M2: Cryptographic building blocks - C2 Flashcards
What is encryption?
Turning readable data into a secret code to keep it safe.
What is decryption?
Turning the secret code back into readable data.
What is symmetric-key encryption?
Using the same key to both encrypt and decrypt data.
What is public-key encryption?
Using a public key to encrypt data and a private key to decrypt it.
What is a digital signature?
A unique tag added to a message to verify the sender’s identity.
What is a cryptographic hash function?
A function that converts data into a fixed-size string of characters which appears random.
What is message authentication?
Ensuring that a message comes from a legitimate source and hasn’t been altered.
What is authenticated encryption?
Combining encryption and authentication to protect data confidentiality and integrity.
What is a certificate?
A digital document that verifies the ownership of a public key.
What is the Vernam cipher?
An encryption method using a key as long as the message known for being unbreakable if used correctly.
What is a one-time pad?
A type of Vernam cipher where the key is used only once and is as long as the message.
What is a block cipher?
An encryption method that processes data in fixed-size blocks.
What is a stream cipher?
An encryption method that processes data one bit or byte at a time.
What is the Advanced Encryption Standard (AES)?
A widely used block cipher for securing data.
What is the Caesar cipher?
An ancient encryption technique that shifts letters by a fixed number of places.
What is exhaustive key search?
Trying all possible keys until the correct one is found.
What is a passive adversary?
An attacker who only observes and records data without altering it.
What is an active adversary?
An attacker who can alter data or inject new data into the communication.
What is a known-plaintext attack?
An attack where the adversary has access to both the plaintext and its ciphertext.
What is a chosen-plaintext attack?
An attack where the adversary can choose the plaintext and see the resulting ciphertext.
What is a chosen-ciphertext attack?
An attack where the adversary can choose the ciphertext and see the resulting plaintext.
What is the Electronic Codebook (ECB) mode?
A block cipher mode where each block is encrypted independently.
What is the Cipher Block Chaining (CBC) mode?
A block cipher mode where each block of plaintext is XORed with the previous ciphertext block before being encrypted.
What is the Counter (CTR) mode?
A block cipher mode that turns a block cipher into a stream cipher by encrypting a counter value.
What is a hybrid encryption?
Using public-key encryption to share a symmetric key which is then used for encrypting the actual message.
What is RSA encryption?
A public-key encryption method based on the difficulty of factoring large numbers.
What is data origin authentication?
Verifying who sent a message.
What is data integrity?
Ensuring that data has not been altered.
What is non-repudiation?
Ensuring that a sender cannot deny sending a message.
What is a collision in hash functions?
When two different inputs produce the same hash value.
