WorksheetsSection 3 - Cryptography and encryption
Total questions: 85
Worksheet time: 43mins
What is the definition of Plaintext?
An Unencrypted Message
A type of encryption algorithm
A compressed file format
A digital signature
What is the definition of Ciphertext?
An Encrypted Message
A Secret Key
A Plaintext Message
A Decryption Algorithm
What is the definition of Cipher?
The Process (Algorithm) Used to Encrypt and Decrypt a Message
A Device Used to Store Data
A Type of Network Protocol
A Programming Language
What is the definition of Cryptanalysis?
The Art of Cracking Cryptographic Systems
The Study of Ancient Scripts
The Process of Encrypting Data
The Design of Secure Networks
Which of the following is NOT a main type of cryptographic algorithm?
Hashing Algorithms
Symmetric Encryption Cipher
Asymmetric Encryption Cipher
Data Compression Algorithm
What does a Hashing Algorithm produce from an input plaintext?
A fixed length string
A random sequence of numbers
An encrypted message
A variable length output
What is a hashing collision?
A hashing collision occurs when two different plain texts produce the exact same hash value.
A hashing collision occurs when a hash function produces only unique outputs.
A hashing collision occurs when a hash value can be reversed to obtain the original plain text.
A hashing collision occurs when a hash function is used for encryption.
What does the Secure Hash Algorithm (SHA) produce?
A 256-Bit Digest
A 512-Bit Encryption Key
A Plain Text Message
A 128-Bit Symmetric Key
What does the Message Direct Algorithm #5 (MD5) produce?
A 128-Bit Digest
A 256-Bit Digest
A 64-Bit Digest
A 512-Bit Digest
What is a Birthday Attack in the context of hashing algorithms?
A brute force attack aimed at exploiting collisions in hash functions, which could be used for forging a digital signature.
An attack that targets the encryption key by guessing it directly.
A method of intercepting messages during transmission to alter their content.
A technique used to increase the speed of hash function computations.
What is an encryption algorithm?
A type of cryptographic process that encodes data so that it can be recovered or decrypted.
A programming language used for web development.
A hardware device that stores passwords.
A method for compressing image files.
The cipher text “uryyb jbeyq” means what in plain text?
hello world
good night
open sesame
secret code
In contrast to substitution ciphers, what stays the same in a transposition cipher but their order is changed according to some mechanism?
The units in a transposition cipher stay the same in plain text and cipher text but their order is changed.
The key used for encryption remains unchanged.
The length of the ciphertext is always doubled.
The frequency of each letter is altered.
What is symmetric encryption?
Symmetric encryption is where both encryption and decryption are performed by the same secret key and can be used for confidentiality.
Symmetric encryption uses two different keys for encryption and decryption.
Symmetric encryption is only used for digital signatures.
Symmetric encryption does not provide confidentiality.
Refer to the diagram showing Alice and Bob exchanging files. What key do Alice and Bob share to encrypt and decrypt the file?
A symmetric key.
A public key.
A hash key.
A session token.
There are two types of ciphers: Stream ciphers and block ciphers. Which of the following statements is true about stream ciphers?
The plaintext is divided into equal-size blocks
Each byte or bit of data is encrypted one at a time
The plaintext is padded to the correct size
Encryption and decryption are performed by different keys
Block cipher: The plaintext is divided into equal-size blocks (usually 128-bit). If there is not enough data in the plaintext, it is padded to the correct size.
True
False
What is the main difference between symmetric and asymmetric encryption?
Symmetric encryption uses the same secret key for both encryption and decryption, while asymmetric encryption uses two different but related public and private keys.
Symmetric encryption uses two unrelated keys, while asymmetric encryption uses the same key for both processes.
Symmetric encryption is only used for digital signatures, while asymmetric encryption is only used for data storage.
Symmetric encryption is slower and more secure than asymmetric encryption.
In asymmetric encryption, each key is capable of reversing the operation of its pair and they are linked in such a way as to make it impossible to derive one from the other.
True
False
Who generates the asymmetric key pair and keeps the private key secret in the process of asymmetric encryption?
Alice
Bob
Mallory
None of the above
What does Alice use to encrypt her message in asymmetric encryption?
Her own private key
Bob's public key
Bob's private key
Mallory's public key
Fill in the blank: After Alice encrypts the message, she sends the ________ to Bob.
ciphertext
plaintext
key
signature
Bob decrypts the ciphertext using his private key.
True
False
Can Mallory use Bob's public key to reverse the encryption and obtain the original message?
Yes
No
What is the major drawback of asymmetric encryption mentioned in the worksheet?
It involves substantial computing resources.
It is not secure for data transmission.
It cannot be used for digital signatures.
It is only suitable for small files.
Asymmetric encryption is mostly used for which of the following?
Data compression
Authentication and Non-Repudiation
Image processing
File storage
Who published the RSA cipher in 1977?
