Data Security and Encryption Flashcard

Front

What is the fundamental difference between encryption and authentication in the context of data security?

Back

Encryption ensures data confidentiality by coding it, while authentication verifies the legitimacy of a transaction or user.

Answer explanation

The correct choice highlights that encryption focuses on ensuring data confidentiality through coding, while authentication is about verifying the legitimacy of users or transactions, which is essential for data security.

Front

Explain the core characteristic of symmetric encryption algorithms and provide two examples mentioned in the text.

Back

Symmetric encryption uses a secret key known by both sender and receiver for both encryption and decryption; examples include Caesar Cipher and AES.

Front

How does encryption contribute to the security of data stored or transmitted? Briefly describe one way it achieves this.

Back

Encryption keeps data safe by 'abstracting' it, making it unreadable without the correct key.

Front

Describe the basic principle behind the Caesar cipher encryption method, including the role of the 'key shift'.

Back

The Caesar cipher encrypts a message by shifting each letter in the plaintext by a specific number of positions down the alphabet, determined by the 'key shift'.

Answer explanation

The correct choice explains that the Caesar cipher encrypts a message by shifting each letter in the plaintext by a specific number of positions down the alphabet, which is defined by the 'key shift'. This simple method is effective for basic encryption.

Front

What does the term 'mod 26' signify in the context of the Caesar cipher algorithm?

Back

'Mod 26' ensures that the shifted letter stays within the 26 letters of the English alphabet by calculating the remainder after division by 26.

Answer explanation

'Mod 26' is crucial in the Caesar cipher as it keeps the shifted letters within the 26 letters of the English alphabet by using the remainder after division by 26, ensuring valid letter outputs.

Front

Besides security, what other practical benefit of encryption is mentioned in the text, particularly in relation to images?

Back

Encryption has practical compression benefits with images as a means of storing the image data in a very efficient way keeping the file size down.

Answer explanation

The correct choice highlights that encryption provides practical compression benefits for images, allowing for efficient storage of image data while reducing file size, which is crucial for transmission and storage.

Front

Explain what the 'brute-force approach' entails when trying to decipher a message encrypted with a Caesar cipher.

Back

The 'brute-force approach' to deciphering a Caesar cipher involves trying all 25 possible key shifts until the message becomes readable.

Answer explanation

The 'brute-force approach' for a Caesar cipher involves systematically trying all 25 possible shifts of the alphabet until the original message is revealed, making it a straightforward method for decryption.

Front

How can 'letter frequency analysis' be used to decrypt a Caesar cipher without knowing the key?

Back

Letter frequency analysis exploits the fact that certain letters appear more frequently in a language (like E, T, A, O in English). By identifying the most frequent letter in the ciphertext, it can be inferred that it likely represents the most frequent letter in the original plaintext (and thus the key shift).

Answer explanation

Letter frequency analysis is effective because certain letters, like E and T, occur more frequently in English. By finding the most common letter in the ciphertext, Anika and Aiden can deduce its likely plaintext equivalent, revealing the key shift.

Front

According to the text, why is it important for both the sender and receiver to know the secret key in symmetric encryption?

Back

In symmetric encryption, the same secret key is used for both encryption and decryption, so both the sender needs it to encrypt the message, and the receiver needs it to decrypt and read the original message.

Answer explanation

In symmetric encryption, both the sender and receiver must know the same secret key because it is used for both encrypting and decrypting the message. This ensures that the sender can encrypt the data and the receiver can decrypt it to read the original message.

Front

What is meant by 'abstraction' in the context of data security through encryption?

Back

Abstraction in encryption is the process of taking away or removing characteristics from the data to reduce it to essential characteristics, making the original data unreadable or hidden in a secure form.

Answer explanation

'Abstraction' in encryption means removing characteristics from data to make it unreadable or hidden, focusing on essential traits. This process secures the original data, aligning with the correct choice.