Cryptography Basics

What is cryptography?

• Cryptography is the practice of baking pastries

• Cryptography is the practice and study of techniques for secure communication in the presence of third parties.

• Cryptography is the study of marine biology

• Cryptography is the art of making pottery

Explain the difference between encryption and decryption.

• Encryption converts plaintext to ciphertext, while decryption converts ciphertext to plaintext.

• Encryption is used for compressing data, while decryption is used for decompressing data.

• Encryption converts ciphertext to plaintext, while decryption converts plaintext to ciphertext.

• Encryption and decryption are the same process.

What is a key in cryptography?

• A key in cryptography is a musical instrument

• A key in cryptography is a piece of information used to encrypt or decrypt data.

• A key in cryptography is a mode of transportation

• A key in cryptography is a type of food

Describe the difference between symmetric and asymmetric encryption.

• Symmetric encryption is only used for data at rest, while asymmetric encryption is used for data in transit.

• Symmetric encryption uses different keys for encryption and decryption, while asymmetric encryption uses the same key for both.

• Symmetric encryption is more secure than asymmetric encryption.

• The main difference is in the number of keys used and their roles in the encryption process.

What is a Caesar cipher and how does it work?

• A Caesar cipher is a type of transposition cipher where letters are rearranged in a specific pattern.

• A Caesar cipher is a type of steganography technique involving image manipulation.

• A Caesar cipher is a type of substitution cipher where each letter in the plaintext is shifted a certain number of places down or up the alphabet.

• A Caesar cipher is a type of encryption that uses quantum computing principles.

What is a substitution cipher?

• A substitution cipher is a method of encryption where each letter in the plaintext is replaced with another letter according to a fixed system.

• A substitution cipher is a method of encoding where each letter in the plaintext is shifted by a fixed number of positions in the alphabet.

• A substitution cipher is a method of encryption where numbers are replaced with letters according to a fixed system.

• A substitution cipher is a method of decryption where each letter in the plaintext is replaced with another letter according to a fixed system.

Explain the concept of a public key in asymmetric encryption.

• A public key is only used for decryption

• A public key in asymmetric encryption is used to encrypt data that can only be decrypted by the corresponding private key.

• A public key is used for symmetric encryption

• A public key is shared with everyone in private

What is the importance of randomness in generating cryptographic keys?

• Randomness increases the likelihood of successful attacks on cryptographic keys.

• Randomness is irrelevant in the generation of cryptographic keys.

• Randomness ensures uniformity and simplicity in key generation.

• Randomness ensures unpredictability and resistance against attacks.

What is a hash function and how is it used in cryptography?

• Hash functions are only used for compressing data in cryptography.

• In cryptography, hash functions are primarily used for encrypting messages.

• A hash function is a mathematical algorithm that takes an input and produces a fixed-size string of bytes, which is typically a unique representation of the input. In cryptography, hash functions are used for various purposes like password hashing, digital signatures, and data integrity verification.

• A hash function is a type of encryption used to hide data in plain sight.

Discuss the concept of digital signatures in cryptography.

• Digital signatures do not provide any security benefits.

• Digital signatures are only used for symmetric encryption.

• Digital signatures are used for encrypting data at rest.

• Digital signatures in cryptography provide a way to verify the authenticity, integrity, and non-repudiation of digital messages or documents by using asymmetric encryption techniques.