Digital Signatures. Meka N.L.Sneha. Indiana State University. October 2015

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Digital Signatures. Meka N.L.Sneha. Indiana State University. nmeka@sycamores.indstate.edu. October 2015"

Transcription

1 Digital Signatures Meka N.L.Sneha Indiana State University October Introduction Digital Signatures are the most trusted way to get documents signed online. A digital signature is signing an electronic document which ensures the authenticity, non-repudiation and data integrity of signed electronic documents. A Digital Signature is like a handwritten signature which is impossible to forge and is sent as a part of an electronic document. Organizations are able to shorten processing times with cutting costs and improving collaboration and efficiency after using Digital Signatures. An electronic document which is to be signed is issued to the signer. To create digital signature this message is crunch down into few lines by a process called hashing. Then the hash is encrypted using signers private key. The encrypted hash along with the message is the digital signature. This hashed data enables others to validate the integrity of the data by decrypting the hashed data using signers public key. 2 History Long before digital signatures, paper signature were used to sign important contracts and documents. As people began doing business across the world, it became necessary to find other ways to sign the agreement. Whitfield Diffie and Martin Hellman first described the idea of Digital Signature scheme but they only conjectured that such schemes only existed. It was published in Soon after Ronald Rivest, Adi Shamir and Len Adleman invented the RSA algorithm. This could be used to create primitive Digital Signatures. The first widely software package to offer digital signature was Lotus 1.0. It was released in 1989 and uses RSA algorithm. In many countries including United States have the same legal significance as the handwritten signed documents. A number of states had already published 1

2 their own electronic signatures regulations by the time E-Sign Act was passed. Soon after Utah passed its digital signature act in 1995, California and other handful of states created similar guidelines. The American Bar Association has set up its own set of digital signatures guidelines in These guidelines were for attorneys and other legal professionals determine the integrity and authenticity of digital signatures. Model Law on Electronic Commerce (MLEC) was developed in 1996 with the purpose of encouraging e-commerce by providing a series of internationally acceptable rules. In 2000, E-Sign Act wass passed. The guidelines in the E-Sign Act became the most recognized guidelines in the world. The creation of the digital signatures let businesses send signed contracts across the globe in seconds. 3 Description A digital signature is equivalent to a written signature but is more secured than a written signature and cannot be forged. A digital signature algorithm consists of a digital signature generation process and a digital signature verification process. A signatory uses generation process to generate digital signature and verifier uses verification process to verify the authenticity. A signatory has a public key and private key. The claimed signatory is the only entity to have authorization to use the private key. Private key is used to generate digital signatures and public key is used in signature verification process. CAs shall have assurance of the public key. 3.1 Digital Signature Generation A digital signature key pair is generated by itself or by obtaining the key pair from a trusted party as specified for the digital signature algorithm. The intended signatory shall obtain assurance of validity of public key and assurance that the entity possesses the private key after obtaining the key pair. To generate a digital signature, the information to be signed is crunch down into message digest using an appropriate approved hashing algorithm. Based on digital signature algorithm, this message digest, private key and any other information required by the signature generation process, a digital signature shall be generated. The digital signature is appended with the message and is sent to the recipient. The following section describes the hashing algorithms used to generate message digest Hashing Algorithm Hashing algorithms are used to generate message digests. These message digests can be used to detect whether the messages have been altered since the digests were generated. The secured hashing algorithms are SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224 and SHA-512/256. All of these algorithms are iterative, one-way hash functions that generate a message digest. The hash 2

3 algorithms are secure because, it is infeasible to obtain the original message that corresponds to a message digest and every message produces a different message digest. Each algorithm consists of two stages, that is, preprocessing and hash computation. Hash computation produces a message schedule from padded message and uses that schedule to determine series of hash values. The final hash value is used to generate message digest. Pre-processing Preprocessing involves three steps: padding the message, parsing the padded message and setting the initial hash value. Padding the Message The purpose of padding is to make sure that the padded message is a multiple of 512 or 1024 bits depending on the hashing algorithm. Consider that the length of the message M is l bits. The message is padded with a one bit followed by k zero bits and then the message length. Appending 0 s to the end should be done until the length of the message is either congruent to 448 mod 512 or 896 mod The padded message should be a multiple of 512 or 1024 bits. For SHA-1, SHA-224 and SHA-256, the length of the padded message should be a multiple of 512 bits. For SHA-384, SHA-512, SHA-512/224 and SHA- 512/256, the length of the padded message should be a multiple of 1024 bits. Parsing the Message The message and the padded message are parsed into N m-blocks. For SHA- 1, SHA-224 and SHA-256, the message and its padding are parsed into N 512-bit blocks, M (1), M (2),..., M (N). The 512-bits of the block can be expressed as sixteen 32-bit words. These bits of message block i are denoted as M (i) 0, M (i) 1 and so on up to M (i) 15. For SHA-384, SHA-512, SHA-512/224 and SHA-512/256, the message and its padding are parsed into N 1024-bit blocks, M (1), M (2),..., M (N) bits of the block can be expressed as sixteen 64-bit words. These 64 bits of message block i are denoted as M (i) 0, M (i) 1 and so on up to M (i) 15. Setting the Initial Value For each of the hash algorithms, before hash computation begins the initial value H (0) must be set. The size and number of words in H (0) depends on the message digest size. Hash Computation For each hashing algorithm, hash computation uses different functions and constants are defined. Each message block is processed in order. Firstly, the message schedule is prepared, that is, each message block is put through a little function that creates 80 words. Then we initialize the working variables a, b, c,... h. Working variables are the w-bit words which are used in the computation of hash value H (i). Then the i th intermediate hash value is computed. These 3

