Homework02 Новицкая 1.2

homework01/01допзадание.py

@@ -0,0 +1,33 @@
+def encrypt_poly_shift(plaintext: str, odd_shift: int, even_shift: int) -> str:
+    alphabet = "абвгдежзийклмнопрстуфхцчшщъыьэюя"
+    alphabet_length = len(alphabet)
+
+    encrypted_text = []
+
+    for index, char in enumerate(plaintext):
+        position = index + 1
+
+        if char.lower() in alphabet:
+            shift = odd_shift if position % 2 != 0 else even_shift
+
+            original_index = alphabet.index(char.lower())
+
+            new_index = (original_index + shift) % alphabet_length
+
+            encrypted_char = alphabet[new_index]
+
+            if char.isupper():
+                encrypted_text.append(encrypted_char.upper())
+            else:
+                encrypted_text.append(encrypted_char)
+        else:
+            encrypted_text.append(char)
+
+    return "".join(encrypted_text)
+
+
+plaintext = input()
+odd_shift = int(input())
+even_shift = int(input())
+encrypted = encrypt_poly_shift(plaintext, odd_shift, even_shift)
+print(encrypted)

homework01/caesar.py

@@ -2,31 +2,58 @@ def encrypt_caesar(plaintext: str, shift: int = 3) -> str:
     """
     Encrypts plaintext using a Caesar cipher.
     >>> encrypt_caesar("PYTHON")
-    'SBWKRQ'
+    "SBWKRQ"
     >>> encrypt_caesar("python")
-    'sbwkrq'
+    "sbwkrq"
     >>> encrypt_caesar("Python3.6")
-    'Sbwkrq3.6'
+    "Sbwkrq3.6"
     >>> encrypt_caesar("")
-    ''
+    ""
     """
     ciphertext = ""
-    # PUT YOUR CODE HERE
+    for char in plaintext:
+        if char.isalpha():
+            if char.islower():
+                if ord(char) < ord("z") - shift + 1:
+                    ciphertext += chr(ord(char) + shift)
+                else:
+                    ciphertext += chr(ord(char) + shift - 26)
+            else:
+                if ord(char) < ord("Z") - shift + 1:
+                    ciphertext += chr(ord(char) + shift)
+                else:
+                    ciphertext += chr(ord(char) + shift - 26)
+        else:
+            ciphertext += char
     return ciphertext
 
 
 def decrypt_caesar(ciphertext: str, shift: int = 3) -> str:
     """
     Decrypts a ciphertext using a Caesar cipher.
+
     >>> decrypt_caesar("SBWKRQ")
-    'PYTHON'
+    "PYTHON"
     >>> decrypt_caesar("sbwkrq")
-    'python'
+    "python"
     >>> decrypt_caesar("Sbwkrq3.6")
-    'Python3.6'
+    "Python3.6"
     >>> decrypt_caesar("")
-    ''
+    ""
     """
     plaintext = ""
-    # PUT YOUR CODE HERE
-    return plaintext
+    for char in ciphertext:
+        if char.isalpha():
+            if char.islower():
+                if ord(char) > ord("a") + shift - 1:
+                    plaintext += chr(ord(char) - shift)
+                else:
+                    plaintext += chr(ord(char) - shift + 26)
+            else:
+                if ord(char) > ord("A") + shift - 1:
+                    plaintext += chr(ord(char) - shift)
+                else:
+                    plaintext += chr(ord(char) - shift + 26)
+        else:
+            plaintext += char
+    return plaintext

homework01/rsa.py

@@ -12,8 +12,17 @@ def is_prime(n: int) -> bool:
     >>> is_prime(8)
     False
     """
-    # PUT YOUR CODE HERE
-    pass
+    count = 0
+    for i in range(2, n - 1):
+        if abs(n) % i == 0:
+            count += 1
+            break
+    if n <= 1:
+        count += 1
+    if count == 0:
+        return True
+    else:
+        return False
 
 
 def gcd(a: int, b: int) -> int:
@@ -24,8 +33,11 @@ def gcd(a: int, b: int) -> int:
     >>> gcd(3, 7)
     1
     """
-    # PUT YOUR CODE HERE
-    pass
+    m = 0
+    for i in range(1, max(a, b) + 1):
+        if a % i == 0 and b % i == 0 and i > m:
+            m = i
+    return m
 
 
 def multiplicative_inverse(e: int, phi: int) -> int:
@@ -35,21 +47,24 @@ def multiplicative_inverse(e: int, phi: int) -> int:
     >>> multiplicative_inverse(7, 40)
     23
     """
-    # PUT YOUR CODE HERE
-    pass
+    d = 1
+    if (e == 1) or (phi == 1):
+        d = 0
+    else:
+        while (d * e) % phi != 1:
+            d += 1
+
+    return d
 
 
 def generate_keypair(p: int, q: int) -> tp.Tuple[tp.Tuple[int, int], tp.Tuple[int, int]]:
     if not (is_prime(p) and is_prime(q)):
         raise ValueError("Both numbers must be prime.")
     elif p == q:
         raise ValueError("p and q cannot be equal")
+    n = p * q
 
