49. OCR A Level (H446) SLR9 – 1.3 Hashing

What does a hashing function do?

• Decompresses data files

• Transforms a string of characters into a fixed length value

• Translates one programming language into another

• Encrypts data into an unreadable format

Answer explanation

A hashing function transforms a string of characters into a fixed length value, making it the correct choice among the options provided.

Which of the following is a popular hashing algorithm?

• Blowfish

• AES

• RSA

• SHA1

Answer explanation

SHA1 is a popular hashing algorithm known for its cryptographic security and widely used in various applications.

What happens if even a slight change is made to the original message in hashing?

• It produces a totally different hash value

• The hash value remains unchanged

• The change is ignored by the hashing function

• It results in an error

Answer explanation

Even a slight change in the original message in hashing will produce a totally different hash value, highlighting the correct choice.

How is hashing different from other encryption techniques?

• Hashing requires a key to decrypt

• Hashing can easily be reversed

• Hashing is slower than encryption

• Hashing is a one-way process

Answer explanation

Hashing is a one-way process, meaning it cannot be reversed to obtain the original input. Unlike encryption, hashing does not require a key for decryption.

Why is hashing ideal for storing passwords?

• It makes passwords easier to remember

• It reduces the size of the password

• It prevents passwords from being read by hackers

• It encrypts the password into a readable format

Answer explanation

Hashing is ideal for storing passwords because it prevents passwords from being read by hackers, adding a layer of security to the stored data.

What is the benefit of not storing passwords in plain text?

• Enhances security by making it difficult for hackers to obtain actual passwords

• Makes the system run faster

• Saves storage space

• Allows users to retrieve their passwords easily

Answer explanation

The benefit of not storing passwords in plain text is that it enhances security by making it difficult for hackers to obtain actual passwords.

How does the system verify a user's password during login when hashing is used?

• By decrypting the stored password

• By sending a verification code to the user's email

• By comparing the hash value of the entered password with the stored hash value

• By asking security questions

Answer explanation

The system verifies a user's password during login by comparing the hash value of the entered password with the stored hash value, ensuring secure authentication without needing to decrypt the stored password.

What is one of the uses of hashing besides storing passwords?

• Generating random numbers

• Quick searching, insertion, and deletion of data from data structures

• Compressing data files

• Improving the graphics of video games

Answer explanation

Hashing is used for quick searching, insertion, and deletion of data from data structures, making it a valuable tool beyond just storing passwords.

What is the time complexity advantage of using hashing for data retrieval?

• Provides a constant O(1) time complexity

• Has a quadratic time complexity O(n^2)

• Has a linear time complexity O(n)

• Has a logarithmic time complexity O(log n)

Answer explanation

Using hashing for data retrieval provides a constant O(1) time complexity, making it advantageous for quick access to data.

Why can't hashed passwords be reverse-engineered?

• Because hashing is a one-way process

• Because the passwords are too complex

• Because the passwords are encrypted

• Because the hashing algorithm is secret

Answer explanation

Hashed passwords cannot be reverse-engineered because hashing is a one-way process, meaning the original password cannot be obtained from the hash value.