10.3 Applied Cryptography and Attacks

Question 1

Encryption can be used to secure portable devices like laptops and cell phones. Most current operating systems use _______ to prevent unauthorized parties from viewing the data on the machine.

Answer 1

disk encryption

Encryption can be used to secure portable devices like laptops and cell phones. Most current operating systems use disk encryption to prevent unauthorized parties from viewing the data on the machine.

Microsoft Windows uses a symmetric disk encryption program called BitLocker.

Macs use a symmetric disk encryption program called FileVault.

Question 2

True or False

Emails are natively encrypted. They are sent and received in plaintext.

Answer 2

False

Emails are NOT natively encrypted. They are sent and received in plaintext.

Question 3

Programs like _____ and _____ can apply
public key cryptography to provide email
confidentiality and use digital signatures
to ensure authenticity and integrity.

Answer 3

Programs like S/MIME and PGP can apply public key cryptography to provide email confidentiality and use digital signatures
to ensure authenticity and integrity.

Question 4

___________ is a protocol

designed to encrypt web traffic.

Answer 4

Secure Socket Layer (SSL) is a protocol
designed to encrypt web traffic.

○ HTTPS actually stands HTTP over SSL.

These certificates use public key cryptography to establish a secure connection between the browser and the server.

Question 5

A _________ is a cybersecurity professional who captures and investigates digital evidence from computers, cell phones, and other devices containing digital data.

Answer 5

A forensic examiner is a cybersecurity professional who captures and investigates digital evidence from computers, cell phones, and other devices containing digital data.

Question 6

True or False

Forensic examiners make a hash of
a device when it is initially collected
for investigation.

Answer 6

True

Question 7

_________ is the cryptographic technique of placing hidden messages
within files, images, or videos.

Answer 7

Steganography is the cryptographic technique of placing hidden messages within files, images, or videos.

Question 8

_________ are small data files that use public key

cryptography to secure connections between the browser and the web server.

Answer 8

SSL certificates are small data files that use public key cryptography to secure connections between the browser and the web server.

Question 9

To get an SSL, an organization must first reach out to a ___________ , an organization responsible for issuing SSL certificates.

Answer 9

To get an SSL, an organization must first reach out to a certificate authority (CA), an organization responsible for issuing SSL certificates.

Question 10

What information does a CA need to get a SSL certificate?

Answer 10

• Company documents
• A unique IP address
• A certificate signing request (CSR), a block of encrypted data that is created on the web server where the SSL certificate will eventually be installed.

Question 11

When generating the CSR, a _______ and _______ pair are created.

Answer 11

When generating the CSR, a private and public key pair are created.

• Only the public key is sent to the CA.
• The private key remains hidden on the webserver.

Question 12

SSL certificates validate authenticity using a _______.

Answer 12

SSL certificates validate authenticity using a chain of trust.

Question 13

Browsers have a pre-established list of trusted CAs, called a _________.

Answer 13

Browsers have a pre-established list of trusted CAs, called a ________.

Root certificate authorities are a list of CAs trusted by your browser. They’re at the top of the trust chain and are typically not the organizations that issue SSL certificates.

Intermediate certificate authorities usually issue certificates and report up to a root certificate authority.

Question 14

Explain the process of an SSL certificate

Answer 14

1. When we access a secure website, the browser asks the web server for certificate details.
2. The server responds with a copy of the SSL certificate and the public key.
3. The browser validates the certificate by checking the expiration date and root CA.
4. The browser uses the server’s public key to create, encrypt, and send a session key.
5. The server decrypts the key, sends an acknowledgement, and starts an encrypted session.
6. Secure web traffic begins. Server and browser encrypt/decrypt data with the session key.

Question 15

What does SSL stand for?

Answer 15

Secure Socket Layer

Question 16

What’s the difference between SSL and TLS?

Answer 16

SSL refers to Secure Sockets Layer whereas TLS refers to Transport Layer Security. Basically, they are one and the same, but, entirely different.

How similar both are? SSL and TLS are cryptographic protocols that authenticate data transfer between servers, systems, applications and users. For example, a cryptographic protocol encrypts the data that is exchanged between a web server and a user.

Question 17

A _____________ exploits weakness in cryptographic algorithms by attempting to determine if the “random” values produced are actually predictable.

Answer 17

A statistical attack exploits weakness in cryptographic algorithms by attempting to determine if the “random” values produced are actually predictable.

Question 18

Give some examples of a cryptographic attacks

Answer 18

1. Predictable token-generation
2. Brute force attacks
3. Birthday attack (Also known as collision and hashing collision.)
4. Frequency Analysis
5. Replay attacks

Question 19

What are rainbow tables?

Answer 19

Rainbow tables are resources that contain precomputed hashes with the associated plaintext passwords.

• Some rainbow tables are extremely large.
• They can take up a lot of storage space and CPU to use effectively.

Question 20

We can defend against rainbow tables by _________, a cryptographic method of combining salt (a random value) with the plaintext into the hash function.

Answer 20

We can defend against rainbow tables by salting, a cryptographic method of combining salt (a random value) with the plaintext into the hash function.

Question 21

_______ is a command-line tool that can automate the cracking of hashes.

Answer 21

Hashcat is a command-line tool that can automate the cracking of hashes.

Question 22

Hashcat uses ______, ______ and ______methods to figure out plaintext passwords from hashes.

Answer 22

Hashcat uses dictionary wordlists, rainbow tables, and brute force methods to figure out plaintext passwords from hashes.