1.
def caeser(text,mode,key):
    res=""
    for i in text:
        if i.islower():
            if mode=="encrypt":
                res+=chr((ord(i)+key-97)%26+97)
            else:
                res+=chr((ord(i)-key-97)%26+97)
        elif i.isupper():
            if mode=="encrypt":
                res+=chr((ord(i)+key-65)%26+65)
            else:
                res+=chr((ord(i)-key-65)%26+65)
        else:
            res+=i
    return res

print(caeser("KHOOR zruog","decrypt",3))


2.
def encrypt(text,rails):
    text=text.replace(" ","").upper()
    fence=[[] for i in range(rails)]
    rail=0
    step=1
    for i in text:
        fence[rail].append(i)
        rail+=step
        if rail==0 or rail==rails-1:
            step*=-1
    cipher=""
    for i in fence:
        cipher+="".join(i)
    print(cipher)
encrypt("geeks for geeks",3)

def decrypt(cipher,rails):
    fence=[[""]*len(cipher) for i in range(rails)]
    rail=0
    step=1
    for i in range(len(cipher)):
        fence[rail][i]="*"
        rail+=step
        if rail==0 or rail==rails-1:
            step*=-1
    k=0
    for i in range(rails):
        for j in range(len(cipher)):
            if fence[i][j]=="*":
                fence[i][j]=cipher[k];k+=1
    text=""
    rail=0
    step=1
    for i in range(len(cipher)):
        text+=fence[rail][i]
        rail+=step
        if rail==0 or rail==rails-1:
            step*=-1
    print(text)
decrypt("GSGSEKFREKEOE",3)


3.
import hashlib
def hashing(password):
    sha=hashlib.sha256()
    enco=password.encode("utf-8")
    sha.update(enco)
    return sha.hexdigest()

print((hashing("")))


4.
import hashlib
import requests
def check_pwned(password):
    hash_pass=hashlib.sha1(password.encode("utf-8")).hexdigest().upper()
    prefix=hash_pass[:5]
    suffix=hash_pass[5:]
    url=f"https://api.pwnedpasswords.com/range/{prefix}"
    response=requests.get(url)
    if response.status_code!=200:
        return -1
    hash=response.text.splitlines()
    for i in hash:
        suffiix,count=i.split(":")
        if suffix==suffiix:
            return int(count)
f=open("meri.txt")
for i in f:
    l=i.strip()
    username,password=l.split(",")
    c=check_pwned(password)
    if c<0:
        print("api error")
    elif c>0:
        print("pass found ",c)
    else:
        print("pass not found")

For this if required
pip install requests


meri.txt file content format-,
username1,password1
username2,password2


5.
import random
f=open("diction.txt")
w=f.readlines()
for i in range(len(w)):
    w[i]=w[i].strip("\t\n")
rlist=random.sample(w,3)
print("".join(rlist))
f.close()


diction.txt
mountain
silent
climb
journey
ocean
brilliant
whisper
inspire
shadow
emerald
discover
courage
wizard
hidden
wander
triumph
rocket


6.
import itertools
import string
password = "dogyy"   # the target password (small for demo)
chars = string.ascii_lowercase  # allowed characters: a–z
attempts = 0
for length in range(1, 6):  # try length 1 to 5
    for combo in itertools.product(chars, repeat=length):
        attempts += 1
        guess = "".join(combo)
        if guess == password:
            print("Password found:", guess)
            print("Attempts:", attempts)
            exit()
print("Password not found")