From 77f3cb07662702a1d66a1774e9f99bc9bbc8a14c Mon Sep 17 00:00:00 2001
From: Rovers11 <spandanmukherjeegithub@gmail.com>
Date: Fri, 11 Oct 2024 11:33:19 +0530
Subject: [PATCH 1/2] Add Gronsfeld cipher implementation

---
 ciphers/gronsfeld.py | 63 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 ciphers/gronsfeld.py

diff --git a/ciphers/gronsfeld.py b/ciphers/gronsfeld.py
new file mode 100644
index 000000000000..0c9cb45ed53a
--- /dev/null
+++ b/ciphers/gronsfeld.py
@@ -0,0 +1,63 @@
+def gronsfeld_encrypt(plaintext, key):
+    """
+    Encrypts a plaintext using the Gronsfeld cipher.
+    
+    Parameters:
+    plaintext (str): The message to be encrypted.
+    key (str): A numeric key used for encryption (e.g., "31415").
+    
+    Returns:
+    str: The encrypted message.
+    """
+    ciphertext = ""
+    key = [int(k) for k in key]
+    key_length = len(key)
+    
+    for i, letter in enumerate(plaintext):
+        if letter.isalpha():
+            shift = key[i % key_length]
+            base = ord('A') if letter.isupper() else ord('a')
+            # Shift and wrap around the alphabet
+            ciphertext += chr((ord(letter) - base + shift) % 26 + base)
+        else:
+            ciphertext += letter
+    
+    return ciphertext
+
+
+def gronsfeld_decrypt(ciphertext, key):
+    """
+    Decrypts a ciphertext using the Gronsfeld cipher.
+    
+    Parameters:
+    ciphertext (str): The message to be decrypted.
+    key (str): A numeric key used for decryption (e.g., "31415").
+    
+    Returns:
+    str: The decrypted message.
+    """
+    plaintext = ""
+    key = [int(k) for k in key]
+    key_length = len(key)
+    
+    for i, letter in enumerate(ciphertext):
+        if letter.isalpha():
+            shift = key[i % key_length]
+            base = ord('A') if letter.isupper() else ord('a')
+            # Reverse the shift to decrypt
+            plaintext += chr((ord(letter) - base - shift) % 26 + base)
+        else:
+            plaintext += letter
+    
+    return plaintext
+
+
+# Example usage:
+plaintext = input("Enter a message to encrypt: ")
+key = input("Enter a key (e.g., 31415): ")
+
+encrypted_message = gronsfeld_encrypt(plaintext, key)
+print(f"Encrypted: {encrypted_message}")
+
+decrypted_message = gronsfeld_decrypt(encrypted_message, key)
+print(f"Decrypted: {decrypted_message}")

From 22378d16b10723f58345f2865f7cdf67f6dee9ac Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Fri, 11 Oct 2024 06:07:34 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 ciphers/gronsfeld.py | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/ciphers/gronsfeld.py b/ciphers/gronsfeld.py
index 0c9cb45ed53a..e73936835727 100644
--- a/ciphers/gronsfeld.py
+++ b/ciphers/gronsfeld.py
@@ -1,54 +1,54 @@
 def gronsfeld_encrypt(plaintext, key):
     """
     Encrypts a plaintext using the Gronsfeld cipher.
-    
+
     Parameters:
     plaintext (str): The message to be encrypted.
     key (str): A numeric key used for encryption (e.g., "31415").
-    
+
     Returns:
     str: The encrypted message.
     """
     ciphertext = ""
     key = [int(k) for k in key]
     key_length = len(key)
-    
+
     for i, letter in enumerate(plaintext):
         if letter.isalpha():
             shift = key[i % key_length]
-            base = ord('A') if letter.isupper() else ord('a')
+            base = ord("A") if letter.isupper() else ord("a")
             # Shift and wrap around the alphabet
             ciphertext += chr((ord(letter) - base + shift) % 26 + base)
         else:
             ciphertext += letter
-    
+
     return ciphertext
 
 
 def gronsfeld_decrypt(ciphertext, key):
     """
     Decrypts a ciphertext using the Gronsfeld cipher.
-    
+
     Parameters:
     ciphertext (str): The message to be decrypted.
     key (str): A numeric key used for decryption (e.g., "31415").
-    
+
     Returns:
     str: The decrypted message.
     """
     plaintext = ""
     key = [int(k) for k in key]
     key_length = len(key)
-    
+
     for i, letter in enumerate(ciphertext):
         if letter.isalpha():
             shift = key[i % key_length]
-            base = ord('A') if letter.isupper() else ord('a')
+            base = ord("A") if letter.isupper() else ord("a")
             # Reverse the shift to decrypt
             plaintext += chr((ord(letter) - base - shift) % 26 + base)
         else:
             plaintext += letter
-    
+
     return plaintext