Cryptography

5 minutes 5 Questions

Cryptography is a technique used to secure and protect data from unauthorized access and tampering. It involves encryption and decryption processes, which converts data into unreadable formats (cipher-text) and back to the original format (plain-text) respectively. Cryptography can protect data in transit or at rest, and includes symmetric key encryption, asymmetric key encryption, as well as different hashing algorithms for data integrity. In addition to encryption, cryptography is also used for digital signatures, authentication, and ensuring data confidentiality and integrity.

Guide: Understanding & Answering Questions on Cryptography for CompTIA A+ Security

Cryptography is a fundamental concept within CompTIA A+ Security.

Why is it important?
Cryptography is the science of securing information by converting it into an unreadable format. It's essential for protecting sensitive data from unauthorized access, ensuring both data integrity and confidentiality in digital communications.

What is it?
Cryptography uses algorithms and ciphers to encrypt and decrypt data. The encrypted data (ciphertext) can only be read if decrypted back to its original form (plaintext) by someone who possesses the correct decryption key.

How does it work?
Cryptography involves the use of encryption keys. These keys, used within mathematical algorithms, transform plain data into encrypted data. In symmetric-key cryptography, the same key is used for encryption and decryption. In asymmetric-key cryptography, different keys (public and private) are used for encryption and decryption.

Exam Tips: Answering Questions on Cryptography
When answering questions, ensure you understand the difference between symmetric and asymmetric cryptography, and the concept of cryptographic keys. Familiarize yourself with common cryptographic algorithms such as RSA, AES, and DES. Remember, in exam scenarios, encryption is used primarily to protect confidentiality of data. It's also crucial to make sure you understand hashing, digital signatures, and public key infrastructure (PKI).

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Question 1

A security consultant is asked to review the cryptographic configurations used during data transmission between two offices. The configuration mentions using AES with a 128-bit key for symmetric encryption and RSA with a 2048-bit key for key exchange. Which type of encryption system is in use?

Quantum encryption Asymmetric encryption Symmetric encryption Hybrid encryption

Correct Answer: Hybrid encryption

Hybrid encryption uses a combination of both symmetric and asymmetric encryption algorithms. In this case, AES with a symmetric key is used for data encryption, and RSA with an asymmetric key is being used to securely exchange those keys, making this a hybrid encryption system.

Question 2

A large organization receives a suspicious email claiming to come from the CEO, but the message fails email authentication measures. What cryptographic mechanism can the organization implement to better determine whether the sender is legitimate in the future?

Message encryption Key exchange One-time pad Digital signature

Correct Answer: Digital signature

Digital signatures can be used to authenticate the sender's identity and ensure the message integrity, thus confirming the authenticity of the email sender. Message encryption and key exchanges don't provide sender authentication. One-time pads and hashing are not directly applicable to the scenario, and two-factor authentication is more related to access control.

Question 3

An organization discovers that the symmetric keys used for secure file transfers were not dropped from memory after usage, leading to potential key exposure. What key management best practice was not followed?

Key escrow Key rotation Key generation Key destruction

Correct Answer: Key destruction

Key destruction is the process of securely removing keys from memory after usage, preventing unauthorized access to the keys. Not destroying the keys after use violates a key management best practice. The other options, like key generation, rotation, escrow, isolation, and substitution, are not related to removing keys from memory.

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