3: Explain Cryptographic Solutions

What is cryptography?

The art of making information secure by encoding it.

What is plaintext vs. ciphertext?

Plaintext is an unencrypted message; ciphertext is an encrypted message.

What is cryptanalysis?

The art of cracking cryptographic systems.

What is symmetric encryption?

An encryption algorithm where both parties use the same key for encryption and decryption.

What is asymmetric encryption?

An encryption algorithm where encryption and decryption use two different but related keys: a public key and a private key.

What is the key difference between symmetric and asymmetric encryption?

Symmetric encryption uses the same key for both parties, while asymmetric encryption uses a related public/private key pair.

What is hashing?

An algorithm that produces a fixed-length string of bits from an input that can be any length.

What makes hashing different from encryption?

Hashing is a one-way function designed to produce a fixed-length digest, meaning the original plaintext cannot normally be recovered from the digest.

What is a hash collision?

When different inputs produce the same hash output; the lesson notes that different inputs are unlikely to produce the same output.

What is a digital signature?

A message digest encrypted using the sender's private key and appended to a message to authenticate the sender and prove message integrity.

What is the basic formula for a digital signature?

Hash + private key = digital signature.

What is PKI?

Public Key Infrastructure; it aims to prove that the owners of public keys are who they claim to be.

What is a digital certificate?

A public assertion of identity that is validated by a certificate authority (CA), essentially functioning like a digital passport.

What is a certificate authority (CA)?

A server that guarantees subject identities by issuing signed digital certificate wrappers for their public keys.

What is the relationship between PKI, digital certificates, and a CA?

PKI provides the infrastructure for establishing public-key identity; a digital certificate asserts an identity and public key; the CA validates that identity by issuing the signed certificate.

What is a salt?

A random value added to plaintext input before hashing, making it harder to guess after the data is hashed.

What is key stretching?

The process of repeatedly hashing a generated key to strengthen it.

What is obfuscation?

The art of making data difficult to find.

What is steganography?

The art of hiding a secret message, file, or image inside another ordinary non-secret file or physical object.

What is data masking?

Hiding data by replacing it with fake, alternative values that appear real.

What are the three states of data?

Data at rest, data in transit (or data in motion), and data in use (or data in processing).

What is data at rest?

Data that is stored rather than actively being transmitted or processed.

What is data in transit?

Data that is being transmitted or moved between locations or systems.

What is data in use?

Data that is actively being processed or used by a system.