Cryptography and Hashing Algorithms
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Questions and Answers

What is the hash value in bits for MD5?

  • 128 (correct)
  • 160
  • 512
  • 256

    • In IPSec Tunnel mode, what type of encryption is provided?

  • End-to-end encryption
  • Gateway-to-gateway encryption (correct)
  • Host-to-network encryption
  • Point-to-point encryption

    • What is a weakness of one-way hashing without additional measures?

  • It produces the same output for the same input. (correct)
  • It increases computational time significantly.
  • It cannot handle large inputs.
  • It creates varied outputs for the same input.

    • What key size should be minimally used with RC4?

    <p>40 bits</p> Signup and view all the answers

    Which algorithm has a block size of 64 bits and a key size of 56 bits?

    <p>DES</p> Signup and view all the answers

    What does a rainbow table consist of?

    <p>Precomputed hash values for passwords</p> Signup and view all the answers

    What is the maximum key size for RC4?

    <p>2048 bits</p> Signup and view all the answers

    Which key should be shared in asymmetric cryptography to facilitate decryption?

    <p>Public key</p> Signup and view all the answers

    Which options refer to the modes used in symmetric encryption to process blocks of data?

    <p>Block cipher modes</p> Signup and view all the answers

    Which symmetric block cipher modes allow operation similar to a stream cipher?

    <p>CFB, OFB, CTR</p> Signup and view all the answers

    Symmetric block ciphers perform substitution using which method?

    <p>S-boxes</p> Signup and view all the answers

    What is the block size in bits for the PRESENT cipher?

    <p>64</p> Signup and view all the answers

    Which type of cryptography uses a pair of keys for encryption and decryption?

    <p>Asymmetric</p> Signup and view all the answers

    Which key is necessary to facilitate symmetric encryption decryption?

    <p>Secret key</p> Signup and view all the answers

    What is the maximum key size for the RC5 symmetric block cipher?

    <p>2048</p> Signup and view all the answers

    What key size and IV does the Rabbit cipher operate with?

    <p>128 bit keys; 64 bit IV</p> Signup and view all the answers

    Which is a known public key encryption method that protects against adaptive chosen ciphertext attacks?

    <p>Cramer-Shoup</p> Signup and view all the answers

    Which encoding scheme supports Base64 and ASCII formats for x.509 certificates?

    <p>PEM</p> Signup and view all the answers

    What allows for generating a unique passcode for each instance based on a time period?

    <p>Timed One Time Password (TOTP)</p> Signup and view all the answers

    Which key method is utilized to create a tunnel in SSL/TLS?

    <p>Symmetric key method</p> Signup and view all the answers

    What unit is used to measure computational work within Ethereum applications?

    <p>Gas</p> Signup and view all the answers

    Which cipher is designed specifically for hardware implementations and uses variable parameters?

    <p>SIMON</p> Signup and view all the answers

    Which asymmetric key is used to sign a digitally signed message?

    <p>Shawn's private key</p> Signup and view all the answers

    Which of the following best describes a system where an attacker reuses sent messages at a later time?

    <p>Replay attack</p> Signup and view all the answers

    In the context of certificate management, which stage involves certificate expiration and revocation?

    <p>Cancellation</p> Signup and view all the answers

    What cryptographic method uses a direct relationship between parts of known plaintext and ciphertext?

    <p>Known plaintext attack</p> Signup and view all the answers

    What term describes a method where it is possible mathematically for government agents to access encrypted information?

    <p>NOBUS</p> Signup and view all the answers

    What is the protocol number for the encapsulation security protocol (ESP)?

    <p>50</p> Signup and view all the answers

    Which type of hash solution do Buzhash, Cityhash, and Spookyhash represent?

    <p>Non-cryptographic</p> Signup and view all the answers

    What type of contracts automate execution and do not require intermediaries?

    <p>Smart contracts</p> Signup and view all the answers

    Which attack method involves mixing parts of two encrypted messages to form a new message?

    <p>Cut-and-paste attack</p> Signup and view all the answers

    What component is crucial for the ID management and lifecycle of digital certificates?

