks, the Metrowerks logo, and CodeWarrior are trademarks or registered trademarks of Metrowerks Corpora- tion in the United States and/or other countries. All other trade names and trademarks are the property of their respective owners. Copyright © 2005 by Metrowerks, a Freescale Semiconductor company. All rights reserved. No portion of this document may be reproduced or transmitted in any form or by any means, electronic or me- chanical, without prior written permission from Metrowerks. Use of this document and related materials are governed by the license agreement that accompanied the product to which this manual pertains. This document may be printed for non-commercial personal use only in accordance with the aforementioned license agreement. If you do not have a copy of the license agreement, contact your Metrowerks representative or call 1-800-377- 5416 (if outside the U.S., call +1-512-996-5300). Metrowerks reserves the right to make changes to any product described or referred to in this document without further notice. Metrowerks makes no warranty, representation or guarantee regarding the merchantability or fitness of its prod- ucts for any particular purpose, nor does Metrowerks assume any liability arising -
Block Cipher Modes
Block Cipher Modes Data and Information Management: ELEN 3015 School of Electrical and Information Engineering, University of the Witwatersrand March 25, 2010 Overview Motivation for Cryptographic Modes Electronic Codebook Mode (ECB) Cipher Block Chaining (CBC) Cipher Feedback Mode (CFB) Output Feedback Mode (OFB) 1. Cryptographic Modes Problem: With block ciphers, same plaintext block always enciphers to the same ciphertext block under the same key 1. Cryptographic Modes Solution: Cryptographic mode: • block cipher • feedback • simple operations Simple operations, as the security lies in the cipher. 1. Cryptographic Modes 1.1 Considerations • The mode should not compromise security of cipher • Mode should conceal patterns in plaintext • Some random starting point is needed • Difficult to manipulate the plaintext by changing ciphertext • Requires multiple messages to be encrypted with same key • No significant impact on efficiency of cipher • Ciphertext same size as plaintext • Fault tolerance - recover from errors 2. Electronic Codebook Mode Uses the block cipher without modifications Same plaintext block encrypts to same ciphertext under same key Each plaintext block is encrypted independently of other plaintext blocks. Corrupted bits only affects one block Dropped/inserted bits cause sync errors ! all subsequent blocks decipher incorrectly 2. Electronic Codebook Mode 2.1 Advantages ECB exhibits `random access property' because plaintext blocks are encrypted independently • Encryption and decryption can be done in any order • Beneficial for databases, records can be added, deleted, modified, encrypted and deleted independently of other records Parallel implementation • Different blocks can simultaneously be decrypted on separate processors Many messages can be encrypted with the same key, since each block is independent. 2. -
Cryptographic Sponge Functions
Cryptographic sponge functions Guido B1 Joan D1 Michaël P2 Gilles V A1 http://sponge.noekeon.org/ Version 0.1 1STMicroelectronics January 14, 2011 2NXP Semiconductors Cryptographic sponge functions 2 / 93 Contents 1 Introduction 7 1.1 Roots .......................................... 7 1.2 The sponge construction ............................... 8 1.3 Sponge as a reference of security claims ...................... 8 1.4 Sponge as a design tool ................................ 9 1.5 Sponge as a versatile cryptographic primitive ................... 9 1.6 Structure of this document .............................. 10 2 Definitions 11 2.1 Conventions and notation .............................. 11 2.1.1 Bitstrings .................................... 11 2.1.2 Padding rules ................................. 11 2.1.3 Random oracles, transformations and permutations ........... 12 2.2 The sponge construction ............................... 12 2.3 The duplex construction ............................... 13 2.4 Auxiliary functions .................................. 15 2.4.1 The absorbing function and path ...................... 15 2.4.2 The squeezing function ........................... 16 2.5 Primary aacks on a sponge function ........................ 16 3 Sponge applications 19 3.1 Basic techniques .................................... 19 3.1.1 Domain separation .............................. 19 3.1.2 Keying ..................................... 20 3.1.3 State precomputation ............................ 20 3.2 Modes of use of sponge functions ......................... -
