diff --git a/src/main/java/com/mattrixwv/CipherStreamJava/monoSubstitution/Porta.java b/src/main/java/com/mattrixwv/CipherStreamJava/monoSubstitution/Porta.java
new file mode 100644
index 0000000..958ce0c
--- /dev/null
+++ b/src/main/java/com/mattrixwv/CipherStreamJava/monoSubstitution/Porta.java
@@ -0,0 +1,207 @@
+//CipherStreamJava/src/main/java/com/mattrixwv/CipherStreamJava/monoSubstitution/Porta.java
+//Mattrixwv
+// Created: 02-28-22
+//Modified: 02-28-22
+package com.mattrixwv.CipherStreamJava.monoSubstitution;
+
+
+import com.mattrixwv.CipherStreamJava.exceptions.InvalidInputException;
+import com.mattrixwv.CipherStreamJava.exceptions.InvalidKeywordException;
+
+
+public class Porta{
+	private static final String[] tableau = {
+		"NOPQRSTUVWXYZABCDEFGHIJKLM",	//A-B
+		"OPQRSTUVWXYZNMABCDEFGHIJKL",	//C-D
+		"PQRSTUVWXYZNOLMABCDEFGHIJK",	//E-F
+		"QRSTUVWXYZNOPKLMABCDEFGHIJ",	//G-H
+		"RSTUVWXYZNOPQJKLMABCDEFGHI",	//I-J
+		"STUVWXYZNOPQRIJKLMABCDEFGH",	//K-L
+		"TUVWXYZNOPQRSHIJKLMABCDEFG",	//M-N
+		"UVWXYZNOPQRSTGHIJKLMABCDEF",	//O-P
+		"VWXYZNOPQRSTUFGHIJKLMABCDE",	//Q-R
+		"WXYZNOPQRSTUVEFGHIJKLMABCD",	//S-T
+		"XYZNOPQRSTUVWDEFGHIJKLMABC",	//U-V
+		"YZNOPQRSTUVWXCDEFGHIJKLMAB",	//W-X
+		"ZNOPQRSTUVWXYBCDEFGHIJKLMA"	//Y-Z
+	};
+
+	private String inputString;
+	private String outputString;
+	private String keyword;
+	private boolean preserveCapitals;
+	private boolean preserveWhitespace;
+	private boolean preserveSymbols;
+
+	private void setKeyword(String keyword) throws InvalidKeywordException{
+		//Make sure the keyword isn't null
+		if(keyword == null){
+			throw new InvalidKeywordException("Keyword cannot be null");
+		}
+
+		//Convert all letters to uppercase
+		keyword = keyword.toUpperCase();
+		//Remove all characters except capital letters and save the string
+		keyword = keyword.replaceAll("[^A-Z]", "");
+		this.keyword = keyword;
+
+		//If after eliminating all ususable characters the keyword is empty throw an exception
+		if(this.keyword.isBlank() || (this.keyword.length() < 2)){
+			throw new InvalidKeywordException("Keyword must contain at least 2 letters");
+		}
+	}
+	private void setInputString(String inputString) throws InvalidInputException{
+		//Ensure the input isn't null
+		if(inputString == null){
+			throw new InvalidInputException("Input cannot be null");
+		}
+
+		//Apply removal options
+		if(!preserveCapitals){
+			inputString = inputString.toUpperCase();
+		}
+		if(!preserveWhitespace){
+			inputString = inputString.replaceAll("\\s", "");
+		}
+		if(!preserveSymbols){
+			inputString = inputString.replaceAll("[^a-zA-Z\\s]", "");
+		}
+
+		//Save the string
+		this.inputString = inputString;
+
+		//Ensure the string isn't blank
+		if(this.inputString.isBlank()){
+			throw new InvalidInputException("Input must contain at least 1 letter");
+		}
+	}
+	private char getReplacer(int keywordCnt, char letter){
+		char keyLetter = keyword.charAt(keywordCnt % keyword.length());
+		int tableauColumn = (Character.toUpperCase(letter) - 'A');
+		char replacer = '\0';
+
+		switch(keyLetter){
+			case 'A':
+			case 'B':
+				replacer = tableau[0].charAt(tableauColumn); break;
+			case 'C':