    <p>Certificate authority (CA)</p> Signup and view all the answers

    What is the key difference between a revoked status and a hold status in certificate lifecycle?

    <p>Hold status is temporary; revoked status is permanent.</p> Signup and view all the answers

    Which of the following best describes the elliptic curve used in RFID implementations?

    <p>A light-weight solution</p> Signup and view all the answers

    What protocol is used for key exchange in the IPSec handshake?

    <p>UDP port 500</p> Signup and view all the answers

    Which cipher employs a grid that maps letters into numeric values?

    <p>Bifid</p> Signup and view all the answers

    What block size is utilized by AES?

    <p>128 bits</p> Signup and view all the answers

    Which encryption standard is referred to as PKCS #5?

    <p>Password-based encryption</p> Signup and view all the answers

    What does the 'birthday attack' refer to in probability theory?

    <p>Hash collisions</p> Signup and view all the answers

    Which method supports symmetric key exchange in elliptic curve cryptography?

    <p>ECDH</p> Signup and view all the answers

    Which cipher is known as a shift cipher that replaces letters down the alphabet?

    <p>Caesar</p> Signup and view all the answers

    Which block cipher mode is susceptible to copy-and-paste attacks?

    <p>ECB</p> Signup and view all the answers

    In symmetric cryptography, which process is faster for real-time communication?

    <p>Symmetric cryptography</p> Signup and view all the answers

    What is measured by entropy in the context of encryption?

    <p>Unpredictability</p> Signup and view all the answers

    Which initialization vector (IV) size does WPA use for TKIP?

    <p>48 bits</p> Signup and view all the answers

    What type of encryption does the Paillier cryptosystem support?

    <p>Homomorphic encryption</p> Signup and view all the answers

    Which cipher utilizes a two-dimensional array to encode characters?

    <p>Four-square</p> Signup and view all the answers

    Which key size is used for AES when operating with 14 rounds?

    <p>256 bits</p> Signup and view all the answers

    What key size is standard for 3DES encryption?

    <p>112 bits</p> Signup and view all the answers

    What type of cipher is used by Blowfish?

    <p>Symmetric block cipher</p> Signup and view all the answers

    Which of these hashing algorithms is considered a lightweight algorithm?

    <p>PHOTON</p> Signup and view all the answers

    What is the key size of the Skipjack cipher?

    <p>80 bits</p> Signup and view all the answers

    What critical step does a certificate authority take after generating a digital certificate?

    <p>Sign the certificate with the CA's own private key</p> Signup and view all the answers

    Which algorithm is known for operating with asymmetric keys in key exchange?

    <p>Diffie-Hellman</p> Signup and view all the answers

    What type of encoding supports up to 65,536 characters?

    <p>UTF-16</p> Signup and view all the answers

    Which cipher is characterized by having a variable key size up to 2048 bits and block sizes of 32, 64, or 128 bits?

    <p>RC5</p> Signup and view all the answers

    What is the recommended minimum key size for RC2 encryption?

    <p>40 bits</p> Signup and view all the answers

    Which statement correctly defines a mono-alphabetic substitution?

    <p>Employs a single mapping of the entire alphabet</p> Signup and view all the answers

    ChaCha is classified as which type of algorithm?

    <p>Symmetric stream cipher</p> Signup and view all the answers

    What is the primary purpose of HMAC?

    <p>Authenticate messages and verify integrity</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the One-time pad?

    <p>Uses a key multiple times</p> Signup and view all the answers

    What does WEP use for its RC4 encryption?

    <p>40 bits</p> Signup and view all the answers

    IDEA ciphers have how many rounds of substitution and transposition?

    <blockquote> <p>17 rounds</p> </blockquote> Signup and view all the answers

    Study Notes

    Hashing Algorithms

    • MD5 hash value in bits: 128
    • SHA-1 hash value in bits: 160
    • MD4 hash value in bits: 128
    • Hashing takes a variable-length input and produces a fixed-length output (message digest).

