Understanding Cryptographic Hashes and Digital Signatures

The video tutorial explains cryptographic hashes, their uses, and how they differ from encryption. It covers the SHA-256 hashing algorithm, hash collisions, and the issues with MD5. Practical applications of hashing, such as file verification and password storage, are discussed. The video also details the process and importance of digital signatures in ensuring data integrity, authentication, and non-repudiation.

What is a cryptographic hash primarily used for?

• Representing data as a short string

• Compressing files

• Generating random numbers

• Encrypting data

How does a minor change in input affect a SHA-256 hash?

• It makes the hash longer

• It has no effect on the hash

• It produces a completely different hash

• It results in a slightly different hash

Why is the MD5 hashing algorithm no longer recommended?

• It has collision problems

• It is too slow

• It produces too large hashes

• It is not compatible with modern systems

What is the purpose of adding a salt to a password hash?

• To make the hash shorter

• To prevent hash collisions

• To make it harder to reverse-engineer the hash

• To encrypt the password

How can you verify that a downloaded file is authentic?

• By opening it in a text editor

• By comparing its hash with the one on the website

• By running an antivirus scan

• By checking its file size

What does a digital signature ensure about a message?

• It is compressed

• It is free of viruses

• It is from a trusted source

• It is encrypted

Which key is used to create a digital signature?

• Public key

• Private key

• Symmetric key

• Session key

What happens if a digital signature cannot be verified with the sender's public key?

• The message is compressed

• The message is deleted

• The message is considered altered

• The message is encrypted

In the email example, what is the first step in creating a digital signature?

• Encrypting the message

• Hashing the plain text

• Sending the message

• Decrypting the message

What is the role of Alice's public key in the email example?

• To send the message

• To verify the digital signature

• To hash the message

• To encrypt the message