QUESTIONS

Now let’s see what you recall about Blockchain technology before we move on. Answer the following questions in the space at the left to test your knowledge!

1. Proof of work
   a. is what blockchain technology is based on.
   b. allows people to get paid some kind of cryptocurrency on a blockchain.
   c. allows people to PROVE they have work on the blockchain through a transaction of some kind.
   d. All of the above
2. A blockchain
   a. is a digital ledger.
   b. makes Bitcoin and other cryptocurrencies possible.
   c. can make transactions recorded chronologically and publicly.
   d. All of the above
3. TRUE or FALSE: Cryptography is the practice of encoding information so only authorized people can read it.
4. TRUE or FALSE: Hashing is one of the types of cryptography that we can use to make data secure and is the foundation for making blockchains.
5. Hashing in a blockchain
   a. changes a transaction into an unreadable string of text for the purpose of encrypting the transaction.
   b. takes input data of arbitrary length and produces a fixed-size (always the same size) output.
   c. is generated by a mathematical formula inside of a computer program so that it is REALLY unlikely that some other transaction will produce the same hash value.
   d. All of the above

6. Which of the following of I - VI are TRUE of a blockchain?

   I. It is like a distributed database.
   II. It’s a public ledger.
   III. It can be cashed in for cryptocurrency.
   IV. It is immutable.
   V. It’s difficult to tamper with because of hashing algorithms.
   VI. They often rely on the SHA-256 hashing algorithm.

   a. I and II
   b. All except III
   c. IV, V, and VI
   d. III only

ANSWERS
1. d
2. d
3. TRUE
4. TRUE
5. d
6. b
7.