Asymmetric encryption (RSA) in Computer Networks - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

How RSA Uses Two Keys

In RSA encryption, what is the main purpose of having a public key and a private key?

A Both keys are used only for encrypting messages, not decrypting.

B Both keys encrypt and decrypt messages interchangeably without restrictions.

C The public key encrypts messages, and only the private key can decrypt them.

D The private key encrypts messages, and the public key decrypts them.

💡 Hint

Think about who should be able to read the message after encryption.

In RSA, the public key is shared openly to encrypt messages. Only the private key, kept secret, can decrypt those messages, ensuring security.

📋 Factual

intermediate

Key Components of RSA

Which two mathematical components are essential in generating RSA keys?

A Two large prime numbers

B Two random integers

C Two even numbers

D Two Fibonacci numbers

💡 Hint

These numbers must be special and hard to factor.

RSA keys are generated using two large prime numbers. Their product forms part of the public key, and their properties ensure security.

🔍 Analysis

advanced

Why RSA Encryption is Secure

Why is it difficult for someone to break RSA encryption without the private key?

A Because the keys change every second automatically.

B Because factoring the product of two large primes is very hard.

C Because the encryption uses simple addition and subtraction.

D Because the private key is shared publicly.

💡 Hint

Focus on the math problem behind the encryption.

The security of RSA relies on the difficulty of factoring a very large number made by multiplying two large primes. Without factoring, the private key cannot be found easily.

❓ Comparison

advanced

Difference Between Symmetric and Asymmetric Encryption

Which statement correctly compares symmetric encryption with RSA asymmetric encryption?

A Symmetric uses one key for both encrypting and decrypting; RSA uses two different keys.

B Symmetric encryption is slower than RSA encryption.

C RSA uses the same key for encryption and decryption, symmetric uses two keys.

D Both symmetric and RSA use two keys but for different purposes.

💡 Hint

Think about how many keys each method uses and their roles.

Symmetric encryption uses a single shared key for both encrypting and decrypting. RSA uses a pair of keys: one public for encrypting and one private for decrypting.

❓ Reasoning

expert

Understanding RSA Key Length Impact

What is the main effect of increasing the key length in RSA encryption?

A It makes encryption faster but reduces security.

B It makes decryption impossible even with the private key.

C It has no effect on security or speed.

D It makes encryption and decryption slower but increases security.

💡 Hint

Longer keys mean more work for computers but better protection.

Longer RSA keys increase the difficulty of breaking the encryption, improving security. However, they require more computing power, slowing down encryption and decryption.