Block Ciphers – IT Exams

Analyzing the TLS record, Exams of IT, GHASH function, IT Certification, Plaintext integrity, Security of generic composition, TLS Record protocol

CTR mode – Block Ciphers and Their Modes of Operation

08/31/202408/31/2024

Posted by Whitney Koehler

14.4.5 CTR mode The Counter (CTR) mode, illustrated in Figure 14.12, is a mode of operation that applies the underlying block cipher f to generate a key stream that is subsequently used for

XTS mode – Block Ciphers and Their Modes of Operation

06/05/202408/31/2024

Posted by Whitney Koehler

14.4.6 XTS mode The Tweakable Block Cipher with Ciphertext Stealing (XTS), shown in Figure 14.14, is a mode of operation designed to ensure confidentiality of data stored on block devices, that is,

Block ciphers in TLS 1.3 – Block Ciphers and Their Modes of Operation

04/15/202408/31/2024

Posted by Whitney Koehler

14.5 Block ciphers in TLS 1.3 In TLS, block ciphers are used for protecting the confidentiality and integrity of data transmitted over the TLS Record layer. More precisely, a block cipher is used for

Preliminaries – Authenticated Encryption

03/20/202408/31/2024

Posted by Whitney Koehler

15.1 Preliminaries Before diving into the details of authenticated encryption, we must first introduce some security concepts that we will need later on for an in-depth understanding and comparison

Indistinguishability under a chosen-ciphertext attack 3 – Authenticated Encryption

01/20/202408/31/2024

Posted by Whitney Koehler

It is easy to show that even given a probabilistic public-key encryption scheme like the one defined above – that is, a scheme offering semantic security against any polynomial time adversary –

Indistinguishability under a chosen-ciphertext attack 2 – Authenticated Encryption

01/19/202408/31/2024

Posted by Whitney Koehler

To get an intuitive understanding of why the above definition is useful for cryptographic purposes, let’s look at a simple example taken from . Assume that Alice, Bob, and a trusted third party

Indistinguishability under a chosen-ciphertext attack – Authenticated Encryption

01/18/202408/31/2024

Posted by Whitney Koehler

15.1.2 Indistinguishability under a chosen-ciphertext attack Chosen-Ciphertext Attack (CCA) is a more powerful attack than a chosen-plaintext attack. Recall that in a chosen-plaintext attack Eve is

Plaintext integrity – Authenticated Encryption

11/11/202308/31/2024

Posted by Whitney Koehler

15.1.4 Plaintext integrity In terms of the integrity of symmetric encryption schemes, the notion of plaintext integrity requires an encryption scheme to be designed in such a way that no algorithm

Authenticated encryption – generic composition – Authenticated Encryption

09/30/202308/31/2024

Posted by Whitney Koehler

15.2 Authenticated encryption – generic composition An authenticated encryption (AE) scheme is a symmetric-key encryption scheme that provides both confidentiality as well as message integrity and

MAC-then-encrypt – generic composition – Authenticated Encryption

07/11/202308/31/2024

Posted by Whitney Koehler

15.2.2 MAC-then-encrypt The MAC-then-encrypt composition computes the MAC of the plaintext m, appends the MAC to the plaintext, and encrypts the resulting value: The MAC-then-encrypt composition is