    IPSec Modes

    • IPSec Transport mode: End-to-end encryption; data encrypted from sender's device to receiver's device.
    • IPSec Tunnel mode: Encryption from gateway to gateway; only through the public network space. Encryption occurs just before leaving the local network. Traffic between user device and local network boundary is likely unencrypted

    Chaskey

    • Lightweight cryptography method for signing messages (MAC).
    • Suitable for IoT implementation due to low hardware requirements.
    • Key size: 128 bits

    One-Way Hashing Weakness

    • Applying salt prevents the same plaintext from resulting in the same ciphertext.

    RC4

    • Symmetric stream cipher with variable key size up to 2048 bits.
    • Minimum recommended key size: 40 bits.

    Data Encryption Standard (DES)

    • Block size: 64 bits
    • Key size: 56 bits
    • 16 rounds of substitution & transposition.

    Rainbow Table

    • Collection of precomputed hash values of actual plaintext passwords used for password cracking

    x.509 Certificate File Types

    • .cer is a common x.509 certificate file type used with PEM and DER formats

    Triple Data Encryption Standard (3DES)

    • Block size: 64 bits
    • Key size: 112 bits
    • 48 rounds of substitution & transposition.

    Advanced Encryption Standard (AES)

    • Key sizes: 128, 192, or 256 bits
    • Operates using 128-bit blocks

    Skipjack

    • Symmetric block cipher
    • Key size: 80 bits
    • Block size: 64 bits

    Enocoro

    • Key size: 128 bits
    • Initialization vector (IV): 64 bits

    Light-weight Hashing Algorithms

    • Examples Include PHOTON, SPONGENT, Lesamnta-LW, and Quark

    IDEA

    • Block size: 64 bits
    • Key size: 128 bits
    • More than 17 rounds of substitution & transposition

    RSA

    • Partially homomorphic crypto system
    • Uses prime number characteristics
    • Variable key size (1024-4096 bits)
    • 1 round

    Blowfish and Twofish

    • Symmetric block ciphers
    • Common key sizes include 128, 192, or 256 bits.

    RC5

    • Symmetric block cipher with variable key size up to 2048 bits.
    • Uses block sizes of 32, 64, or 128 bits

    Quark

    • Hash value: 64 or 112 bits

    XTEA

    • Block size: 64 bits
    • Key size: 128 bits

    Camelia

    • Symmetric block cipher

    RC6

    • Symmetric block cipher

    RC2

    • Block size: 64 bits
    • Variable key size up to 128 bits
    • Minimum recommended key size: 40 bits

    Mickey v2

    • Key size: 80 bits
    • Initialization vector (IV): Up to 80 bits

    ChaCha

    • Symmetric stream cipher

    RSA and DSA

    • Asymmetric algorithms

    Diffie-Hellman

    • Provides a method for key exchange using a one-way function

    WEP

    • Uses 40-bit RC4

    WPA

    • Uses 128-bit RC4

    WPA2

    • Uses AES

    Mono-alphabetic and polyalphabetic Substitution Ciphers

    • Mono-alphabetic: Single mapping from our alphabet to a cipher alphabet.
    • Polyalphabetic: Mapping to a number of cipher alphabets.

    One-time Pad

    • Considered unbreakable due to its one-time use of cipher code

    Encoding Methods

    • ASCII: 8-bit values, supports up to 256 characters.
    • UTF-16: 16-bit values, supports up to 65,536 characters.

    Collision

    • Occurs when two different inputs produce the same hash signature.

    Hardware Security Modules (HSMs)

    • Tamper-evident and intrusion-resistant devices.
    • Safeguard and manage cryptographic keys.
    • Provide cryptographic processing.

    Trusted Platform Modules (TPMs)

    • Dedicated processors for hardware-level encryption.
    • Allow full disk encryption with minimal performance impact.

    HMAC

    • Message authentication code (MAC).
    • Verifies message integrity and authentication by hashing the message with a secret key.

    Binary Operations

    • XOR: Example calculation provided.
    • AND: Example calculation provided.
    • OR: Example calculation provided.

    Modular Arithmetic

    • Example mod calculations provided.

