Introduction to Cryptography: Chapter 30

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What is the key used by both the sender and receiver in symmetric-key cryptography?

Same key

How many security services can network security provide?

Five services

What must be done to achieve message confidentiality?

Encrypt at sender site, decrypt at receiver site

What are the two categories of cryptography discussed in the text?

Symmetric-key cryptography and asymmetric-key cryptography Signup and view all the answers

How many services related to the message are provided by network security?

Four services Signup and view all the answers

What does encryption and decryption provide?

Secrecy or confidentiality Signup and view all the answers

What is needed to preserve the integrity of a document?

Both the document and the fingerprint Signup and view all the answers

Why can't a conventional lossless compression method be used as a hashing function?

It creates a compressed message that is reversible Signup and view all the answers

What is needed for a digital signature?

A public-key system Signup and view all the answers

What do we use in a cryptosystem and in digital signature?

Private and public keys Signup and view all the answers

How does symmetric-key cryptography use the key?

The same key is used by the sender for encryption and the receiver for decryption. The key is shared. Signup and view all the answers

What are the five services that network security can provide?

Message Confidentiality, Message Integrity, Message Authentication, Message Nonrepudiation, Entity Authentication Signup and view all the answers

How can message confidentiality be achieved?

Message must be encrypted at the sender site and decrypted at the receiver site using either symmetric-key cryptography or asymmetric-key cryptography. Signup and view all the answers

What is the concept behind achieving message confidentiality or privacy?

The message must be encrypted at the sender site and decrypted at the receiver site using either symmetric-key cryptography or asymmetric-key cryptography. Signup and view all the answers

What are the two categories of cryptography discussed in the text?

Symmetric-key cryptography and Asymmetric-key cryptography Signup and view all the answers

What is the purpose of using a lossless compression method as a hashing function?

We cannot use a lossless compression method as a hashing function because it creates a reversible compressed message. Signup and view all the answers

Why can't a checksum method be used as a hashing function?

A checksum method does not meet all the criteria for a hashing function, even though it is not reversible. Signup and view all the answers

What is the role of a hash function in message authentication?

A hash function can detect any modification in the message but cannot provide authentication. Signup and view all the answers

How does a digital signature prove the authenticity of the sender?

A digital signature proves the authenticity of the sender by ensuring that the message comes from the intended sender. Signup and view all the answers