Ron Rivest, Adi Shamir, and Leonard Adleman
Whitfield Diffie and Martin Hellman
Claude Shannon
Phil Zimmermann
What is a mode of operation in cryptography? Fill in the blank: A mode of operation is a means of using a cipher within a product to achieve a security goal such as ________ or ________.
confidentiality, integrity
speed, efficiency
compression, expansion
authentication, repudiation
Which of the following is used to authenticate a sender while hashing can prove integrity?
Symmetric Key Cryptography
Public Key Cryptography
Digital Certificates
Cipher Suite
Fill in the blank: Both public key cryptography and hashing can be combined to authenticate a sender and prove the integrity of a message. This usage is called a ________.
digital signature
encryption tunnel
hash chain
public certificate
Which type of encryption can encrypt and decrypt large amounts of data but is difficult to distribute the secret key securely?
Symmetric encryption
Asymmetric encryption
Digital Certificates
Cipher Suite
Asymmetric (PKC) encryption can distribute the key easily but cannot be used for large amounts of data.
True
False
What is the role of a certificate authority (CA) in public key infrastructure? Fill in the blank: A certificate authority can validate the owner of the public key by issuing the subject with a ________.
certificate
password
token
private key
Which of the following is NOT a component of a cipher suite?
Signature Algorithm
Key Exchange/Agreement Algorithm
Digital Signature
Bulk Encryption Symmetric Key
What is the function of a Signature Algorithm in a cipher suite? Fill in the blank: A Signature Algorithm is used to assert the identity of the server’s public key and facilitate ________.
authentication
encryption
compression
routing
What is a cryptographic primitive?
A) A type of computer virus
B) A single hash function, symmetric or asymmetric cipher
C) A programming language
D) A type of network protocol
Fill in the blank: Authentication & non-repudiation depend on the recipient not being able to ______ the message or impersonate the sender.
encrypt
decrypt
forward
delete
Which of the following is supported by cryptography to ensure that even if cipher text is stolen, the threat actor cannot understand or change what has been stolen?
Authentication
Confidentiality
Obfuscation
Repudiation
Integrity in cryptography is proved by:
Encryption algorithms
Hashing algorithms
Compression algorithms
Sorting algorithms
What is the art of making a message difficult to understand, as mentioned in the passage?
Obfuscation
Clarification
Translation
Simplification
Fill in the blank: ______ refers to the measure of confidence that people have in a given cipher and how long data must be kept secure.
Longevity
Redundancy
Bandwidth
Latency
Fill in the blank: ______ is when passwords stored as hashes are vulnerable to brute force and dictionary attacks, and attackers generate hashes to try and find a match for the captured password hash.
Salting
Encryption
Tokenization
Compression
Fill in the blank: ______ is a technique that takes a key generated from a user password plus a random salt value and repeatedly converts it to a longer and more random key, making brute force attacks slower.
Key Stretching
Hash Collisions
Public Key Encryption
Digital Signing
Fill in the blank: ______ is the conversion of data into cipher text that can be analyzed and worked with as if it were still in its original form, enabling complex mathematical operations on encrypted data without compromising the encryption.
Homomorphic Encryption
Symmetric Encryption
Hashing
Steganography
Fill in the blank: ______ is a concept in which an expanding list of transactional records is secured using cryptography, with each record referred to as a block and linked cryptographically.
Blockchain
Hash Table
Data Mining
Cloud Storage
Fill in the blank: ______ is a technique for obscuring the presence of a message, such as hiding a message in a picture, where the container document or file is called the cover text.
Steganography
Cryptography
Watermarking
Compression
What is the purpose of giving someone your public key when you want them to send you confidential messages?
To allow them to decrypt your messages
To allow them to encrypt messages for you
To sign documents
To verify your identity
When you want to authenticate yourself to others, what do you use to sign the message?
Your public key
Their private key
Your private key
Their public key
Fill in the blank: A ________ is the entity responsible for issuing and guaranteeing certificates.
Certificate Authority
Certificate User
Certificate Generator
Certificate Holder
Which PKI trust model involves a single CA issuing certificates to users, and if the CA is compromised, the entire PKI collapses?
Hierarchical (Intermediate CA)
Single CA
Distributed CA
Mesh CA
In the Hierarchical (Intermediate CA) trust model, what is the role of the root CA?
The root CA issues certificates to several intermediate CAs, which then issue certificates to subjects (leaf or end entities).
The root CA directly issues certificates to all end users without any intermediaries.
The root CA only verifies the identity of end users and does not issue any certificates.
The root CA acts as a backup server for intermediate CAs in case of failure.
What is an online CA?
A CA that is disconnected from any network
A CA that is available to accept and process certificate signing requests and management tasks
A CA that only updates intermediate CAs
A CA that never signs certificates
Fill in the blank: A secure configuration will involve making the root CA an ______ CA, meaning it is disconnected from any network and only brought back online to add or update intermediate CAs.
off-line
online
public
shared
What is the process by which end users create an account with the CA and become authorized to request certificates called?
Registration
Validation
Signing
Encryption
When a subject wants to obtain a certificate, what does it complete and submit to the CA?