Interprocedural Analysis of Low-Level Code
TECHNISCHE UNIVERSITAT¨ MUNCHEN¨ Institut fur¨ Informatik Lehrstuhl Informatik II Interprocedural Analysis of Low-Level Code Andrea Flexeder Vollstandiger¨ Abdruck der von der Fakultat¨ fur¨ Informatik der Technischen Universitat¨ Munchen¨ zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. H. M. Gerndt Prufer¨ der Dissertation: 1. Univ.-Prof. Dr. H. Seidl 2. Dr. A. King, University of Kent at Canterbury / UK Die Dissertation wurde am 14.12.2010 bei der Technischen Universitat¨ Munchen¨ eingereicht und durch die Fakultat¨ fur¨ Informatik am 9.6.2011 angenommen. ii Contents 1 Analysis of Low-Level Code 1 1.1 Source versus Binary . 1 1.2 Application Areas . 6 1.3 Executable and Linkable Format (ELF) .................. 12 1.4 Application Binary Interface (ABI)..................... 18 1.5 Assumptions . 24 1.6 Contributions . 24 2 Control Flow Reconstruction 27 2.1 The Concrete Semantics . 31 2.2 Interprocedural Control Flow Reconstruction . 33 2.3 Practical Issues . 39 2.4 Implementation . 43 2.5 Programming Model . 44 3 Classification of Memory Locations 49 3.1 Semantics . 51 3.2 Interprocedural Variable Differences . 58 3.3 Application to Assembly Analysis . 73 4 Reasoning about Array Index Expressions 81 4.1 Linear Two-Variable Equalities . 81 4.2 Application to Assembly Analysis . 88 4.3 Register Coalescing and Locking . 89 5 Tools 91 5.1 Combination of Abstract Domains . 91 5.2 VoTUM . 96 6 Side-Effect Analysis 101 6.1 Semantics . 105 6.2 Analysis of Side-Effects . 108 6.3 Enhancements . 115 6.4 Experimental Results . 118 iii iv CONTENTS 7 Exploiting Alignment for WCET and Data Structures 123 7.1 Alignment Analysis . -
Recommendation for Block Cipher Modes of Operation Methods
NIST Special Publication 800-38A Recommendation for Block 2001 Edition Cipher Modes of Operation Methods and Techniques Morris Dworkin C O M P U T E R S E C U R I T Y ii C O M P U T E R S E C U R I T Y Computer Security Division Information Technology Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899-8930 December 2001 U.S. Department of Commerce Donald L. Evans, Secretary Technology Administration Phillip J. Bond, Under Secretary of Commerce for Technology National Institute of Standards and Technology Arden L. Bement, Jr., Director iii Reports on Information Security Technology The Information Technology Laboratory (ITL) at the National Institute of Standards and Technology (NIST) promotes the U.S. economy and public welfare by providing technical leadership for the Nation’s measurement and standards infrastructure. ITL develops tests, test methods, reference data, proof of concept implementations, and technical analyses to advance the development and productive use of information technology. ITL’s responsibilities include the development of technical, physical, administrative, and management standards and guidelines for the cost-effective security and privacy of sensitive unclassified information in Federal computer systems. This Special Publication 800-series reports on ITL’s research, guidance, and outreach efforts in computer security, and its collaborative activities with industry, government, and academic organizations. Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. -
The Whirlpool Secure Hash Function