+			case 'D':
+				replacer = tableau[1].charAt(tableauColumn); break;
+			case 'E':
+			case 'F':
+				replacer = tableau[2].charAt(tableauColumn); break;
+			case 'G':
+			case 'H':
+				replacer = tableau[3].charAt(tableauColumn); break;
+			case 'I':
+			case 'J':
+				replacer = tableau[4].charAt(tableauColumn); break;
+			case 'K':
+			case 'L':
+				replacer = tableau[5].charAt(tableauColumn); break;
+			case 'M':
+			case 'N':
+				replacer = tableau[6].charAt(tableauColumn); break;
+			case 'O':
+			case 'P':
+				replacer = tableau[7].charAt(tableauColumn); break;
+			case 'Q':
+			case 'R':
+				replacer = tableau[8].charAt(tableauColumn); break;
+			case 'S':
+			case 'T':
+				replacer = tableau[9].charAt(tableauColumn); break;
+			case 'U':
+			case 'V':
+				replacer = tableau[10].charAt(tableauColumn); break;
+			case 'W':
+			case 'X':
+				replacer = tableau[11].charAt(tableauColumn); break;
+			case 'Y':
+			case 'Z':
+				replacer = tableau[12].charAt(tableauColumn); break;
+			default:
+				replacer = letter;
+		}
+
+		return replacer;
+	}
+	private void encode(){
+		StringBuilder output = new StringBuilder();
+
+		//Step through every character in the inputString and advance it the correct amount according to the keyword and tableau
+		int keywordCnt = 0;
+		for(char letter : inputString.toCharArray()){
+			//If the character is a letter replace with the corresponding character from the tableau
+			if(Character.isUpperCase(letter)){
+				letter = Character.toUpperCase(getReplacer(keywordCnt, letter));
+				++keywordCnt;
+			}
+			else if(Character.isLowerCase(letter)){
+				letter = Character.toLowerCase(getReplacer(keywordCnt, letter));
+				++keywordCnt;
+			}
+
+			//Add the current character to the output
+			output.append(letter);
+		}
+
+		//Save the output
+		outputString = output.toString();
+	}
+	private void decode(){
+		//Decoding is the same as encoding
+		encode();
+	}
+
+
+	//Constructor
+	public Porta(){
+		preserveCapitals = false;
+		preserveWhitespace = false;
+		preserveSymbols = false;
+		reset();
+	}
+	public Porta(boolean preserveCapitals, boolean preserveWhitespace, boolean preserveSymbols){
+		this.preserveCapitals = preserveCapitals;
+		this.preserveWhitespace = preserveWhitespace;
+		this.preserveSymbols = preserveSymbols;
+		reset();
+	}
+
+	public String encode(String keyword, String inputString) throws InvalidKeywordException, InvalidInputException{
+		//Set the parameters
+		reset();
+		setKeyword(keyword);
+		setInputString(inputString);
+
+		//Encode and return the message
+		encode();
+		return outputString;
+	}
+	public String decode(String keyword, String inputString) throws InvalidKeywordException, InvalidInputException{
+		//Set the parameters
+		reset();
+		setKeyword(keyword);
+		setInputString(inputString);
+
+		//Decode and return the message
+		decode();
+		return outputString;
+	}
+
+	public String getInputString(){
+		return inputString;
+	}
+	public String getOutputString(){
+		return outputString;
+	}
+	public String getKeyword(){
+		return keyword;
+	}
+	public void reset(){
+		inputString = "";
+		outputString = "";
+		keyword = "";
+	}
+}