A developer encrypts data using the same key for both encryption and decryption. What type of encryption is being used?

A bank wants secure communication between branches using a key pair (public/private). Which algorithm is most suitable?

A laptop uses a block cipher to encrypt entire disks. Which symmetric algorithm is most appropriate?

A legacy system still uses DES but is concerned about brute-force attacks. What is DES’s main weakness?

A security engineer must choose a secure AES key size for financial data. What should they select?

A company wants to authenticate files downloaded from their website to ensure they were not changed. Which method should they use?

A system admin uses hashing for passwords. They need a secure hashing algorithm. Which one?

A database needs extra protection from rainbow table attacks. What should the admin apply to stored hashes?

A company encrypts data using public key cryptography. Which key should remain secret?

A sender wants to encrypt a message so only the receiver can decrypt it. Which key should be used for encryption?

An organization needs to securely exchange keys over an insecure network. What protocol should they use?

A company notices that their encrypted image files still show visible patterns. Which mode is likely used incorrectly?

A system requires confidentiality and integrity during encryption. What mode of AES should be used?

A developer needs a fast symmetric algorithm for bulk file encryption. Which is best?

A web application uses digital signatures to verify software updates. What security property does this provide?

A certificate is being verified before a secure connection is established. What entity issued this certificate?

A mobile app requires strong encryption but limited processing power. Which algorithm is ideal?

A cloud storage service encrypts all user files with a key derived from the user’s password. What technique strengthens weak passwords?

A developer needs to encrypt streaming data in real time. Which cipher type is best?

An attacker tries every possible key to crack encrypted data. What attack is this?

A security team needs to protect encryption keys in case employees lose them. Which method is used?

A system generates a unique digital certificate request. What is this file called?

A message encrypted with the sender’s private key is meant to provide what?

A government agency wants an algorithm with strong resistance to brute-force attacks due to large key sizes. Which fits?

A network administrator needs to know whether a public key still belongs to an active user. What list should they check?

A website wants to ensure secure browsing for users. Which protocol must be enabled?

A researcher detects two different files producing the same hash value. What is this called?

A developer needs to encrypt small chunks of data repeatedly and quickly. What algorithm is ideal?

A secure email application uses asymmetric encryption. Which key do users share publicly?

A network device needs to exchange secret keys securely before using symmetric encryption. Which algorithm does this?

A developer notices that decrypting data requires the same key used for encryption. What encryption type is it?

A company wants to ensure that encrypted data cannot be decrypted even if keys are stolen later. What technique achieves this?

A wireless network uses a lightweight stream cipher for fast data encryption. Which algorithm is likely used?

A security engineer wants to protect message integrity while also authenticating the sender. What should be used?

An administrator encrypts backups using AES in CBC mode. What else must be securely stored with the ciphertext?

A user wants to send encrypted data but does not want anyone to know the message exists. What method hides the data?

A messaging app uses a technique where each session uses a unique encryption key. What is this principle?

Which of the following is the correct answer?

An attacker intercepts a key exchange but cannot compute the shared key because of mathematical difficulty. Which protocol is protecting them?

A security audit shows that encryption relies on the difficulty of factoring large prime numbers. What type of cryptography is used?