Untitled Quiz

<p>The attacker cannot infer past or future keystream values. (D)</p> Signup and view all the answers

<p>It controls how the state machine transitions between states. (B)</p> Signup and view all the answers

<p>To enforce the confidentiality of information (B)</p> Signup and view all the answers

<p>By applying a cipher with a key (A)</p> Signup and view all the answers

<p>They require the same key for both encryption and decryption. (D)</p> Signup and view all the answers

<p>The key used for encryption (C)</p> Signup and view all the answers

<p>Brute force attack (D)</p> Signup and view all the answers

<p>Key (D)</p> Signup and view all the answers

<p>Steganography (B)</p> Signup and view all the answers

<p>It needs key distribution to all parties. (D)</p> Signup and view all the answers

<p>Symmetric encryption with the same key (D)</p> Signup and view all the answers

<p>They transform each fixed-length block of bits. (C)</p> Signup and view all the answers

<p>Employs multiple substitution alphabets based on the symbol. (C)</p> Signup and view all the answers

<p>To obscure the relationship between the key, plaintext, and ciphertext. (B)</p> Signup and view all the answers

<p>Symmetric stream ciphers (A)</p> Signup and view all the answers

<p>To provide randomness for encrypting the plaintext. (C)</p> Signup and view all the answers

<p>Typically offers better performance. (A)</p> Signup and view all the answers

<p>A stream cipher that can be perfectly secure. (C)</p> Signup and view all the answers

<p>Symmetric uses the same key for both encryption and decryption, asymmetric uses a key pair. (C)</p> Signup and view all the answers

<p>Vernam cipher (or one-time pad) (D)</p> Signup and view all the answers

<p>Clever attacks (A)</p> Signup and view all the answers

<p>It is constant across encryption operations. (A)</p> Signup and view all the answers

<p>To ensure a change in one plaintext bit affects the entire ciphertext unpredictably (D)</p> Signup and view all the answers

<p>They can produce ciphertext blocks longer than plaintext blocks. (A)</p> Signup and view all the answers

<p>RC4 (B)</p> Signup and view all the answers

The art and science of hidden writing, initially focused on securing information confidentiality.

The art and science of breaking cryptographic systems or encrypted information.

The combination of cryptography and cryptanalysis.

A specific cryptographic technique used to encrypt or decrypt information.

A parameter in a cipher algorithm that influences its execution and allows for encryption and decryption.

Original, unencrypted information.

Encrypted information, appearing as a random sequence of symbols.

An exhaustive search method used to find the key by trying all possible combinations.

Uses the same key for encryption and decryption.

The art of concealing data, unlike cryptography, which only protects data by masking it.

The set of all possible keys of a given size.

Each key has an equal chance of being the correct one, making attacks harder.

Methods to reduce the possible keys, identifying patterns.

Systems for substituting symbols in a sequence, usually of the same length.

One substitution alphabet used for all symbols in the encryption/decryption process.

Using several substitution alphabets, one for each symbol to hide patterns.

Ciphers that operate on a bit-by-bit encryption or decryption by XORing with a keystream.

A stream of random or pseudo-random bits used with stream ciphers.

Perfect cipher using truly random keystream; rarely used due to key management.

Processing data in blocks of bits, often bytes, resulting in transformations.

Use the same key for encryption and decryption.

Use different keys for encryption and decryption.

Complex relationship between key, plaintext, and ciphertext in a cipher

Dispersing plaintext statistics to ciphertext, creating the avalanche effect.

A type of symmetric encryption that encrypts data bit by bit using a pseudo-random keystream generated by a pseudo-random bit generator (PRBG).

A cryptographic algorithm that generates a sequence of bits that appear random but is actually deterministic, meaning it's predictable if the starting point and rules are known.

A unique value used to initialize the state of the PRBG for each message. It ensures that even with the same key, different messages produce different keystreams.

The secret input of the PRBG, specifying how the state machine producing the keystream updates.

The pseudo-random bit sequence generated by the PRBG used to encrypt/decrypt messages.

The basic math operation used in stream ciphers to combine the plaintext with the keystream.

Using the same key and IV for two messages causes the encryption of those messages to use the same keystream, allowing an attacker to potentially derive one message from another if they know the other.

A cryptanalytic attack where the attacker chooses specific plaintext messages with the intent to decrypt them using particular methods for the purposes of gaining greater information about the key or algorithm.