Simple Cryptography Algorithms

Thanks to TutorialsPoint for the great Tutorial/Course ! I found it so informative and useful that it inspired me to create this part.

Reverse Cipher Algorithm

The reverse cipher algorithm is a very simple encryption algorithm that encrypts a message by reversing the order of the characters. To decrypt the message, simply reverse the order of the characters again.

Here is a Python code implementation of the reverse cipher algorithm:

def reverse_cipher_algorithm(cipher_text):
  """Reverses a cipher algorithm.
  Args:
    cipher_text: The cipher text to be reversed.
  Returns:
    The original text.
  """
  reversed_text = ""
  for i in range(len(cipher_text) - 1, -1, -1):
    reversed_text += cipher_text[i]
  return reversed_text

The reverse cipher algorithm is a very weak encryption algorithm, and it should not be used to encrypt sensitive data. However, it can be a fun and educational exercise to learn about cryptography.

Caesar Cipher Algorithm

The Caesar cipher algorithm is a simple encryption algorithm that shifts each letter of a message by a certain number of positions in the alphabet. The number of positions that the letters are shifted is called the key.

To encrypt a message using the Caesar cipher algorithm, simply add the key to each letter of the message. If the sum is greater than 25, subtract 26 until the sum is between 0 and 25.

To decrypt a message encrypted with the Caesar cipher algorithm, simply subtract the key from each letter of the message. If the sum is less than 0, add 26 until the sum is between 0 and 25.

Here is a Python code implementation of the Caesar cipher algorithm:

def caesar_cipher_algorithm(plain_text, key):
  """Encrypts or decrypts a message using the Caesar cipher algorithm.
  Args:
    plain_text: The plain text to be encrypted or decrypted.
    key: The key to be used for encryption or decryption.
  Returns:
    The encrypted or decrypted text.
  """
  cipher_text = ""
  for letter in plain_text:
    if letter.isalpha():
      shifted_letter = ord(letter) + key
      if shifted_letter > 122:
        shifted_letter -= 26
      elif shifted_letter < 97:
        shifted_letter += 26
      cipher_text += chr(shifted_letter)
    else:
      cipher_text += letter
  return cipher_text

The Caesar cipher algorithm is a very weak encryption algorithm, and it should not be used to encrypt sensitive data. However, it can be a fun and educational exercise to learn about cryptography.

ROT13 Algorithm

ROT13 is a simple letter substitution cipher that replaces each letter with the letter 13 places after it in the alphabet. For example, "A" becomes "N", "B" becomes "O", and so on.

ROT13 is often used to obscure spoilers or offensive content in online forums and discussion boards. It is also sometimes used to encrypt passwords, but this is not recommended as ROT13 is a very weak encryption algorithm.

Here is a Python code implementation of the ROT13 algorithm:

def rot13_algorithm(plain_text):
  """Encrypts or decrypts a message using the ROT13 algorithm.
  Args:
    plain_text: The plain text to be encrypted or decrypted.
  Returns:
    The encrypted or decrypted text.
  """
  rot13_text = ""
  for letter in plain_text:
    if letter.isalpha():
      shifted_letter = ord(letter) + 13
      if shifted_letter > 122:
        shifted_letter -= 26
      elif shifted_letter < 97:
        shifted_letter += 26
      rot13_text += chr(shifted_letter)
    else:
      rot13_text += letter
  return rot13_text

ROT13 is a very weak encryption algorithm, and it should not be used to encrypt sensitive data. However, it can be a fun and educational exercise to learn about cryptography.

Transposition Cipher Algorithm

A transposition cipher is a type of encryption that works by rearranging the letters of a message in a different order. This can be done using a variety of different methods, such as:

• Columnar transposition: The message is written out in columns and then the columns are rearranged in a different order.

• Row transposition: The message is written out in rows and then the rows are rearranged in a different order.

• Double transposition: The message is transposed twice, using a different method each time.

Transposition ciphers can be more difficult to break than substitution ciphers, but they are also more difficult to use. This is because the sender and receiver need to agree on the transposition key in order to encrypt and decrypt messages.

Here is a Python code implementation of the columnar transposition cipher algorithm:

def columnar_transposition_algorithm(plain_text, key):
  """Encrypts or decrypts a message using the columnar transposition 
  cipher algorithm.
  Args:
    plain_text: The plain text to be encrypted or decrypted.
    key: The key to be used for encryption or decryption.
  Returns:
    The encrypted or decrypted text.
  """
  cipher_text = ""
  columns = []
  for i in range(len(key)):
    columns.append([])
  for i in range(len(plain_text)):
    columns[i % len(key)].append(plain_text[i])
  for column in columns:
    cipher_text += "".join(column)
  return cipher_text

Transposition ciphers can be a fun and educational way to learn about cryptography. However, they should not be used to encrypt sensitive data, as they are not as secure as other encryption algorithms.

Other Algorithms

• Atbash cipher: The Atbash cipher is a simple substitution cipher that reverses the alphabet.

• Vigenère cipher: The Vigenère cipher is a polyalphabetic substitution cipher that uses multiple cipher alphabets to encrypt a message.

• Columnar transposition cipher: The columnar transposition cipher is a transposition cipher that rearranges the columns of a message in a different order.

• Row transposition cipher: The row transposition cipher is a transposition cipher that rearranges the rows of a message in a different order.

• Rail fence cipher: The rail fence cipher is a transposition cipher that zigzags the letters of a message across multiple rows.

• Playfair cipher: The Playfair cipher is a substitution cipher that uses a 5x5 grid of letters to encrypt a message.

• One-time pad: The one-time pad is a perfect encryption algorithm that is unbreakable if used correctly. However, it is also very impractical to use, as it requires a one-time-use key that is as long as the message being encrypted.

• Vernam cipher: The Vernam cipher is a symmetric encryption algorithm that uses a key to encrypt a message. The key is the same length as the message being encrypted, and it is XORed with the message to produce the ciphertext.