Cryptologia, 30:55–67, 2006 Copyright Taylor & Francis Group, LLC ISSN: 0161-1194 print DOI: 10.1080/01611190500380090 The Whirlpool Secure Hash Function WILLIAM STALLINGS Abstract In this paper, we describe Whirlpool, which is a block-cipher-based secure hash function. Whirlpool produces a hash code of 512 bits for an input message of maximum length less than 2256 bits. The underlying block cipher, based on the Advanced Encryption Standard (AES), takes a 512-bit key and oper- ates on 512-bit blocks of plaintext. Whirlpool has been endorsed by NESSIE (New European Schemes for Signatures, Integrity, and Encryption), which is a European Union-sponsored effort to put forward a portfolio of strong crypto- graphic primitives of various types. Keywords advanced encryption standard, block cipher, hash function, sym- metric cipher, Whirlpool Introduction In this paper, we examine the hash function Whirlpool [1]. Whirlpool was developed by Vincent Rijmen, a Belgian who is co-inventor of Rijndael, adopted as the Advanced Encryption Standard (AES); and by Paulo Barreto, a Brazilian crypto- grapher. Whirlpool is one of only two hash functions endorsed by NESSIE (New European Schemes for Signatures, Integrity, and Encryption) [13].1 The NESSIE project is a European Union-sponsored effort to put forward a portfolio of strong cryptographic primitives of various types, including block ciphers, symmetric ciphers, hash functions, and message authentication codes. Background An essential element of most digital signature and message authentication schemes is a hash function. A hash function accepts a variable-size message M as input and pro- duces a fixed-size hash code HðMÞ, sometimes called a message digest, as output. -
Block Cipher and Data Encryption Standard (DES)
Block Cipher and Data Encryption Standard (DES) 2021.03.09 Presented by: Mikail Mohammed Salim Professor 박종혁 Cryptography and Information Security 1 Block Cipher and Data Encryption Standard (DES) Contents • What is Block Cipher? • Padding in Block Cipher • Ideal Block Cipher • What is DES? • DES- Key Discarding Process • Des- 16 rounds of Encryption • How secure is DES? 2 Block Cipher and Data Encryption Standard (DES) What is Block Cipher? • An encryption technique that applies an algorithm with parameters to encrypt blocks of text. • Each plaintext block has an equal length of ciphertext block. • Each output block is the same size as the input block, the block being transformed by the key. • Block size range from 64 -128 bits and process the plaintext in blocks of 64 or 128 bits. • Several bits of information is encrypted with each block. Longer messages are encoded by invoking the cipher repeatedly. 3 Block Cipher and Data Encryption Standard (DES) What is Block Cipher? • Each message (p) grouped in blocks is encrypted (enc) using a key (k) into a Ciphertext (c). Therefore, 푐 = 푒푛푐푘(푝) • The recipient requires the same k to decrypt (dec) the p. Therefore, 푝 = 푑푒푐푘(푐) 4 Block Cipher and Data Encryption Standard (DES) Padding in Block Cipher • Block ciphers process blocks of fixed sizes, such as 64 or 128 bits. The length of plaintexts is mostly not a multiple of the block size. • A 150-bit plaintext provides two blocks of 64 bits each with third block of remaining 22 bits. • The last block of bits needs to be padded up with redundant information so that the length of the final block equal to block size of the scheme. -
Characterization of Padding Rules and Different Variants of MD Hash Functions
Characterization of Padding Rules and Different Variants of MD Hash Functions Mridul Nandi National Institute of Standards and Technology Outline • Introduction to hash function and known Padding Rules. • Thm1 : Suffix-free Padding rule is necessary and sufficient for MD hash functions. • Thm2 : A new suffix-free padding rule handling arbitrary message using log |M| bits and study comparison. • Thm3 : The simplest 10 k padding rule (no length overhead) is secure on a modified MD hash or mMD . • Thm4 : It also works for newly introduced design mode BCM ( Backward Chaining Mode ) and its modification mBCM . Introduction to Hash Function: Security notions, applications and MD iteration and known padding rules Hash Function Arbitrary Length Strings à fixed length strings 101010101010101010101010101010110101010101010010101010101101001001001001010101110100010101110100100001001011100010010001000101101 001010111010001010100010100010100101010101010101010101010000000000011111110110101011010101010101010010110101010101010101111110000 101010101010100101010101010011101010100110101010101010101010101010101010101010101010010111100001110101110000111010001100011110011 101010110101010101010101011001010001010101000010001010111000101110010100000101001110010101010101011101010101010101010101010101010 110101010101010010101010101101001001001001010101110100010101110100100001001011100010010001000101101001010111010001010100010100010 10010101010101010101010101000000000001111111011010101101010101010101001011010101010101010111111000010101010101010010101010101 001 1 10101010011010101010101010101010101010101010101010101001011110000111010111000011101000110001111001110101011010101010101010101 -
