Consider the following Encrypted Key Exchange (EKE) protocol where A and B share a common password P, Ep denotes a symmetric key encryption algorithm using P as the encryption key, and Encpx denotes a public key encryption algorithm using PK as the encryption key. Note that PK is randomly generated by A in each session. Ep (РК) Ep (Eпсрк (К)) 1. A → B : 2. В — А: Output : K (Session key). (1) Is this protocol secure if we replace the ephemeral PK in step 1 by a digital certificate (i.e., a PK certified by a trusted CA)? Justify your answer. (2) Does this protocol provide forward secrecy? Justify your answer.

Consider the following Encrypted Key Exchange (EKE) protocol where A and B share a common password P, Ep denotes a symmetric key encryption algorithm using P as the encryption key, and Encpx denotes a public key encryption algorithm using PK as the encryption key. Note that PK is randomly generated by A in each session. Ep (РК) Ep (Eпсрк (К)) 1. A → B : 2. В — А: Output : K (Session key). (1) Is this protocol secure if we replace the ephemeral PK in step 1 by a digital certificate (i.e., a PK certified by a trusted CA)? Justify your answer. (2) Does this protocol provide forward secrecy? Justify your answer.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Concept explainers

Hash Table

A hash table also called a hash map, is a data structure that maps key-value pairs. The hash table can be used in complex systems to provide fast access and compact storage. A hash table is a structure that stores data in an abstract data type kind of associative array. It keeps data in an array format, with a distinct index value for every data value. If the index of the required data is known, then the data can be accessed very easily.

Question

Consider the following Encrypted Key Exchange (EKE) protocol where A and B share a common password P, Ep denotes a symmetric key encryption algorithm using P as the encryption
key, and Encpk denotes a public key encryption algorithm using PK as the encryption key. Note that PK is randomly generated by A in each session.
В:
Ep (РК)
Ep(Епсрк (К))
1. A
2.
В
» A:
Output : K (Session key).
(1) Is this protocol secure if we replace the ephemeral PK in step 1 by a digital certificate (i.e., a PK certified by a trusted CA)? Justify your answer.
(2) Does this protocol provide forward secrecy? Justify your answer.

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