4 steps are repeated through a total of N times to generate message digest of the message M Digital Signature Algorithm A message digest is generated using hashing function. Digital signature algorithm is used to encrypt the message digest with the signatory private key. The result is the digital signature which is then appended to the message. The hashed data represents that the document has been signed. The approved techniques used for digital signature generation, and for the verification and validation of those signatures are Digital Signature Algorithm (DSA), RSA digital signature algorithm and Elliptic Curve Digital Signature Algorithm (ECDSA). Digital Signature Algorithm (DSA) A DSA digital signature is generated using a set of domain parameters, a private key, a per-message secret number k, data to be signed and a hash function. Each signatory has a private key and a public key. The private key is used for a fixed period of time and public key is used as long as the digital signature is verified. The domain parameters may be public. A user with the domain parameters has the assurance of validity before using them. The domain parameters are p (prime modulus), q (prime divisor of (p-1)), g (generator of the subgroup of order q mod p), x(private key), y(public key), k (secret number unique to each message).these domain parameters are either generated by the Trusted Third Party (TTP) or by itself. DSA requires private key to generate digital signature with respect to a particular set of domain parameters. DSA per-message secret random number is generated prior to the digital signature generation. An approved hash function is used for the generation of digital signatures. DSA Signature Generation The bit length of q is denoted by N and the minimum of the positive integers N is denoted by min (N, outlen), where outlen is the bit length of the message digest. The digital signature consists of pair of numbers r and s that is computed using following equations: r = (g k mod p) mod q. z = the leftmost min(n, outlen) bits of Hash(M). s = (k 1 (z + xr)) mod q. When computing s, string z is obtained from Hash (M) which is converted to an integer. Parameter r can be computed whenever k, p, q and g are available. The signature is sent to the receiver along with the message. RSA Digital Signature Algorithm RSA digital signature key pair consists of RSA private key which is used to compute the digital signature and can be used only for one digital signature scheme. RSA private key consists of modulus n, which is the product of two 4

5 positive prime integers p and q and a private key exponent d and public key exponent e. The two integers p and q and the private key exponent d are kept secret. The RSA private key is the pair of values (n, d) and is used to generate digital signatures. Elliptic Curve Digital Signature Algorithm (ECDSA) ECDSA is the elliptic curve analog of DSA. ECDSA keys are not used for any purpose. An ECDSA key pair consists of a private key d and public key Q. The private key is used for a period of time and the public key is used as long as the digital signature is generated. A digital signature key pair d and Q is generated for domain parameters. ECDSA requires that private key used for generating digital signature be generated with respect to a particular set of domain parameters. These domain parameters may be public. An approved hash function is used during the generation of ECDSA parameters. A new secret number k is generated before generation of each digital signature. ECDSA Digital Signature Generation An ECDSA digital signature is generated using domain parameters, a private key, a per-message secret number, an approved hash function and an approved random number generator. 3.2 Digital Signature Verification The verification process is used to verify the authenticity of the signature. The public key is used in the verification process and the public key need not be kept secret. Both the message and digital signature are made available for verification. By an approved hash function, message is converted to a fixedlength representation, that is, message digest. The digital signature is decrypted into message digest using signatory public key. If the message digest is same as the message digest created when the signature is decrypted, it means that the digital signature is not altered. Digital signature validation needs to verify the digital signature and also need to obtain the appropriate assurances. These assurances are obtain the assurance of the claimed signatory s identity, assurance of domain parameter validity, assurance of the validity of the owner s public key and assurance that the owner possesses the private key Hashing Algorithm Approved hash functions are described in the section Digital Signature Algorithm In signature verification process, digital signature algorithm is used for the decryption of message digest with the signatory public key. This message digest is generated using approved hash functions. The techniques used for verification and validation of the digital signatures are Digital Signature Algorithm (DSA), 5

6 RSA digital signature algorithm and Elliptic Curve Digital Signature Algorithm (ECDSA). DSA Signature Verification and Validation Prior to verifying the signature, the domain parameters, the signatory s public key and identity are made available to the verifier. The public key is obtained from a trusted entity such as Certificate Authority (CA). The signature verification can be verified by the signatory, the intended recipient or any other party using the signatory s public key. A signatory verifies the signed message before sending the digital signature to the intended recipient. The recipient or any other party verifies the signature to determine the authenticity. RSA Digital Signature Verification RSA digital signature key pair consists of private key used to compute the digital signature and public key used to verify a digital signature. The public key consists of a modulus n which is the product of two prime integer s p and q and public key exponent e. The RSA public key is the pair of values (n, e) and is used to verify the signed data. The modulus n and public key exponent e may be made known to anyone. When the public key exponent e is odd, the digital signature algorithm is commonly known as RSA and when the public signature verification exponent e is even, the algorithm is commonly known as Rabin-Williams. ECDSA Digital Signature Verification An ECDSA digital signature is verified using the same domain parameters and hash function that is used while generation of digital signature. 4 Conclusion The digital signature technology is vastly utilized in modern life and innovation. The security of the digital signatures depends on the security of the keys that are used to create and verify them. The digital signature algorithms are used in different purposes such as websites, mobile phones, software certification, business bargains etc. The trustworthiness of a certification authority can be obtained by higher certification authorities. Once non-repudiation has been accomplished, then only the electronic business has been expected to successfully taken up. 6

7 References [1] FIPS PUB 180-4, Secure Hash Standard (SHS). [2] FIPS PUB 186-3, Digital Signature Standard (DSS). [3] https://technet.microsoft.com/en-us/library/cc aspx [4] https://tools.ietf.org/html/rfc3174 [5] NIST SP , Randomized Hashing for Digital Signatures. 7

Digital Signature Standard (DSS)

Digital Signature Standard (DSS) FIPS PUB 186-4 FEDERAL INFORMATION PROCESSING STANDARDS PUBLICATION Digital Signature Standard (DSS) CATEGORY: COMPUTER SECURITY SUBCATEGORY: CRYPTOGRAPHY Information Technology Laboratory National Institute

