Blockchain Development Final UPDATED
ACTUAL Exam Questions and CORRECT
Answers
Why is establishing identity and ensuring privacy and security difficult in decentralized systems?
- CORRECT ANSWER - This is difficult because in decentralized systems there is no
notion of a user identity such as usernames and a central database for storing authentication data
such as passwords. Also, there are no frameworks in place to ensure the privacy of user data such
as HIPAA for medical information and FERPA for student records.
What is cryptography used for in decentralized systems? - CORRECT ANSWER --
Creating a digital identity
- Securing data and transactions
- Ensuring privacy of data
- Signing documents digitally
What is symmetric cryptography and why is it an issue in decentralized systems? - CORRECT
ANSWER - Symmetric cryptography is where the same key is used for both encryption
and decryption. This is an issue in decentralized systems as it becomes difficult to safely share
the key amongst multiple individuals. If the key is stolen, then an adversary can easily decrypt
encrypted data.
What is asymmetric cryptography and why is it a better fit for decentralized networks? -
CORRECT ANSWER - Asymmetric cryptography is where we have two keys a private
key and a public key. The private key is only known to the holder and the public key is publicly
available. Also, anything encrypted with the private key can only be decrypted with the public
key and vice versa. This is a better fit for decentralized systems because an individual can
encrypt data with their private key and their publicly available public key is able to decrypt it
which makes sharing keys easier. It also allows for verification as if an individual's public key
can decrypt data it means their private key encrypted it which proves identity.
How are Ethereum addresses generated? - CORRECT ANSWER - - 256-bit random
number becomes private key.
, - An elliptic curve algorithm is used to derive a public key from the private key.
- A hashing 160-bit hashing function is used to generate an address from the public key.
If someone steals your private key, what does it give them access to? - CORRECT
ANSWER - They will have access to all your accounts and tokens within your wallet.
What does Metamask use to sign your transactions? - CORRECT ANSWER - Your private
key
How does the BIP39 standard create a mnemonic? - CORRECT ANSWER - - A 128-bit
entropy is generated from your private key.
- A 4-bit checksum is added to it to make it 132-bits.
- It is then divided into 11-bit parts with each part mapping onto a word from a 2048- word list.
How does a hash function work? - CORRECT ANSWER - Transforms data of an arbitrary
size to a fixed size value.
What items are hashed in the blockchain world? - CORRECT ANSWER - Block,
transactions, data.
What are the uses of hashing? - CORRECT ANSWER - - Digitally signing documents
- Hash block header
- Hash data on distributed ledger (for storing large data off chain)
What are 3 hash functions provided by solidity? - CORRECT ANSWER - - RIPEMD160
- SHA256
- Keccak (256)
What are the different kinds of on-chain data? - CORRECT ANSWER - - Blocks
ACTUAL Exam Questions and CORRECT
Answers
Why is establishing identity and ensuring privacy and security difficult in decentralized systems?
- CORRECT ANSWER - This is difficult because in decentralized systems there is no
notion of a user identity such as usernames and a central database for storing authentication data
such as passwords. Also, there are no frameworks in place to ensure the privacy of user data such
as HIPAA for medical information and FERPA for student records.
What is cryptography used for in decentralized systems? - CORRECT ANSWER --
Creating a digital identity
- Securing data and transactions
- Ensuring privacy of data
- Signing documents digitally
What is symmetric cryptography and why is it an issue in decentralized systems? - CORRECT
ANSWER - Symmetric cryptography is where the same key is used for both encryption
and decryption. This is an issue in decentralized systems as it becomes difficult to safely share
the key amongst multiple individuals. If the key is stolen, then an adversary can easily decrypt
encrypted data.
What is asymmetric cryptography and why is it a better fit for decentralized networks? -
CORRECT ANSWER - Asymmetric cryptography is where we have two keys a private
key and a public key. The private key is only known to the holder and the public key is publicly
available. Also, anything encrypted with the private key can only be decrypted with the public
key and vice versa. This is a better fit for decentralized systems because an individual can
encrypt data with their private key and their publicly available public key is able to decrypt it
which makes sharing keys easier. It also allows for verification as if an individual's public key
can decrypt data it means their private key encrypted it which proves identity.
How are Ethereum addresses generated? - CORRECT ANSWER - - 256-bit random
number becomes private key.
, - An elliptic curve algorithm is used to derive a public key from the private key.
- A hashing 160-bit hashing function is used to generate an address from the public key.
If someone steals your private key, what does it give them access to? - CORRECT
ANSWER - They will have access to all your accounts and tokens within your wallet.
What does Metamask use to sign your transactions? - CORRECT ANSWER - Your private
key
How does the BIP39 standard create a mnemonic? - CORRECT ANSWER - - A 128-bit
entropy is generated from your private key.
- A 4-bit checksum is added to it to make it 132-bits.
- It is then divided into 11-bit parts with each part mapping onto a word from a 2048- word list.
How does a hash function work? - CORRECT ANSWER - Transforms data of an arbitrary
size to a fixed size value.
What items are hashed in the blockchain world? - CORRECT ANSWER - Block,
transactions, data.
What are the uses of hashing? - CORRECT ANSWER - - Digitally signing documents
- Hash block header
- Hash data on distributed ledger (for storing large data off chain)
What are 3 hash functions provided by solidity? - CORRECT ANSWER - - RIPEMD160
- SHA256
- Keccak (256)
What are the different kinds of on-chain data? - CORRECT ANSWER - - Blocks
