COEN 351 Non-Repudiation. A non-repudiation service provides assurance of the origin or delivery of data in order to protect the sender against false.

Slides:

Advertisements

Similar presentations

Chapter 10 Encryption: A Matter of Trust. Awad –Electronic Commerce 1/e © 2002 Prentice Hall 2 OBJECTIVES What is Encryption? Basic Cryptographic Algorithm.

Advertisements

Public Key Infrastructure A Quick Look Inside PKI Technology Investigation Center 3/27/2002.

A New Approach of Signing Documents with Symmetric Cryptosystems and an Arbitrator Nol Premasathian Faculty of Science King Mongkut’s.

PROJECT ON DIGITAL SIGNATURE Submitted by: Submitted to: NAME: Roll no: Reg.no. :

Cryptography and Network Security

Tracing Computer Forensics 152 / 252.

Cryptography and Network Security Chapter 13 Fourth Edition by William Stallings Lecture slides by Lawrie Brown.

Cryptography and Network Security Chapter 13 Fourth Edition by William Stallings.

1 Digital Signatures & Authentication Protocols. 2 Digital Signatures have looked at message authentication –but does not address issues of lack of trust.

1 Chapter 13 – Digital Signatures & Authentication Protocols Fourth Edition by William Stallings Lecture slides by Lawrie Brown (modified by Prof. M. Singhal,

Authentication Cristian Solano. Cryptography is the science of using mathematics to encrypt and decrypt data. Public Key Cryptography –Problems with key.

Lecture 5: security: PGP Anish Arora CSE 5473 Introduction to Network Security.

COEN 350 Security. Contents Why? How to forge ? How to spot spoofed . Distribution Lists The twist that makes authentication … interesting.

6/1/20151 Digital Signature and Public Key Infrastructure Course:COSC Instructor:Professor Anvari Student ID: Name:Xin Wen Date:11/25/00.

Department of Information Engineering1 Major Concerns in Electronic Commerce Authentication –there must be proof of identity of the parties in an electronic.

6/4/2015National Digital Certification Agency1 Security Engineering and PKI Applications in Modern Enterprises Mohamed HAMDI National.

Lecture III : Communication Security, Services & Mechanisms Internet Security: Principles & Practices John K. Zao, PhD SMIEEE National Chiao-Tung University.

Cryptography Basic (cont)

Spring 2002CS 4611 Security Outline Encryption Algorithms Authentication Protocols Message Integrity Protocols Key Distribution Firewalls.

8-1 What is network security? Confidentiality: only sender, intended receiver should “understand” message contents m sender encrypts message m receiver.

Cryptography and Network Security Third Edition by William Stallings Lecture slides by Lawrie Brown.

Presented by Xiaoping Yu Cryptography and PKI Cosc 513 Operating System Presentation Presented to Dr. Mort Anvari.

1 Intro To Encryption Exercise Analyze the following scenario: Sender:  Cipher1= Encrypt message with symmetric key algorithm  RSA_Encrypt (SHA1(message)

Information Security of Embedded Systems : Algorithms and Measures Prof. Dr. Holger Schlingloff Institut für Informatik und Fraunhofer FIRST.

Elias M. Awad Third Edition ELECTRONIC COMMERCE From Vision to Fulfillment 13-1© 2007 Prentice-Hall, Inc ELC 200 Day 23.

Security Jonathan Calazan December 12, 2005.

TrustPort Public Key Infrastructure. Keep It Secure Table of contents  Security of electronic communications  Using asymmetric cryptography.

E- Business Digital Signature Varna Free University Prof. Teodora Bakardjieva.

Pay As You Go – Associating Costs with Jini Leases By: Peer Hasselmeyer and Markus Schumacher Presented By: Nathan Balon.

1. INDEX 2 A signature is a handwritten depiction of someone’s name or nickname that a person writes on documents as proof of identity and intent. Signature.

Digital Signature Xiaoyan Guo/ Xiaohang Luo/

INTRODUCTION Why Signatures? A uthenticates who created a document Adds formality and finality In many cases, required by law or rule Digital Signatures.

COEN 351 Non-Repudiation. A non-repudiation service provides assurance of the origin or delivery of data in order to protect the sender against false.

Security using Encryption Security Features Message Origin Authentication - verifying that the sender is who he or she says they are Content Integrity.

1 Lecture 18: Security issues specific to security key management services –privacy –integrity/authentication –nonrepudiation/plausible deniability.

Tracing Examples Computer Forensics Tracing Examples.

Non-repudiation Robin Burke ECT 582. Midterm scores Ave: 69 Std. dev: 23 Median: 75 Max: 100 Min: 35.

Secure Data Transmission EDI-INT AS1, AS2, AS3 Kevin Grant.

Information Security Principles Assistant Professor Dr. Sana’a Wafa Al-Sayegh 1 st Semester ITGD 2202 University of Palestine.

Chapter 14 Encryption: A Matter Of Trust. Awad –Electronic Commerce 2/e © 2004 Pearson Prentice Hall 2 OBJECTIVES What is Encryption? Basic Cryptographic.

03/09/05Oregon State University X-Sig: An Signing Extension for the Simple Mail Transport Protocol (SMTP) Robert Rose 03/09/05.

AQA Computing A2 © Nelson Thornes 2009 Section Unit 3 Section 6.4: Internet Security Digital Signatures and Certificates.

Public-key Cryptography Strengths and Weaknesses Matt Blumenthal.

SSL / TLS in ITDS Arun Vishwanathan 23 rd Dec 2003.

E-Commerce Security Professor: Morteza Anvari Student: Xiaoli Li Student ID: March 10, 2001.