More information

ARCHIVED PUBLICATION

ARCHIVED PUBLICATION ARCHIVED PUBLICATION The attached publication, FIPS Publication 186-3 (dated June 2009), was superseded on July 19, 2013 and is provided here only for historical purposes. For the most current revision

More information

Digital Signature. Raj Jain. Washington University in St. Louis

Digital Signature. Raj Jain. Washington University in St. Louis Digital Signature Raj Jain Washington University in Saint Louis Saint Louis, MO 63130 Jain@cse.wustl.edu Audio/Video recordings of this lecture are available at: http://www.cse.wustl.edu/~jain/cse571-11/

More information

The Mathematics of the RSA Public-Key Cryptosystem

The Mathematics of the RSA Public-Key Cryptosystem The Mathematics of the RSA Public-Key Cryptosystem Burt Kaliski RSA Laboratories ABOUT THE AUTHOR: Dr Burt Kaliski is a computer scientist whose involvement with the security industry has been through

More information

Implementation and Comparison of Various Digital Signature Algorithms. -Nazia Sarang Boise State University

Implementation and Comparison of Various Digital Signature Algorithms. -Nazia Sarang Boise State University Implementation and Comparison of Various Digital Signature Algorithms -Nazia Sarang Boise State University What is a Digital Signature? A digital signature is used as a tool to authenticate the information

More information

Randomized Hashing for Digital Signatures

Randomized Hashing for Digital Signatures NIST Special Publication 800-106 Randomized Hashing for Digital Signatures 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

More information

A New Generic Digital Signature Algorithm

A New Generic Digital Signature Algorithm Groups Complex. Cryptol.? (????), 1 16 DOI 10.1515/GCC.????.??? de Gruyter???? A New Generic Digital Signature Algorithm Jennifer Seberry, Vinhbuu To and Dongvu Tonien Abstract. In this paper, we study

More information

ACTA UNIVERSITATIS APULENSIS No 13/2007 MATHEMATICAL FOUNDATION OF DIGITAL SIGNATURES. Daniela Bojan and Sidonia Vultur

ACTA UNIVERSITATIS APULENSIS No 13/2007 MATHEMATICAL FOUNDATION OF DIGITAL SIGNATURES. Daniela Bojan and Sidonia Vultur ACTA UNIVERSITATIS APULENSIS No 13/2007 MATHEMATICAL FOUNDATION OF DIGITAL SIGNATURES Daniela Bojan and Sidonia Vultur Abstract.The new services available on the Internet have born the necessity of a permanent

More information

1720 - Forward Secrecy: How to Secure SSL from Attacks by Government Agencies

1720 - Forward Secrecy: How to Secure SSL from Attacks by Government Agencies 1720 - Forward Secrecy: How to Secure SSL from Attacks by Government Agencies Dave Corbett Technical Product Manager Implementing Forward Secrecy 1 Agenda Part 1: Introduction Why is Forward Secrecy important?

More information

Lukasz Pater CMMS Administrator and Developer

Lukasz Pater CMMS Administrator and Developer Lukasz Pater CMMS Administrator and Developer EDMS 1373428 Agenda Introduction Why do we need asymmetric ciphers? One-way functions RSA Cipher Message Integrity Examples Secure Socket Layer Single Sign

More information

Digital Signature For Text File

Digital Signature For Text File Digital Signature For Text File Ayad Ibrahim Abdulsada Dept. of Computer Science, College of Education, University of Basrah, Basrah, Iraq. E-mail: mraiadibraheem@yahoo.com Abstract: Digital signatures

More information

Network Security. Abusayeed Saifullah. CS 5600 Computer Networks. These slides are adapted from Kurose and Ross 8-1

Network Security. Abusayeed Saifullah. CS 5600 Computer Networks. These slides are adapted from Kurose and Ross 8-1 Network Security Abusayeed Saifullah CS 5600 Computer Networks These slides are adapted from Kurose and Ross 8-1 Public Key Cryptography symmetric key crypto v requires sender, receiver know shared secret

More information

Authentication requirement Authentication function MAC Hash function Security of

Authentication requirement Authentication function MAC Hash function Security of UNIT 3 AUTHENTICATION Authentication requirement Authentication function MAC Hash function Security of hash function and MAC SHA HMAC CMAC Digital signature and authentication protocols DSS Slides Courtesy

More information

Public Key (asymmetric) Cryptography

Public Key (asymmetric) Cryptography Public-Key Cryptography UNIVERSITA DEGLI STUDI DI PARMA Dipartimento di Ingegneria dell Informazione Public Key (asymmetric) Cryptography Luca Veltri (mail.to: luca.veltri@unipr.it) Course of Network Security,

More information

Computer Security: Principles and Practice

Computer Security: Principles and Practice Computer Security: Principles and Practice Chapter 20 Public-Key Cryptography and Message Authentication First Edition by William Stallings and Lawrie Brown Lecture slides by Lawrie Brown Public-Key Cryptography

More information

Authentication, digital signatures, PRNG

Authentication, digital signatures, PRNG Multimedia Security Authentication, digital signatures, PRNG Mauro Barni University of Siena Beyond confidentiality Up to now, we have been concerned with protecting message content (i.e. confidentiality)

More information

Final Exam. IT 4823 Information Security Administration. Rescheduling Final Exams. Kerberos. Idea. Ticket

Final Exam. IT 4823 Information Security Administration. Rescheduling Final Exams. Kerberos. Idea. Ticket IT 4823 Information Security Administration Public Key Encryption Revisited April 5 Notice: This session is being recorded. Lecture slides prepared by Dr Lawrie Brown for Computer Security: Principles

More information

Digital Signatures. Murat Kantarcioglu. Based on Prof. Li s Slides. Digital Signatures: The Problem

Digital Signatures. Murat Kantarcioglu. Based on Prof. Li s Slides. Digital Signatures: The Problem Digital Signatures Murat Kantarcioglu Based on Prof. Li s Slides Digital Signatures: The Problem Consider the real-life example where a person pays by credit card and signs a bill; the seller verifies

