Month: November 2022

Data Integrity in Cryptography

Until now, we discussed the use of symmetric and public key schemes to achieve the confidentiality of information. With this chapter, we begin our discussion on different cryptographic techniques designed to provide other security services. The focus of this chapter is on data integrity and cryptographic tools used to achieve the same. Threats to Data… Continue reading Data Integrity in Cryptography

ElGamal Analysis

In ElGamal system, each user has a private key x. and has three components of public key − prime modulus p, generator g, and public Y = gx mod p. The strength of the ElGamal is based on the difficulty of discrete logarithm problem. The secure key size is generally > 1024 bits. Today even 2048 bits long key… Continue reading ElGamal Analysis

Example

An example of generating RSA Key pair is given below. (For ease of understanding, the primes p & q taken here are small values. Practically, these values are very high). de = 29 × 5 = 145 = 1 mod 72 Encryption and Decryption Once the key pair has been generated, the process of encryption… Continue reading Example

RSA Analysis

The security of RSA depends on the strengths of two separate functions. The RSA cryptosystem is most popular public-key cryptosystem strength of which is based on the practical difficulty of factoring the very large numbers. If either of these two functions are proved non one-way, then RSA will be broken. In fact, if a technique… Continue reading RSA Analysis

RSA Cryptosystem

This cryptosystem is one the initial system. It remains most employed cryptosystem even today. The system was invented by three scholars Ron Rivest, Adi Shamir, and Len Adleman and hence, it is termed as RSA cryptosystem. We will see two aspects of the RSA cryptosystem, firstly generation of key pair and secondly encryption-decryption algorithms. Generation of RSA Key Pair… Continue reading RSA Cryptosystem

Public Key Encryption

Public Key Cryptography Unlike symmetric key cryptography, we do not find historical use of public-key cryptography. It is a relatively new concept. Symmetric cryptography was well suited for organizations such as governments, military, and big financial corporations were involved in the classified communication. With the spread of more unsecure computer networks in last few decades,… Continue reading Public Key Encryption

Counter (CTR) Mode

It can be considered as a counter-based version of CFB mode without the feedback. In this mode, both the sender and receiver need to access to a reliable counter, which computes a new shared value each time a ciphertext block is exchanged. This shared counter is not necessarily a secret value, but challenge is that… Continue reading Counter (CTR) Mode