2_ HASHING ACTIVITY

CLASS LAB 8-2: HASHING ACTIVITY

Countermeasures Against Cyberattacks

Asymmetric Cryptography

HASHING ACTIVITY

Instructions: This activity provides experience running hash functions and seeing what hash function outputs look like, as well as how they can sometimes be broken.

Files or Resources Needed: To complete Task 1 of this activity, you will be using the website http://www.fileformat.info/tool/hash.htm to compute hash function outputs. To complete Task 2 you will use the website https://www.md5online.org/md5-decrypt.html.

TASK 1: GENERATING HASHES FROM STRINGS

Let’s take a look at some inputs to hash functions and their corresponding outputs. Use the website http://www.fileformat.info/tool/hash.htm to convert the strings to hashes. Record the hash function outputs in the appropriate places in the table.

String	MD5	SHA-1
password	5f4dcc3b5aa765d61d8327deb882cf99	5baa61e4c9b93f3f0682250b6cf8331b7ee68fd8
Password	dc647eb65e6711e155375218212b3964	8be3c943b1609fffbfc51aad666d0a04adf83c9d
Password!	0040f2abc2cff0c8f59883b99ae9fab6	ef8420d70dd7676e04bea55f405fa39b022a90c8
!Password	9a8896ebf2e4a99e4b1c0174504c898a	4533c662e44139873ae2fd3ce1fd3dbbf08b8c92

Notice how different each hash value is for each string. This pseudo-randomness gives hash functions their power!

QUESTION 1-1: To the average user, what makes MD5, SHA-1, and other hash function outputs different from each other?

Different hash functions use different hashing algorithms to output different numerical values for each string.

TASK 2: CRACKING HASHES

You might wonder why there are a variety of hash functions available. This is primarily because over time some have been proven insecure for modern use. As such, cryptographic hash functions like MD5 and SHA-1 are used primarily for purposes such as verifying the authenticity of files. As computational power continues to increase, researchers must keep up by developing new or stronger hash functions. The next frontier of securing encrypting is to be resistant to the evolving field of quantum computers.

Since hash functions by their nature are nearly impossible to reverse, decrypting hash functions is a challenge. A common technique to decrypting them is to develop Lookup Tables, also sometimes known as Rainbow Tables. These tables contain known strings and their corresponding hash values. You can see just how big some Rainbow Tables are by looking at the file sizes at https://freerainbowtables.com/.

Below are some hash values, try to use https://www.md5online.org/md5-decrypt.html and see if you can figure out what the original values are!

Hint: look under the Decrypt button for the output. If the hash is in the lookup table, the output says “Found:” followed by the text that used to create the hash.

MD5 Hash	Hashed Text
e91e6348157868de9dd8b25c81aebfb9	security
4862ee9c9b69ca7c7ac6e012cd7665b7	requires
f068fc985d0a439e5a126d78a28cc4c9	stronger
b2803b5602c2d8dc3cecb9ec7dee659c	techniques