General security Concepts Part 1

Which statement best describes symmetric encryption?

• Uses the same key for encryption and decryption

• Uses a public key to encrypt data and a private key to decrypt it

• Encrypts data one bit at a time with no key

• Automatically rotates keys for every message

Answer explanation

Symmetric encryption relies on a shared secret key for both encryption and decryption, making it fast and efficient for bulk data.

What is the main challenge of symmetric encryption?

• Cipher complexity

• High computational load

• Compatibility with digital signatures

• Key distribution

Answer explanation

The difficulty lies in securely sharing the secret key between sender and receiver without interception.

How does asymmetric encryption solve the key distribution problem?

• By sharing the private key publicly

• By using a shared secret for both parties

• By using a public key to encrypt and a private key to decrypt

• By encrypting only hashes, not the message

Answer explanation

Asymmetric encryption allows the public key to be shared freely, while the private key remains secret, solving key distribution challenges.

In hybrid encryption, what role does asymmetric encryption play?

• Encrypts all bulk data

• Creates digital signatures only

• Exchanges a symmetric session key securely

• Hashes the message before encryption

Answer explanation

Asymmetric encryption is used to securely transmit the symmetric session key, which then encrypts the actual data.

What is a key property of a secure hash function?

• Encryption reversibility

• Collision resistance

• Use of a shared secret key

• Ability to decrypt data

Answer explanation

A secure hash function is collision-resistant, meaning it is highly unlikely that two different inputs will produce the same hash value.

Why is salting used in password hashing?

• To make passwords unreadable by adding a random string

• To encrypt the password with a public key

• To reduce hash computation time

• To allow symmetric decryption

Answer explanation

Salting adds a unique random string to each password, making precomputed rainbow table attacks ineffective.

What does a digital signature ensure?

• Only confidentiality of the message

• Authentication, integrity, and non-repudiation

• Faster encryption of bulk data

• Public key distribution

Answer explanation

Digital signatures prove the sender’s identity, ensure the message wasn’t altered, and prevent the sender from denying it.

Which component of PKI verifies the identity of a certificate requester?

• End-Entity

• Certificate Repository

• Registration Authority (RA)

• Root Certificate

Answer explanation

The RA assists the Certificate Authority (CA) in validating the requester’s identity before issuing a certificate.

What feature of blockchain ensures that data cannot be altered once added?

• Proof of Work

• Hash chaining

• Tokenization

• Encryption with AES

Answer explanation

Each block contains a hash of the previous block, creating an immutable chain.

Which obfuscation technique replaces sensitive data with meaningless tokens?

• Data masking

• Tokenization

• De-Identification

• Anonymization

Answer explanation

Tokenization substitutes sensitive data with tokens that have no intrinsic value, protecting the original data.