More information

CSCE 465 Computer & Network Security

CSCE 465 Computer & Network Security CSCE 465 Computer & Network Security Instructor: Dr. Guofei Gu http://courses.cse.tamu.edu/guofei/csce465/ Public Key Cryptogrophy 1 Roadmap Introduction RSA Diffie-Hellman Key Exchange Public key and

More information

CRYPTOGRAPHY IN NETWORK SECURITY

CRYPTOGRAPHY IN NETWORK SECURITY ELE548 Research Essays CRYPTOGRAPHY IN NETWORK SECURITY AUTHOR: SHENGLI LI INSTRUCTOR: DR. JIEN-CHUNG LO Date: March 5, 1999 Computer network brings lots of great benefits and convenience to us. We can

More information

Secure Network Communication Part II II Public Key Cryptography. Public Key Cryptography

Secure Network Communication Part II II Public Key Cryptography. Public Key Cryptography Kommunikationssysteme (KSy) - Block 8 Secure Network Communication Part II II Public Key Cryptography Dr. Andreas Steffen 2000-2001 A. Steffen, 28.03.2001, KSy_RSA.ppt 1 Secure Key Distribution Problem

More information

Overview of Public-Key Cryptography

Overview of Public-Key Cryptography CS 361S Overview of Public-Key Cryptography Vitaly Shmatikov slide 1 Reading Assignment Kaufman 6.1-6 slide 2 Public-Key Cryptography public key public key? private key Alice Bob Given: Everybody knows

More information

Transitions: Recommendation for Transitioning the Use of Cryptographic Algorithms and Key Lengths

Transitions: Recommendation for Transitioning the Use of Cryptographic Algorithms and Key Lengths NIST Special Publication 800-131A Transitions: Recommendation for Transitioning the Use of Cryptographic Algorithms and Key Lengths Elaine Barker and Allen Roginsky Computer Security Division Information

More information

Overview of Cryptographic Tools for Data Security. Murat Kantarcioglu

Overview of Cryptographic Tools for Data Security. Murat Kantarcioglu UT DALLAS Erik Jonsson School of Engineering & Computer Science Overview of Cryptographic Tools for Data Security Murat Kantarcioglu Pag. 1 Purdue University Cryptographic Primitives We will discuss the

More information

Outline. Computer Science 418. Digital Signatures: Observations. Digital Signatures: Definition. Definition 1 (Digital signature) Digital Signatures

Outline. Computer Science 418. Digital Signatures: Observations. Digital Signatures: Definition. Definition 1 (Digital signature) Digital Signatures Outline Computer Science 418 Digital Signatures Mike Jacobson Department of Computer Science University of Calgary Week 12 1 Digital Signatures 2 Signatures via Public Key Cryptosystems 3 Provable 4 Mike

More information

Evaluation of Digital Signature Process

Evaluation of Digital Signature Process Evaluation of Digital Signature Process Emil SIMION, Ph. D. email: esimion@fmi.unibuc.ro Agenda Evaluation of digital signatures schemes: evaluation criteria; security evaluation; security of hash functions;

More information

USING ENCRYPTION TO PROTECT SENSITIVE INFORMATION Commonwealth Office of Technology Security Month Seminars October 29, 2013

USING ENCRYPTION TO PROTECT SENSITIVE INFORMATION Commonwealth Office of Technology Security Month Seminars October 29, 2013 USING ENCRYPTION TO PROTECT SENSITIVE INFORMATION Commonwealth Office of Technology Security Month Seminars Alternate Title? Boy, am I surprised. The Entrust guy who has mentioned PKI during every Security

More information

Software Implementation of Gong-Harn Public-key Cryptosystem and Analysis

Software Implementation of Gong-Harn Public-key Cryptosystem and Analysis Software Implementation of Gong-Harn Public-key Cryptosystem and Analysis by Susana Sin A thesis presented to the University of Waterloo in fulfilment of the thesis requirement for the degree of Master

More information

Public Key Cryptography Overview

Public Key Cryptography Overview Ch.20 Public-Key Cryptography and Message Authentication I will talk about it later in this class Final: Wen (5/13) 1630-1830 HOLM 248» give you a sample exam» Mostly similar to homeworks» no electronic

More information

Digital Certificates (Public Key Infrastructure) Reshma Afshar Indiana State University

Digital Certificates (Public Key Infrastructure) Reshma Afshar Indiana State University Digital Certificates (Public Key Infrastructure) Reshma Afshar Indiana State University October 2015 1 List of Figures Contents 1 Introduction 1 2 History 2 3 Public Key Infrastructure (PKI) 3 3.1 Certificate

More information

An Approach to Shorten Digital Signature Length

An Approach to Shorten Digital Signature Length Computer Science Journal of Moldova, vol.14, no.342, 2006 An Approach to Shorten Digital Signature Length Nikolay A. Moldovyan Abstract A new method is proposed to design short signature schemes based

More information

SECURITY IN NETWORKS

SECURITY IN NETWORKS SECURITY IN NETWORKS GOALS Understand principles of network security: Cryptography and its many uses beyond confidentiality Authentication Message integrity Security in practice: Security in application,

More information

Network Security. Gaurav Naik Gus Anderson. College of Engineering. Drexel University, Philadelphia, PA. Drexel University. College of Engineering

Network Security. Gaurav Naik Gus Anderson. College of Engineering. Drexel University, Philadelphia, PA. Drexel University. College of Engineering Network Security Gaurav Naik Gus Anderson, Philadelphia, PA Lectures on Network Security Feb 12 (Today!): Public Key Crypto, Hash Functions, Digital Signatures, and the Public Key Infrastructure Feb 14:

More information

Implementation of Elliptic Curve Digital Signature Algorithm

Implementation of Elliptic Curve Digital Signature Algorithm Implementation of Elliptic Curve Digital Signature Algorithm Aqeel Khalique Kuldip Singh Sandeep Sood Department of Electronics & Computer Engineering, Indian Institute of Technology Roorkee Roorkee, India

More information

Digital Signatures. (Note that authentication of sender is also achieved by MACs.) Scan your handwritten signature and append it to the document?

