How have you used hashing in your projects before…

I used hashing for the following purposes:

Password management: Storing one-way hashed passwords instead of plain text for increased security.

# Example of using bcrypt for password hashing
import bcrypt

password = b"mysecretpassword"
# Generate salt and hash the password
hashed_password = bcrypt.hashpw(password, bcrypt.gensalt())
print(hashed_password)

# Password verification
is_valid = bcrypt.checkpw(password, hashed_password)
print(is_valid)

Data integrity verification: Hashing files or data to ensure their immutability. SHA256 algorithms were used.

# Example of verifying file integrity using SHA256
import hashlib

def hash_file(filepath):
    hasher = hashlib.sha256()
    with open(filepath, 'rb') as f:
        while chunk := f.read(4096):
            hasher.update(chunk)
    return hasher.hexdigest()

file_hash = hash_file("my_important_document.txt")
print(file_hash)

Caching: Using hash keys for quick access to cache entries, for example, when working with Redis.

# Example of using hashing for cache key
import hashlib
import redis

r = redis.StrictRedis(decode_responses=True)

def get_cached_data(key):
    # Create hash of the key
    cache_key_hash = hashlib.sha256(key.encode()).hexdigest()
    data = r.get(cache_key_hash)
    if data:
        print("Data from cache")
        return data
    else:
        print("Data not in cache")
        # Simulate fetching data from source
        source_data = f"Data for key: {key}"
        # Save to cache with hashed key
        r.set(cache_key_hash, source_data, ex=60) # expire in 60 seconds
        return source_data

print(get_cached_data("user:123:profile"))
print(get_cached_data("user:123:profile")) # Second time from cache

Data structures: Internal use of hashing in Python dictionaries (dict) and sets for efficient lookup and storage of unique elements.

# Python dict and set use hashing
my_dict = {"key1": "value1", "key2": "value2"}
my_set = {"item1", "item2", "item1"}

print(my_dict["key1"]) # Fast access by hash
print(my_set)          # Unique elements, determined by hash

Depending on the task, an appropriate hashing algorithm and library (e.g., hashlib, bcrypt) were chosen.

How have you used hashing in your projects before?