To generate a hash value from a given message

T.A. Yang

· The following program is originally from the geeksforgeeks.org site, https://www.geeksforgeeks.org/hashlib-module-in-python/.

# importing hashlib for getting sha256() hash function

import hashlib

# A string that has been stored as a byte stream

# (due to the prefix b)

string = b"My name is apple and I am a vegetable?"

# Initializing the sha256() method

sha256 = hashlib.sha256()

# Passing the byte stream as an argument

sha256.update(string)

# sha256.hexdigest() hashes all the input data

# passed to the sha256() via sha256.update()

# Acts as a finalize method, after which all

# the input data gets hashed

# hexdigest() hashes the data, and returns

# the output in hexadecimal format

string_hash = sha256.hexdigest()

print(f"Hash:{string_hash}")

EX1: Save this program into a file as a Python file, say hashing1.py and then run that Python script to generate the hash value from the given message.

NOTE: In the following screenshot it is assumed that the file hashing1.py is stored under the folder c:\csci3341dir. If you save the file in another folder, use that folder name instead.

To hand in:

a. A screenshot showing you have successfully run the given script.

b. Answer the following questions.

Q1: How many bytes are produced as the hash value when you run the sha256 hashing function?

Ans1:

c. What hash value would be generated by the script if you change only a single character in the message? For example, change the message to "My name is apple and I am a vegetable." (That is, replace ? with a period.) As shown in the screenshot below, a different hash is produced. Revise the script and hand in a screenshot of running the revised script.