Chapter 6 Electronic Mail Security MSc. NGUYEN CAO DAT Dr. TRAN VAN HOAI 1.

Certificate-Based Operations. Module Objectives By the end of this module participants will be able to: Define how cryptography is used to secure information.

Key Management. Session and Interchange Keys  Key management – distribution of cryptographic keys, mechanisms used to bind an identity to a key, and.

23-1 Last time □ P2P □ Security ♦ Intro ♦ Principles of cryptography.

Cryptography and Network Security Chapter 13 Fourth Edition by William Stallings.

 A Web service is a method of communication between two electronic devices over World Wide Web.

Cryptography and Network Security Chapter 13 Fourth Edition by William Stallings Lecture slides by Lawrie Brown & Süleyman KONDAKCI.

Lecture 16: Security CDK4: Chapter 7 CDK5: Chapter 11 TvS: Chapter 9.

Tracing Computer Forensics 252  Thomas Schwarz, S.J

Identity Proofing, Signatures, & Encryption in Direct esMD Author of Record Workgroup John Hall Coordinator, Direct Project June 13, 2012.

DIGITAL SIGNATURE.

1 of 4 This document is for informational purposes only. MICROSOFT MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS DOCUMENT. © 2006 Microsoft Corporation.

Fall 2006CS 395: Computer Security1 Key Management.

Copyright 2004 MayneStay Consulting Group Ltd. - All Rights Reserved Jan-041 Security using Encryption Security Features Message Origin Authentication.

April 20023CSG11 Electronic Commerce Authentication John Wordsworth Department of Computer Science The University of Reading Room.

Content Introduction History What is Digital Signature Why Digital Signature Basic Requirements How the Technology Works Approaches.

Fourth Edition by William Stallings Lecture slides by Lawrie Brown

 Introduction  History  What is Digital Signature  Why Digital Signature  Basic Requirements  How the Technology Works  Approaches.

Chapter 5a - Pretty Good Privacy (PGP)

Unit 3 Section 6.4: Internet Security

S/MIME T ANANDHAN.

CDK4: Chapter 7 CDK5: Chapter 11 TvS: Chapter 9

CDK: Chapter 7 TvS: Chapter 9

Digital Signatures Network Security.

Presentation transcript:

COEN 351 Non-Repudiation

A non-repudiation service provides assurance of the origin or delivery of data in order to protect the sender against false denial by the recipient that the data has been received, or to protect the recipient against false denial by the sender that the data has been sent. Thus, a non- repudiation service provides evidence to prevent a person from unilaterally modifying or terminating legal obligations arising out of a transaction effected by computer-based means. American Bar Association

Non-Repudiation Legal Need: Enough evidence to meet the legal requirement for proof that signature / communication occured. Not exactly equivalent to the cryptography standard.

Non-Repudiation Traditional written signature delivered by mail Can be forged. But forging is difficult. Name under Easily forged. Digitally signed Almost impossible to forge Needs key theft Successful crypto-attack on verified and trusted scheme.

Non-Repudiation Non-repudiation of origin Non-repudiation of submission Non-repudiation of delivery

Non-Repudiation Non-repudiation request Parties need to agree on non-repudiation services. Record generation Record distribution Record verification Record retention

Non-Repudiation of Origin Originator’s Digital Signature Message Hash of Message encrypted with private key. Certificate by trusted party containing public key. Key-Revocation: Time of key revocation is crucial, hence time of message.

Non-Repudiation of Origin Transactional Certificate Only used for one transaction. Message Hash of message, encrypted by private key of originator. Signature of trusted party on originator signature

Non-Repudiation of Origin Inline trusted third party (Evidence stored) Originator sends message to trusted third party. Trusted third party stores evidence of transaction (signed message digest, time stamp) Trusted third party forwards message.

Non-Repudiation of Origin Inline trusted third party (Evidence forwarded) Originator sends message to trusted third party. Trusted third party signs message (signed message digest + time stamp) Trusted third party forwards message with signature.

Non-Repudiation of Delivery Recipient Acknowledgment with Signature Recipient signs digest of received message and sends it back to the sender. “Reluctant recipient problem”

Non-Repudiation of Delivery Trusted Delivery Agent Akin to process server Police officer, deputy delivering summons or subpoena. Delivery agent is trusted when attesting to handing message to recipient Delivery agent signs digest of message and returns it to sender after handing it to the receiver.

Non-Repudiation of Delivery Progressive Delivery Reports Mail transfer protocol hands messages from one mail server to the next. Possible to send reports from each mail server. header has a record of those hand-offs

Protocols: SMTP To: From: This is a spoofed message. From Tue Dec 23 17:25: Return-Path: Received: from Xavier (dhcp engr.scu.edu [ ]) by server4.engr.scu.edu ( / ) with ESMTP id hBO1Plpv for ; Tue, 23 Dec :25: Received: from mail pickup service by Xavier with Microsoft SMTPSVC; Tue, 23 Dec :25: To: From: Message-ID: X-OriginalArrivalTime: 24 Dec :25: (UTC) FILETIME=[D3B56160:01C3C9 BC] Date: 23 Dec :25: X-Spam-Checker-Version: SpamAssassin 2.60-rc3 ( exp) on server4.engr.scu.edu X-Spam-Level: X-Spam-Status: No, hits=0.3 required=5.0 tests=NO_REAL_NAME autolearn=no version=2.60-rc3 This is a spoofed message.

Non-Repudiation of Submission Messages are handled by a delivery system Not under control of sender Reasonably efficient in sending messages Delivery system can send receipt to sender.

Non-Repudiation Trusted Third Party Role Public-key certification Identity and authority validation By (co)signing Time stamping service Records retention Delivery intermediation Dispute resolution