Chapter 21, Problem 1PP

Program Plan Intro

Random monoalphabet cipher

Program plan:

• In the file “MonoalphabetCipher.java”, import necessary packages and create a class “MonoalphabetCipher”,
  • Declare the arrays.
  • Define the constructor to initialize the arrays.
  • Define the method “contains()” that returns true, if there is a specified value otherwise returns false.
  • Define the method “processStream()” to process the contents of a stream.
  • Define the method “process()” to process a byte.
  • Define the method “encryptStream()” to encrypts the contents of a stream.
  • Define the method “decryptStream()” to decrypt the contents of a file.
• In the file “Encryptor.java”, import necessary packages and create a class “Encryptor”,
  • Define the method “main()”,
    • Initialize the necessary variables.
    • Execute “try” statement,
      • Execute “while” loop till the length of the argument,
        • If the argument id “d”,
        • • Set the Boolean value to true.
        • Otherwise check if the argument is “k”,
        • • Increment the value by 1.
          • Check the condition,
            • If it is true, set the key.
        • Otherwise, if the input file is null,
        • • Get the input file.
        • Otherwise, if the output file is null,
        • • Get the output file.
      • If either the input or output or key is null,
        • Print the string.
      • Otherwise,
        • Create the input stream.
        • Create the output stream.
        • Create an object.
        • If decrypt,
        • • Call the method “decryptStream()”.
        • Otherwise,
        • • Call the method “encryptStream()”.
        • Close the input and output file.
    • Catch if exception occur,
      • Handle the exception.