Cryptography Module 5 Review Questions

Method of sharing the same secret key for encryption and decryption between parties.

Cryptographic keys used only once for secure communication; preventing repeated use and protecting sensitive data if a key is compromised.

A system of managing cryptographic keys in multiple levels; often involving a master key to manage other keys.

The period during which a session key is valid and used for encryption/decryption.

A unique identifier used to categorize and track cryptographic keys.

A combined approach using both symmetric and asymmetric encryption methods.

Publicly sharing a cryptography key that is used for encrypting data sent to its holder.

Canceling a digital certificate to prevent its further use and maintain security.

A method for securely exchanging secret keys over an insecure channel.

An entity that issues and manages digital certificates, verifying public keys.

A digital document that confirms the authenticity of a public key.

A structured way of organizing and managing cryptographic keys.

A temporary key used for a single encryption session.

A key used to generate other keys, often for session keys.

The process of delivering a key to parties who want to exchange data securely. Secure key distribution is crucial for encrypting and decrypting information.

In encryption, the same secret key is used for both encrypting and decrypting data. This requires the secure exchange of the same key to both parties.

Two separate keys are used: a public key for encryption, and a private key for decryption. Public keys are freely shared, private keys are kept secret.

The practice of changing encryption keys regularly. This enhances security by limiting the damage from compromised keys.

Digital certificates used to verify the identity of entities in a network.

Ways to share public keys securely. Examples include public announcements, public-key authorities, public-key certificates.

A type of attack where an attacker intercepts communication between two parties, impersonating one of them to steal sensitive information. This type of hacking is particularly dangerous in key exchange processes.

An asymmetric cryptographic system used for both encryption and digital signatures. It uses a public and private key pair, but not the same algorithms as RSA.

To ensure the confidentiality, integrity, and availability of information. This means protecting data from unauthorized access, modification, or disruption.

A type of cryptography where the same key is used for both encryption and decryption. This key must be shared securely between the communicating parties.

To verify the authenticity and integrity of a message or document. It guarantees that the message was sent by the claimed sender and hasn't been tampered with.

A one-way mathematical function that transforms data into a fixed-length hash value. SHA-256 is a widely used standard in digital signatures, creating a unique fingerprint for the message.

The process of transforming plaintext into ciphertext, making it unreadable without the decryption key.

Uses a single secret key for both encrypting and decrypting data. Both parties need the same key.

Uses two separate keys: a public key for encryption and a private key for decryption. Only the private key can decrypt data encrypted with the corresponding public key.

A unique random number generated for each message to prevent replay attacks. It ensures that a message hasn't been sent before and guarantees its freshness.

To securely distribute cryptographic keys between parties without revealing them to eavesdroppers. It enables secure communication without sharing keys directly.

Public key cryptography provides enhanced security through key separation, where the private key is kept secret and the public key is shared. This ensures that only the intended recipient can decrypt encrypted messages and verify digital signatures.

A digital signature is a code attached to a message that guarantees its source and integrity. It verifies that the message is genuine and hasn't been tampered with.

In digital signatures, a hash function compresses the message into a fixed-sized fingerprint (hash). This hash is signed and used for verification. If the message changes, the hash will change, revealing tampering.

A key-only attack aims to determine the signer's private key using only their public key. The attacker attempts to deduce the private key based on the public key's structure and mathematical properties.

Digital signatures provide non-repudiation by ensuring that the sender cannot deny having signed the message. It verifies the sender's identity and prevents them from claiming they didn't sign it.

The inverse cryptographic transformation in a cryptosystem is the process of decryption. It uses the appropriate key (either private or shared) to convert encrypted data back into its original form.

A symmetric cryptosystem uses the same key for both encryption and decryption. This means the sender and receiver must share the same secret key to communicate securely.

A cryptographic transformation is a process that converts input data into output data using a cryptographic key. This includes both encryption and decryption.