    Cipher Types

    • Symmetric: Single secret key for encryption/decryption.
    • Asymmetric: Key pair (public/private) for encryption/decryption.

    Block Cipher Modes

    • Block cipher modes manage how data blocks are processed in symmetric encryption
    • CFB, OFB, CTR block cipher modes allow block cipher to operate like a stream cipher.

    Symmetric Block Ciphers

    • Use S-boxes for substitution during encryption.

    Cryptographic Keys

    • Public key: Shared or distributed for decryption in asymmetric cryptography.
    • Secret key: Exchanged for decryption in symmetric cryptography

    Block and Key Sizes (Examples):

    • CLEFIA: 128-bit blocks, 128, 192, or 256-bit keys
    • Rabbit: 128-bit keys, 64-bit IV
    • PRESENT: 64-bit block size, 80 or 128-bit keys

    Certificate Management Stages:

    • Initialization: Certificate distribution
    • Issued: Certificate retrieval/recovery and validation
    • Cancellation: Certificate expiration and revocation

    Certificate Authority (CA) and Certificate Revocation List (CRL)

    • CA publishes CRL.
    • CRL: Lists revoked certificates.

    Online Certificate Status Protocol (OCSP)

    • Online service for checking certificate validity.

    Certificate Revoked Status vs. Hold Status

    • Revoked: Cannot be reversed
    • Hold: Reversible

    Cryptographic Attacks

    • Exhaustive search: Brute-force attack trying every possible key.
    • Man-in-the-middle (MITM): Attacker impersonates both parties.
    • Known plaintext attack: Intruder knows part of the ciphertext and corresponding plaintext.
    • Time attack: Determining decryption time to find the key.
    • Replay attack: Sending a legitimate message at a later time.
    • Cut-and-paste attack: Mixing parts of different encrypted messages.

    Cryptographic Backdoors

    • Key escrow and NOBUS create backdoors in cryptography.

    Blockchain

    • Ledger of transactions for Bitcoin and other networks.
    • Miners compile transaction lists.
    • Miners receive rewards for successful mining efforts.
    • Smart contracts automate agreements.
    • Ethereum Gas: Unit to measure work for hashing.

    Early Ciphers

    • Caesar, Bifid, Playfair, Pigpen, Vigenere, and Four-square cipher are described as example ciphers.

    AES Block and Key Sizes

    • AES block size: 128 bits
    • AES key sizes: 128, 192, or 256 bits

    Block Cipher Modes (Examples)

    • Output Feedback (OFB) encrypts IV and uses the result.
    • Cipher Feedback (CFB) XORs data with encrypted IV.
    • Counter Mode (CTR) enables parallel data block processing

    Cryptographic Concepts (Examples)

    • ECDH: Elliptic Curve Diffie-Hellman (key exchange).
    • Paillier: Homomorphic encryption.
    • PKCS #5/7: Password-based encryption and signing/encrypting messages Standards.
    • Entropy: Measure of unpredictability in encryption.
    • Digital certificate: Proves server identity in HTTPS.
    • Public key: Found in digital certificates.
    • WPA 48-bit Initialization Vector(IV) value.

    Other

    • LM Hash: Stores user passwords in some version of Windows (max 15 characters).
    • Birthday Attack: Probability theory used in brute-force attacks in cryptography.
    • TSP (Time-Stamp Protocol): Provides cryptographically-verified timestamps.
    • El Gamal: Public key method for encryption and digital signing.
    • Identity-based Encryption (IBE): Generating encryption keys from recipient identity information.
    • RC4: Symmetric stream cipher used in SSL.
    • Cipher Feedback (CFB): XORs data with encrypted IV.
    • Counter Mode (CTR): Parallel data block processing.
    • Unicode: Used in some security implementations.

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    Description

    This quiz covers key concepts of cryptographic techniques, including hashing algorithms like MD5 and SHA-1, as well as IPSec modes and the Chaskey method. You will also explore the weaknesses of one-way hashing and the specifications of symmetric stream ciphers like RC4. Test your knowledge on these critical aspects of modern security architecture.

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