AP Computer Science Principles - Unit 10 Test Review

Encrypt

Use an algorithm to encode a message

Decrypt

Use an algorithm to decode a message

Cipher

another term for encrypted message

Random Substitution Cipher

Encryption in which arbitrary symbols replace letters

Caesar Cipher

encryption scheme based on shifting the alphabet

Vigenere Cipher

encryption that shifts the alphabet differently per character

Computationally Hard

A problem that cannot be solved in a reasonable amount of time

Cracking encryption

When you attempt to decode a secret message without knowing all the specifics of the cipher, you are trying to "crack" the encryption.

asymmetric encryption

used in public key encryption, it is scheme in which the key to encrypt data is different from the key to decrypt.

private key

In an asymmetric encryption scheme the decryption key is kept private and never shared, so only the intended recipient has the ability to decrypt a message that has been encrypted with a public key.

Public Key Encryption

Used prevalently on the web, it allows for secure messages to be sent between parties without having to agree on, or share, a secret key. It uses an asymmetric encryption scheme in which the encryption key is made public, but the decryption key is kept private.

Which of the following statements is the LEAST TRUE about personal data that technology companies potentially collect about their users?

Companies are required by law to give users options to personalize what data they collect about them

What is a Caesar cipher? As part of your answer demonstrate encrypting the plaintext messages: CS IS COOL with a caesar cipher.

A Caesar cipher is a technique for encryption that shifts the alphabet by some number of characters. "CS IS COOL" as a Caesar cipher is "FV LV FRRO" when shifted 3 times down the alphabet.

What is the "key" to a Caesar Cipher that someone needs to know (or discover) to decrypt the message?

The number of characters to shift each letter in the alphabet.

The Caesar Cipher has 25 different shifts to try. How many possibilities are there to try in a random substitution cipher?

26 x 25 x 24 x***x 3 x 2 x 1

Fill in the blank of the following statement: "______ encryption is a method of encryption involving one key for both encryption and decryption."

Symmetric

A coffee shop is considering accepting orders and payments through their phone app and have decided to use public key encryption to encrypt their customers' credit card information. Is this a secure form of payment?

Yes, public key encryption is built upon computationally hard problems that even powerful computers cannot easily solve.

Which of the following statements best describes the properties of public key encryption?

Public key encryption is an encryption method which relies on separate keys for encrypting and decrypting information.

Choose the answer that is NOT a feature of Public Key Cryptography:

A Public Key database ensures 3rd party accountability of security.

Which of the following scenarios is most characteristic of a phishing attack.

You get an email from the IT support desk that asks you to send a reply email with your username and password to verify your account

Which of the following are true statements about digital certificates in Web browsers?

I. Digital certificates are used to verify the ownership of encrypted keys used in secured communication

II. Digital certificates are used to verify that the connection to a Web site is fault tolerant.

I only