Digital Signatures. (Note that authentication of sender is also achieved by MACs.) Scan your handwritten signature and append it to the document? Cryptography Digital Signatures Professor: Marius Zimand Digital signatures are meant to realize authentication of the sender nonrepudiation (Note that authentication of sender is also achieved by MACs.)

More information

CIS 6930 Emerging Topics in Network Security. Topic 2. Network Security Primitives

CIS 6930 Emerging Topics in Network Security. Topic 2. Network Security Primitives CIS 6930 Emerging Topics in Network Security Topic 2. Network Security Primitives 1 Outline Absolute basics Encryption/Decryption; Digital signatures; D-H key exchange; Hash functions; Application of hash

More information

159.334 Computer Networks. Network Security 1. Professor Richard Harris School of Engineering and Advanced Technology

159.334 Computer Networks. Network Security 1. Professor Richard Harris School of Engineering and Advanced Technology Network Security 1 Professor Richard Harris School of Engineering and Advanced Technology Presentation Outline Overview of Identification and Authentication The importance of identification and Authentication

More information

7! Cryptographic Techniques! A Brief Introduction

7! Cryptographic Techniques! A Brief Introduction 7! Cryptographic Techniques! A Brief Introduction 7.1! Introduction to Cryptography! 7.2! Symmetric Encryption! 7.3! Asymmetric (Public-Key) Encryption! 7.4! Digital Signatures! 7.5! Public Key Infrastructures

More information

Review of methods for secret sharing in cloud computing

Review of methods for secret sharing in cloud computing Review of methods for secret sharing in cloud computing Dnyaneshwar Supe Amit Srivastav Dr. Rajesh S. Prasad Abstract:- Cloud computing provides various IT services. Many companies especially those who

More information

I N F O R M A T I O N S E C U R I T Y

I N F O R M A T I O N S E C U R I T Y NIST Special Publication 800-78-3 DRAFT Cryptographic Algorithms and Key Sizes for Personal Identity Verification W. Timothy Polk Donna F. Dodson William E. Burr Hildegard Ferraiolo David Cooper I N F

More information

2. Cryptography 2.4 Digital Signatures

2. Cryptography 2.4 Digital Signatures DI-FCT-UNL Computer and Network Systems Security Segurança de Sistemas e Redes de Computadores 2010-2011 2. Cryptography 2.4 Digital Signatures 2010, Henrique J. Domingos, DI/FCT/UNL 2.4 Digital Signatures

More information

An Introduction to Cryptography as Applied to the Smart Grid

An Introduction to Cryptography as Applied to the Smart Grid An Introduction to Cryptography as Applied to the Smart Grid Jacques Benoit, Cooper Power Systems Western Power Delivery Automation Conference Spokane, Washington March 2011 Agenda > Introduction > Symmetric

More information

Recommendation for Applications Using Approved Hash Algorithms

Recommendation for Applications Using Approved Hash Algorithms 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

More information

Cryptographic hash functions and MACs Solved Exercises for Cryptographic Hash Functions and MACs

Cryptographic hash functions and MACs Solved Exercises for Cryptographic Hash Functions and MACs Cryptographic hash functions and MACs Solved Exercises for Cryptographic Hash Functions and MACs Enes Pasalic University of Primorska Koper, 2014 Contents 1 Preface 3 2 Problems 4 2 1 Preface This is a

More information

Notes on Network Security Prof. Hemant K. Soni

Notes on Network Security Prof. Hemant K. Soni Chapter 9 Public Key Cryptography and RSA Private-Key Cryptography traditional private/secret/single key cryptography uses one key shared by both sender and receiver if this key is disclosed communications

More information

Lecture 9: Application of Cryptography

Lecture 9: Application of Cryptography Lecture topics Cryptography basics Using SSL to secure communication links in J2EE programs Programmatic use of cryptography in Java Cryptography basics Encryption Transformation of data into a form that

More information

Introduction to Cryptography CS 355

Introduction to Cryptography CS 355 Introduction to Cryptography CS 355 Lecture 30 Digital Signatures CS 355 Fall 2005 / Lecture 30 1 Announcements Wednesday s lecture cancelled Friday will be guest lecture by Prof. Cristina Nita- Rotaru

More information

An Introduction to digital signatures

An Introduction to digital signatures An Introduction to digital signatures This document is an extract from the book Ecommerce - Legal Issues authored by Rohas Nagpal. This book is available as courseware for the Diploma in Cyber Law and

More information

Guideline for Implementing Cryptography In the Federal Government

Guideline for Implementing Cryptography In the Federal Government NIST Special Publication 800-21 [Second Edition] Guideline for Implementing Cryptography In the Federal Government Elaine B. Barker, William C. Barker, Annabelle Lee I N F O R M A T I O N S E C U R I T

More information

Network Security (2) CPSC 441 Department of Computer Science University of Calgary

Network Security (2) CPSC 441 Department of Computer Science University of Calgary Network Security (2) CPSC 441 Department of Computer Science University of Calgary 1 Friends and enemies: Alice, Bob, Trudy well-known in network security world Bob, Alice (lovers!) want to communicate

More information

In accordance with article 11 of the Law on Electronic Signature (Official Gazette of the Republic of Serbia No. 135/04), REGULATION

In accordance with article 11 of the Law on Electronic Signature (Official Gazette of the Republic of Serbia No. 135/04), REGULATION In accordance with article 11 of the Law on Electronic Signature (Official Gazette of the Republic of Serbia No. 135/04), the Minister of Telecommunications and Information Society hereby promulgates REGULATION

