Hashing algorithms (SHA, MD5) in Cybersecurity - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a hashing algorithm?

A hashing algorithm is a process that takes input data and converts it into a fixed-size string of characters, which appears random. This output is called a hash and is unique to the original data.

beginner

What does MD5 stand for and what is it used for?

MD5 stands for Message Digest 5. It is a hashing algorithm used to create a 128-bit hash value, often used to check data integrity but is now considered insecure for cryptographic purposes.

intermediate

What is SHA and how is it different from MD5?

SHA stands for Secure Hash Algorithm. It produces longer hash values (like 160-bit or more) and is more secure than MD5, making it better for protecting data against tampering.

intermediate

Why are MD5 and SHA hashes considered one-way functions?

Because once data is hashed, it is practically impossible to reverse the process and get the original data back. This one-way property helps protect sensitive information.

advanced

What is a collision in hashing algorithms?

A collision happens when two different inputs produce the same hash output. This is a weakness because it can allow attackers to trick systems that rely on unique hashes.

What is the main purpose of a hashing algorithm?

A To convert data into a fixed-size unique string

B To encrypt data so it can be decrypted later

C To compress data to save space

D To generate random numbers

Hashing algorithms convert data into a fixed-size string called a hash, which uniquely represents the original data.

Which hashing algorithm is considered less secure today?

A SHA-3

B SHA-1

C SHA-256

D MD5

MD5 is considered less secure due to vulnerabilities that allow collisions.

What does a collision in hashing mean?

A Two inputs produce the same hash

B Hash cannot be generated

C Hash is too long

D Hash is reversible

A collision occurs when two different inputs produce the same hash output.

Which property makes hashing algorithms useful for passwords?

A They are reversible

B They are one-way functions

C They produce random outputs

D They compress data

Hashing algorithms are one-way, meaning original data cannot be recovered from the hash, protecting passwords.

SHA stands for:

A Secure Hacking Algorithm

B Simple Hash Application

C Secure Hash Algorithm

D Strong Hash Access

SHA stands for Secure Hash Algorithm, a family of cryptographic hash functions.

Explain what a hashing algorithm does and why it is important in cybersecurity.

Think about how data is transformed and why reversing it is hard.

Compare MD5 and SHA in terms of security and usage.

Consider their strength against attacks and common applications.