Certificate Signing Request (CSR)
Certificate Revocation List (CRL)
Public Key Infrastructure (PKI)
Online Certificate Status Protocol (OCSP)
After receiving a Certificate Signing Request (CSR) from a subject, the CA:
Issues the certificate after verifying the request
Ignores the request
Sends the request back to the subject
Deletes the request without action
What is a Digital Certificate?
A Digital Certificate is essentially a wrapper for a subject’s public key. It contains information about the subject and the certificate’s issuer.
A Digital Certificate is a physical card used to access secure buildings.
A Digital Certificate is a type of software used to encrypt files on a computer.
A Digital Certificate is a password used to log into secure websites.
What does the 'Serial number' field in a digital certificate represent?
A number uniquely identifying the certificate within the domain of its CA.
The expiration date of the certificate.
The public key of the certificate holder.
The name of the issuing authority.
What is the purpose of the 'Signature algorithm' field in a digital certificate?
The algorithm used by the CA to sign the certificate.
The algorithm used to encrypt the certificate data.
The algorithm used to generate the public key.
The algorithm used to verify the user's identity.
What information does the 'Issuer' field in a digital certificate provide?
The name of the CA.
The public key of the user.
The expiration date of the certificate.
The serial number of the certificate.
What does the 'Valid from/to' field indicate in a digital certificate?
Date and time during which the certificate is valid.
The name of the certificate authority.
The encryption algorithm used.
The public key of the certificate holder.
What does the 'Subject' field in a digital certificate contain?
The name of the certificate holder, expressed as a distinguished name (DN). The common name (CN) part should usually match either the fully qualified domain name (FQDN) of the server or a user email address.
The issuing authority's public key information.
The expiration date of the certificate.
A list of all trusted root certificates.
What is stored in the 'Public key' field of a digital certificate?
Public key and algorithm used by the certificate holder.
Private key of the certificate holder.
Digital signature of the certificate authority.
Certificate expiration date.
What can be defined in the 'Extensions' field of a digital certificate?
V3 certificates can be defined with extended attributes, such as friendly subject or issuer names, contact email addresses, and intended key usage.
The Extensions field is used to store the private key of the certificate.
Extensions field contains the certificate's expiration date only.
Extensions field is used to encrypt the entire certificate.
What is the purpose of the 'Subject alternative name (SAN)' field in a digital certificate?
This extension field is the preferred mechanism to identify the DNS name or names by which a host is identified.
It specifies the encryption algorithm used by the certificate.
It contains the private key associated with the certificate.
It defines the expiration date of the certificate.
A wildcard domain such as *.comptia.org means that the certificate issued to the parent domain will be accepted as valid for all subdomains.
True
False
Fill in the blank: The EKU field can have the following value: ______ Authentication.
Server
User
Device
Fill in the blank: The EKU field can have the following value: ______ Authentication.
Client
Server
User
Device
Fill in the blank: The EKU field can have the following value: ______ Signing.
Code
Document
Network
Fill in the blank: The EKU field can have the following value: Email ______.
Protection
Encryption
Signature
Authentication
Which type of web server certificate proves the ownership of a particular domain?
Domain Validation (DV)
Extended Validation (EV)
Machine Certificate
Root Certificate
Which type of web server certificate requires more rigorous checks on the subject’s legal identity and control over the domain?
Domain Validation (DV)
Extended Validation (EV)
Self-Signed Certificate
Email Certificate
Fill in the blank: Other certificate types include ______/Computer Certificates.
Machine
User
Network
Device
Fill in the blank: Other certificate types include Email/______ Certificates.
User
Server
Device
Network
Fill in the blank: Other certificate types include ______ Signing Certificates.
Code
Document
Network
Fill in the blank: Other certificate types include ______ Certificates, which are not signed by a trusted authority.
Self-Signed
Wildcard
Root Authority
Extended Validation
Which of the following is NOT a stage in the Key Life Cycle?
Key Generation
Certificate Generation
Storage
Encryption Only
Fill in the blank: The process of making a key invalid before its expiration is called ______.
Revocation
Delegation
Encryption
Replication
Fill in the blank: The process of updating a key after its validity period is called Expiration and ______.
Renewal
Revocation
Deletion
Suspension
What does 'Escrow' mean in terms of key management?
Escrow means that something is held independently which in terms of key management, means a third party is trusted to store the key securely.
Escrow means the key is destroyed after use and cannot be recovered.
Escrow means the key is only stored on the user's device and never shared.
Escrow means the key is publicly available for anyone to use.
When renewing a certificate, what is it called when you use the existing key?
Key renewal
Key rotation
Key revocation
Key escrow
When renewing a certificate, what is it called when you generate a new key?
Rekeyed
Revoked
Reissued
Resigned
Which of the following is NOT a reason for certificate revocation or suspension?
Key Compromise
Ca Compromise
Certificate Hold
Superseded
A suspended key is given which code?
Certificate Hold
Key Revoked
Key Active
Key Expired
A certificate may be revoked or suspended due to which of the following reasons?
Key compromise and change in user status
Certificate expiration and renewal
User training completion and promotion
System upgrade and software update