Mac OS X ABI Function Call Guide
Mac OS X ABI Function Call Guide 2005-12-06 PowerPC and and the PowerPC logo are Apple Computer, Inc. trademarks of International Business © 2005 Apple Computer, Inc. Machines Corporation, used under license All rights reserved. therefrom. Simultaneously published in the United No part of this publication may be States and Canada. reproduced, stored in a retrieval system, or Even though Apple has reviewed this document, transmitted, in any form or by any means, APPLE MAKES NO WARRANTY OR mechanical, electronic, photocopying, REPRESENTATION, EITHER EXPRESS OR IMPLIED, WITH RESPECT TO THIS recording, or otherwise, without prior DOCUMENT, ITS QUALITY, ACCURACY, written permission of Apple Computer, Inc., MERCHANTABILITY, OR FITNESS FOR A with the following exceptions: Any person PARTICULAR PURPOSE. AS A RESULT, THIS DOCUMENT IS PROVIDED “AS IS,” AND is hereby authorized to store documentation YOU, THE READER, ARE ASSUMING THE on a single computer for personal use only ENTIRE RISK AS TO ITS QUALITY AND ACCURACY. and to print copies of documentation for IN NO EVENT WILL APPLE BE LIABLE FOR personal use provided that the DIRECT, INDIRECT, SPECIAL, INCIDENTAL, documentation contains Apple’s copyright OR CONSEQUENTIAL DAMAGES notice. RESULTING FROM ANY DEFECT OR INACCURACY IN THIS DOCUMENT, even if The Apple logo is a trademark of Apple advised of the possibility of such damages. Computer, Inc. THE WARRANTY AND REMEDIES SET FORTH ABOVE ARE EXCLUSIVE AND IN Use of the “keyboard” Apple logo LIEU OF ALL OTHERS, ORAL OR WRITTEN, EXPRESS OR IMPLIED. No Apple dealer, agent, (Option-Shift-K) for commercial purposes or employee is authorized to make any without the prior written consent of Apple modification, extension, or addition to this may constitute trademark infringement and warranty. -
Secret-Key Encryption Introduction
Secret-Key Encryption Introduction • Encryption is the process of encoding a message in such a way that only authorized parties can read the content of the original message • History of encryption dates back to 1900 BC • Two types of encryption • secret-key encryption : same key for encryption and decryption • pubic-key encryption : different keys for encryption and decryption • We focus on secret-key encryption in this chapter Substitution Cipher • Encryption is done by replacing units of plaintext with ciphertext, according to a fixed system. • Units may be single letters, pairs of letters, triplets of letters, mixtures of the above, and so forth • Decryption simply performs the inverse substitution. • Two typical substitution ciphers: • monoalphabetic - fixed substitution over the entire message • Polyalphabetic - a number of substitutions at different positions in the message Monoalphabetic Substitution Cipher • Encryption and decryption Breaking Monoalphabetic Substitution Cipher • Frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. • Common letters : T, A, E, I, O • Common 2-letter combinations (bigrams): TH, HE, IN, ER • Common 3-letter combinations (trigrams): THE, AND, and ING Breaking Monoalphabetic Substitution Cipher • Letter Frequency Analysis results: Breaking Monoalphabetic Substitution Cipher • Bigram Frequency Analysis results: Breaking Monoalphabetic Substitution Cipher • Trigram Frequency analysis results: Breaking Monoalphabetic Substitution Cipher • Applying the partial mappings… Data Encryption Standard (DES) • DES is a block cipher - can only encrypt a block of data • Block size for DES is 64 bits • DES uses 56-bit keys although a 64-bit key is fed into the algorithm • Theoretical attacks were identified. None was practical enough to cause major concerns.