More information

Cryptography and Network Security Chapter 9

Cryptography and Network Security Chapter 9 Cryptography and Network Security Chapter 9 Fifth Edition by William Stallings Lecture slides by Lawrie Brown (with edits by RHB) Chapter 9 Public Key Cryptography and RSA Every Egyptian received two names,

More information

Improvement of digital signature with message recovery using self-certified public keys and its variants

Improvement of digital signature with message recovery using self-certified public keys and its variants Applied Mathematics and Computation 159 (2004) 391 399 www.elsevier.com/locate/amc Improvement of digital signature with message recovery using self-certified public keys and its variants Zuhua Shao Department

More information

Principles of Public Key Cryptography. Applications of Public Key Cryptography. Security in Public Key Algorithms

Principles of Public Key Cryptography. Applications of Public Key Cryptography. Security in Public Key Algorithms Principles of Public Key Cryptography Chapter : Security Techniques Background Secret Key Cryptography Public Key Cryptography Hash Functions Authentication Chapter : Security on Network and Transport

More information

Understanding and Integrating KODAK Picture Authentication Cameras

Understanding and Integrating KODAK Picture Authentication Cameras Understanding and Integrating KODAK Picture Authentication Cameras Introduction Anyone familiar with imaging software such as ADOBE PHOTOSHOP can appreciate how easy it is manipulate digital still images.

More information

Cryptosystems. Bob wants to send a message M to Alice. Symmetric ciphers: Bob and Alice both share a secret key, K.

Cryptosystems. Bob wants to send a message M to Alice. Symmetric ciphers: Bob and Alice both share a secret key, K. Cryptosystems Bob wants to send a message M to Alice. Symmetric ciphers: Bob and Alice both share a secret key, K. C= E(M, K), Bob sends C Alice receives C, M=D(C,K) Use the same key to decrypt. Public

More information

Overview of CSS SSL. SSL Cryptography Overview CHAPTER

Overview of CSS SSL. SSL Cryptography Overview CHAPTER CHAPTER 1 Secure Sockets Layer (SSL) is an application-level protocol that provides encryption technology for the Internet, ensuring secure transactions such as the transmission of credit card numbers

More information

Introduction to Computer Security

Introduction to Computer Security Introduction to Computer Security Hash Functions and Digital Signatures Pavel Laskov Wilhelm Schickard Institute for Computer Science Integrity objective in a wide sense Reliability Transmission errors

More information

Chapter 7: Network security

Chapter 7: Network security Chapter 7: Network security Foundations: what is security? cryptography authentication message integrity key distribution and certification Security in practice: application layer: secure e-mail transport

More information

ID-based Cryptography and Smart-Cards

ID-based Cryptography and Smart-Cards ID-based Cryptography and Smart-Cards Survol des techniques cryptographiques basées sur l identité et implémentation sur carte à puce The Need for Cryptography Encryption! Transform a message so that only

More information

Signature Schemes. CSG 252 Fall 2006. Riccardo Pucella

Signature Schemes. CSG 252 Fall 2006. Riccardo Pucella Signature Schemes CSG 252 Fall 2006 Riccardo Pucella Signatures Signatures in real life have a number of properties They specify the person responsible for a document E.g. that it has been produced by

More information

Safeguarding Data Using Encryption. Matthew Scholl & Andrew Regenscheid Computer Security Division, ITL, NIST

Safeguarding Data Using Encryption. Matthew Scholl & Andrew Regenscheid Computer Security Division, ITL, NIST Safeguarding Data Using Encryption Matthew Scholl & Andrew Regenscheid Computer Security Division, ITL, NIST What is Cryptography? Cryptography: The discipline that embodies principles, means, and methods

More information

Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography (Revised)

Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography (Revised) NIST Special Publication 800-56A Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography (Revised) Elaine Barker, Don Johnson, and Miles Smid C O M P U T E R S E C

More information

Network Security. Security Attacks. Normal flow: Interruption: 孫 宏 民 hmsun@cs.nthu.edu.tw Phone: 03-5742968 國 立 清 華 大 學 資 訊 工 程 系 資 訊 安 全 實 驗 室

Network Security. Security Attacks. Normal flow: Interruption: 孫 宏 民 hmsun@cs.nthu.edu.tw Phone: 03-5742968 國 立 清 華 大 學 資 訊 工 程 系 資 訊 安 全 實 驗 室 Network Security 孫 宏 民 hmsun@cs.nthu.edu.tw Phone: 03-5742968 國 立 清 華 大 學 資 訊 工 程 系 資 訊 安 全 實 驗 室 Security Attacks Normal flow: sender receiver Interruption: Information source Information destination

More information

I N F O R M A T I O N S E C U R I T Y

I N F O R M A T I O N S E C U R I T Y NIST Special Publication 800-78-2 DRAFT Cryptographic Algorithms and Key Sizes for Personal Identity Verification W. Timothy Polk Donna F. Dodson William. E. Burr I N F O R M A T I O N S E C U R I T Y

More information

Digital signatures are one of the most important inventions/applications of modern cryptography.

