Encryption – You can not understand a particular cryptographic-based symmetric algorithm?

I'm working on a cryptographically based symmetric algorithm. But before that is, I need to create software code for a previously suggested algorithm in Java. The algorithm I need to solve looks like this:

A. encryption process

The proposed encryption algorithm works in the following steps:

  1. Read the input text.
  2. Now insert the key in front of the text.
  3. Find the ASCII code of each text and convert it to binary.
  4. Find out A complement of the previous binary data.
  5. Convert binary data and determine the decimal value.
  6. The decimal value is now divided by 4 and finds the corresponding ASCII code of the result division and sets it as a character with reminder.
  7. Now merge the result with the rest to get the ciphertext.
  8. Finally, the cipher got the encrypted text back.

&&

B. Decryption process

The proposed decryption algorithm works in the following steps:

  1. Read the ciphertext.
  2. Now divide the two-digit ciphertext into a single digit.
  3. Multiply the first digit by 4 and add the second digit to the multiplication result.
  4. Convert the result of the above steps into a binary equivalent.
  5. Take the one's complement of the binary equivalent of the result.
  6. Find the decimal value of the previous value obtained by the complement.

< Graphical representation of encryption

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For more information, please visit this link. A new and more authentic cryptographic approach to securing short messages

If any of you can cite the solutions of this algorithm. Could be Mathematically or Java Solutions. If I can know it Mathematically Solutions then I should be able to make Java implementation my own. Actually, I am a Java expert, but have little knowledge of algorithms.

Please help me if anyone can. So that I can make my own algorithm.