-    # n = pq
-    # PUT YOUR CODE HERE
-
-    # phi = (p-1)(q-1)
-    # PUT YOUR CODE HERE
+    phi = (p - 1) * (q - 1)
 
     # Choose an integer e such that e and phi(n) are coprime
     e = random.randrange(1, phi)
@@ -82,7 +97,7 @@ def decrypt(pk: tp.Tuple[int, int], ciphertext: tp.List[int]) -> str:
     # Unpack the key into its components
     key, n = pk
     # Generate the plaintext based on the ciphertext and key using a^b mod m
-    plain = [chr((char ** key) % n) for char in ciphertext]
+    plain = [chr((char**key) % n) for char in ciphertext]
     # Return the array of bytes as a string
     return "".join(plain)
 
@@ -100,4 +115,4 @@ def decrypt(pk: tp.Tuple[int, int], ciphertext: tp.List[int]) -> str:
     print("".join(map(lambda x: str(x), encrypted_msg)))
     print("Decrypting message with public key ", public, " . . .")
     print("Your message is:")
-    print(decrypt(public, encrypted_msg))
+    print(decrypt(public, encrypted_msg))

homework01/vigenere.py

@@ -8,8 +8,37 @@ def encrypt_vigenere(plaintext: str, keyword: str) -> str:
     >>> encrypt_vigenere("ATTACKATDAWN", "LEMON")
     'LXFOPVEFRNHR'
     """
+
+    if len(plaintext) > len(keyword):
+        diff = len(plaintext) - len(keyword)
+        for i in range(diff):
+            keyword += keyword[i]
+    nums = []
     ciphertext = ""
-    # PUT YOUR CODE HERE
+
+    for i in range(len(keyword)):
+        if keyword[i].isalpha():
+            if keyword[i].islower():
+                nums.append((ord(keyword[i]) - ord("a")) % 26)
+            else:
+                nums.append((ord(keyword[i]) - ord("A")) % 26)
+        else:
+            nums.append(0)
+
+    for i in range(len(nums)):
+        if plaintext[i].isalpha():
+            if plaintext[i].islower():
+                if ord(plaintext[i]) + nums[i] <= ord("z"):
+                    ciphertext += chr(ord(plaintext[i]) + nums[i])
+                else:
+                    ciphertext += chr(ord(plaintext[i]) + nums[i] - 26)
+            else:
+                if ord(plaintext[i]) + nums[i] <= ord("Z"):
+                    ciphertext += chr(ord(plaintext[i]) + nums[i])
+                else:
+                    ciphertext += chr(ord(plaintext[i]) + nums[i] - 26)
+        else:
+            ciphertext += plaintext[i]
     return ciphertext
 
 
@@ -23,6 +52,34 @@ def decrypt_vigenere(ciphertext: str, keyword: str) -> str:
     >>> decrypt_vigenere("LXFOPVEFRNHR", "LEMON")
     'ATTACKATDAWN'
     """
+
+    if len(ciphertext) > len(keyword):
+        diff = len(ciphertext) - len(keyword)
+        for i in range(diff):
+            keyword += keyword[i]
+    nums = []
     plaintext = ""
-    # PUT YOUR CODE HERE
-    return plaintext
+    for i in range(len(ciphertext)):
+        if keyword[i].isalpha():
+            if keyword[i].islower():
+                nums.append((ord(keyword[i]) - ord("a")) % 26)
+            else:
+                nums.append((ord(keyword[i]) - ord("A")) % 26)
+        else:
+            nums.append(0)
+
+    for i in range(len(nums)):
+        if ciphertext[i].isalpha():
+            if ciphertext[i].islower():
+                if ord(ciphertext[i]) - nums[i] >= ord("a"):
+                    plaintext += chr(ord(ciphertext[i]) - nums[i])
+                else:
+                    plaintext += chr(ord(ciphertext[i]) - nums[i] + 26)
+            else:
+                if ord(ciphertext[i]) - nums[i] >= ord("A"):
+                    plaintext += chr(ord(ciphertext[i]) - nums[i])
+                else:
+                    plaintext += chr(ord(ciphertext[i]) - nums[i] + 26)
+        else:
+            plaintext += ciphertext[i]
+    return plaintext