Digital signatures are one of the most important inventions/applications of modern cryptography. CHAPTER 7: DIGITAL SIGNATURES Digital signatures are one of the most important inventions/applications of modern cryptography. Part VII Digital signatures The problem is how can a user sign (electronically)

More information

Cryptography and Network Security

Cryptography and Network Security Cryptography and Network Security Fifth Edition by William Stallings Chapter 9 Public Key Cryptography and RSA Private-Key Cryptography traditional private/secret/single key cryptography uses one key shared

More information

Recommendation for Cryptographic Key Generation

Recommendation for Cryptographic Key Generation NIST Special Publication 800-133 Recommendation for Cryptographic Key Generation Elaine Barker Allen Roginsky http://dx.doi.org/10.6028/nist.sp.800-133 C O M P U T E R S E C U R I T Y NIST Special Publication

More information

Communications security

Communications security University of Roma Sapienza DIET Communications security Lecturer: Andrea Baiocchi DIET - University of Roma La Sapienza E-mail: andrea.baiocchi@uniroma1.it URL: http://net.infocom.uniroma1.it/corsi/index.htm

More information

NEW DIGITAL SIGNATURE PROTOCOL BASED ON ELLIPTIC CURVES

NEW DIGITAL SIGNATURE PROTOCOL BASED ON ELLIPTIC CURVES NEW DIGITAL SIGNATURE PROTOCOL BASED ON ELLIPTIC CURVES Ounasser Abid 1, Jaouad Ettanfouhi 2 and Omar Khadir 3 1,2,3 Laboratory of Mathematics, Cryptography and Mechanics, Department of Mathematics, Fstm,

More information

Network Security. Computer Networking Lecture 08. March 19, 2012. HKU SPACE Community College. HKU SPACE CC CN Lecture 08 1/23

Network Security. Computer Networking Lecture 08. March 19, 2012. HKU SPACE Community College. HKU SPACE CC CN Lecture 08 1/23 Network Security Computer Networking Lecture 08 HKU SPACE Community College March 19, 2012 HKU SPACE CC CN Lecture 08 1/23 Outline Introduction Cryptography Algorithms Secret Key Algorithm Message Digest

More information

RSA Attacks. By Abdulaziz Alrasheed and Fatima

RSA Attacks. By Abdulaziz Alrasheed and Fatima RSA Attacks By Abdulaziz Alrasheed and Fatima 1 Introduction Invented by Ron Rivest, Adi Shamir, and Len Adleman [1], the RSA cryptosystem was first revealed in the August 1977 issue of Scientific American.

More information

Embedding more security in digital signature system by using combination of public key cryptography and secret sharing scheme

Embedding more security in digital signature system by using combination of public key cryptography and secret sharing scheme International Journal of Computer Sciences and Engineering Open Access Research Paper Volume-4, Issue-3 E-ISSN: 2347-2693 Embedding more security in digital signature system by using combination of public

More information

Information & Communication Security (SS 15)

Information & Communication Security (SS 15) Information & Communication Security (SS 15) Electronic Signatures Dr. Jetzabel Serna-Olvera @sernaolverajm Chair of Mobile Business & Multilateral Security Goethe University Frankfurt www.m-chair.de Agenda

More information

Archived NIST Technical Series Publication

Archived NIST Technical Series Publication 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

More information

Computer Science 308-547A Cryptography and Data Security. Claude Crépeau

Computer Science 308-547A Cryptography and Data Security. Claude Crépeau Computer Science 308-547A Cryptography and Data Security Claude Crépeau These notes are, largely, transcriptions by Anton Stiglic of class notes from the former course Cryptography and Data Security (308-647A)

More information

Analysis of Software Realized DSA Algorithm for Digital Signature

Analysis of Software Realized DSA Algorithm for Digital Signature ELECTRONICS, VOL. 15, NO. 2, DECEMBER 2011 73 Analysis of Software Realized DSA Algorithm for Digital Signature Bojan R. Pajčin and Predrag N. Ivaniš Abstract In this paper the realization of one algorithm

More information

Network Security. Chapter 2 Basics 2.2 Public Key Cryptography. Public Key Cryptography. Public Key Cryptography

Network Security. Chapter 2 Basics 2.2 Public Key Cryptography. Public Key Cryptography. Public Key Cryptography Chair for Network Architectures and Services Department of Informatics TU München Prof. Carle Encryption/Decryption using Public Key Cryptography Network Security Chapter 2 Basics 2.2 Public Key Cryptography

More information

Software Tool for Implementing RSA Algorithm

Software Tool for Implementing RSA Algorithm Software Tool for Implementing RSA Algorithm Adriana Borodzhieva, Plamen Manoilov Rousse University Angel Kanchev, Rousse, Bulgaria Abstract: RSA is one of the most-common used algorithms for public-key

More information

Public Key Cryptography. c Eli Biham - March 30, 2011 258 Public Key Cryptography

Public Key Cryptography. c Eli Biham - March 30, 2011 258 Public Key Cryptography Public Key Cryptography c Eli Biham - March 30, 2011 258 Public Key Cryptography Key Exchange All the ciphers mentioned previously require keys known a-priori to all the users, before they can encrypt

More information

Tool. For. University Of Hyderabad

Tool. For. University Of Hyderabad Tool. For Signing & Verification Submitted To: Submitted By: Shri Patrick Kishore Chief Operating Officer Sujit Kumar Tiwari MCA, I Year University Of Hyderabad Certificate by Guide This is certifying

More information

www.studymafia.org Seminar report Digital Signature Submitted in partial fulfillment of the requirement for the award of degree Of Computer Science

www.studymafia.org Seminar report Digital Signature Submitted in partial fulfillment of the requirement for the award of degree Of Computer Science A Seminar report on Digital Signature Submitted in partial fulfillment of the requirement for the award of degree Of Computer Science SUBMITTED TO: www.studymafia.org SUBMITTED BY: www.studymafia.org Preface

More information

CERTIFICATE AUTHORITY SCHEMES USING ELLIPTIC CURVE CRYPTOGRAPHY, RSA AND THEIR VARIANTS- SIMULATION USING NS2

CERTIFICATE AUTHORITY SCHEMES USING ELLIPTIC CURVE CRYPTOGRAPHY, RSA AND THEIR VARIANTS- SIMULATION USING NS2 American Journal of Applied Sciences 11 (2): 171-179, 2014 ISSN: 1546-9239 2014 Science Publication doi:10.3844/ajassp.2014.171.179 Published Online 11 (2) 2014 (http://www.thescipub.com/ajas.toc) CERTIFICATE

More information

SEC 4: Elliptic Curve Qu-Vanstone Implicit Certificate Scheme (ECQV)

SEC 4: Elliptic Curve Qu-Vanstone Implicit Certificate Scheme (ECQV) Standards for Efficient Cryptography SEC 4: Elliptic Curve Qu-Vanstone Implicit Certificate Scheme (ECQV) Contact: Certicom Research Eoin Buckley (mbuckley@blackberry.com) April 3, 2014 Version (Draft)

More information

NISTIR 7676 Maintaining and Using Key History on Personal Identity Verification (PIV) Cards

NISTIR 7676 Maintaining and Using Key History on Personal Identity Verification (PIV) Cards NISTIR 7676 Maintaining and Using Key History on Personal Identity Verification (PIV) Cards David A. Cooper NISTIR 7676 Maintaining and Using Key History on Personal Identity Verification (PIV) Cards David

More information

National Security Agency Perspective on Key Management

National Security Agency Perspective on Key Management National Security Agency Perspective on Key Management IEEE Key Management Summit 5 May 2010 Petrina Gillman Information Assurance (IA) Infrastructure Development & Operations Technical Director National

More information

Cryptography. some history. modern secret key cryptography. public key cryptography. cryptography in practice

Cryptography. some history. modern secret key cryptography. public key cryptography. cryptography in practice Cryptography some history Caesar cipher, rot13 substitution ciphers, etc. Enigma (Turing) modern secret key cryptography DES, AES public key cryptography RSA, digital signatures cryptography in practice

More information

Applied Cryptography Public Key Algorithms

Applied Cryptography Public Key Algorithms Applied Cryptography Public Key Algorithms Sape J. Mullender Huygens Systems Research Laboratory Universiteit Twente Enschede 1 Public Key Cryptography Independently invented by Whitfield Diffie & Martin

More information

Message Authentication

Message Authentication Message Authentication message authentication is concerned with: protecting the integrity of a message validating identity of originator non-repudiation of origin (dispute resolution) will consider the

More information

Cryptographic Algorithms and Key Size Issues. Çetin Kaya Koç Oregon State University, Professor http://islab.oregonstate.edu/koc koc@ece.orst.

Cryptographic Algorithms and Key Size Issues. Çetin Kaya Koç Oregon State University, Professor http://islab.oregonstate.edu/koc koc@ece.orst. Cryptographic Algorithms and Key Size Issues Çetin Kaya Koç Oregon State University, Professor http://islab.oregonstate.edu/koc koc@ece.orst.edu Overview Cryptanalysis Challenge Encryption: DES AES Message

More information

Recommendation for Applications Using Approved Hash Algorithms

Recommendation for Applications Using Approved Hash Algorithms NIST Special Publication 800-107 Revision 1 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

More information

Digital signatures. Informal properties

Digital signatures. Informal properties Digital signatures Informal properties Definition. A digital signature is a number dependent on some secret known only to the signer and, additionally, on the content of the message being signed Property.

More information

Efficient construction of vote-tags to allow open objection to the tally in electronic elections

Efficient construction of vote-tags to allow open objection to the tally in electronic elections Information Processing Letters 75 (2000) 211 215 Efficient construction of vote-tags to allow open objection to the tally in electronic elections Andreu Riera a,,joseprifà b, Joan Borrell b a isoco, Intelligent

More information

Crittografia e sicurezza delle reti. Digital signatures- DSA

Crittografia e sicurezza delle reti. Digital signatures- DSA Crittografia e sicurezza delle reti Digital signatures- DSA Signatures vs. MACs Suppose parties A and B share the secret key K. Then M, MAC K (M) convinces A that indeed M originated with B. But in case

More information

Public Key Cryptography and RSA. Review: Number Theory Basics

Public Key Cryptography and RSA. Review: Number Theory Basics Public Key Cryptography and RSA Murat Kantarcioglu Based on Prof. Ninghui Li s Slides Review: Number Theory Basics Definition An integer n > 1 is called a prime number if its positive divisors are 1 and

More information

Data Encryption A B C D E F G H I J K L M N O P Q R S T U V W X Y Z. we would encrypt the string IDESOFMARCH as follows:

Data Encryption A B C D E F G H I J K L M N O P Q R S T U V W X Y Z. we would encrypt the string IDESOFMARCH as follows: Data Encryption Encryption refers to the coding of information in order to keep it secret. Encryption is accomplished by transforming the string of characters comprising the information to produce a new

More information

Symmetric Mechanisms for Authentication in IDRP

Symmetric Mechanisms for Authentication in IDRP WG1/SG2 WP WG2/WP 488 International Civil Aviation Organization Aeronautical Telecommunication Network Panel (ATNP) WG2 and WG1/SG2 Meetings Honolulu, Hawaii, USA January 1999 Symmetric Mechanisms for

More information

Table of Contents. Bibliografische Informationen http://d-nb.info/996514864. digitalisiert durch

Table of Contents. Bibliografische Informationen http://d-nb.info/996514864. digitalisiert durch 1 Introduction to Cryptography and Data Security 1 1.1 Overview of Cryptology (and This Book) 2 1.2 Symmetric Cryptography 4 1.2.1 Basics 4 1.2.2 Simple Symmetric Encryption: The Substitution Cipher...

More information

IT Networks & Security CERT Luncheon Series: Cryptography

IT Networks & Security CERT Luncheon Series: Cryptography IT Networks & Security CERT Luncheon Series: Cryptography Presented by Addam Schroll, IT Security & Privacy Analyst 1 Outline History Terms & Definitions Symmetric and Asymmetric Algorithms Hashing PKI

More information

Application of Digital Signature for Securing Communication Using RSA Scheme based on MD5

Application of Digital Signature for Securing Communication Using RSA Scheme based on MD5 Application of Digital Signature for Securing Communication Using RSA Scheme based on MD5 Fashoto S.G, Gbadeyan J.A and Okeyinka E.A Redeemer s University, Redemption camp Mowe, Ogun State gbengafash@yahoo.com

More information