diff --git a/19_KhushaliPanchal/Practicals/AES.java b/19_KhushaliPanchal/Practicals/AES.java
new file mode 100644
index 0000000..444babd
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/AES.java
@@ -0,0 +1,30 @@
+import javax.crypto.*;
+import javax.crypto.spec.*;
+import java.util.Scanner;
+class AES{
+	private byte[] key;
+	AES(){
+		key="kHFlksfddsaKHBDS".getBytes();
+	}
+	private byte[] encrypt(String plainText) throws Exception{
+		SecretKeySpec sKey = new SecretKeySpec(key,"AES");
+		Cipher cipher = Cipher.getInstance("AES");
+		cipher.init(Cipher.ENCRYPT_MODE,sKey);
+		return cipher.doFinal(plainText.getBytes());
+	}
+	private byte[] decrypt(String cipherText) throws Exception{
+		SecretKeySpec sKey=new SecretKeySpec(key,"AES");
+		Cipher cipher = Cipher.getInstance("AES");
+		cipher.init(Cipher.DECRYPT_MODE,sKey);
+		return cipher.doFinal(cipherText.getBytes());
+	}
+	public static void main(String args[]) throws Exception{
+		Scanner sc=new Scanner(System.in);
+		System.out.print("Enter Plain Text : ");
+		String plainText=sc.nextLine();
+		AES aes=new AES();
+		String cipherText=new String(aes.encrypt(plainText));
+		System.out.println("Encrypted Text : " + cipherText);
+		System.out.println("Decrypted Text : " + new String(aes.decrypt(cipherText)));
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/Ceaser_Cipher.java b/19_KhushaliPanchal/Practicals/Ceaser_Cipher.java
new file mode 100644
index 0000000..6ecf0c7
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/Ceaser_Cipher.java
@@ -0,0 +1,84 @@
+ import java.util.*;
+public class Ceaser_Cipher
+{
+	public static String encryption(String msg, int shift)
+	{
+		String encrypted="";
+		char ch;
+		for(int i=0;i<msg.length();i++)
+		{
+			ch = msg.charAt(i);
+			if(ch > 'a' && ch < 'z')
+			{
+				ch = (char)(ch + shift);
+				if(ch > 'z')
+				{
+					ch = (char)(ch - 'z' + 'a'-1);
+				}
+				encrypted= encrypted + ch;
+			}
+			else if(ch >= 'A' && ch <= 'Z')
+			{
+				ch = (char)(ch + shift);
+				if(ch > 'Z')
+				{
+					ch = (char)(ch - 'Z' + 'A' - 1);
+				}
+				encrypted = encrypted + ch;
+			}
+			else
+			{
+				encrypted = encrypted + ch;
+			}
+		}
+		return encrypted;
+	}
+	
+	public static String decryption(String encrypted,int shift)
+	{
+		String decrypted="";
+		char ch;
+		for(int i=0;i<encrypted.length();i++)
+		{
+			ch = encrypted.charAt(i);
+			if(ch > 'a' && ch < 'z')
+			{
+				ch = (char)(ch - shift);
+				if(ch > 'z')
+				{
+					ch = (char)(ch + 'z' - 'a'+1);
+				}
+				decrypted= decrypted + ch;
+			}
+			else if(ch >= 'A' && ch <= 'Z')
+			{
+				ch = (char)(ch - shift);
+				if(ch > 'Z')
+				{
+					ch = (char)(ch + 'Z' - 'A' + 1);
+				}
+				decrypted = decrypted + ch;
+			}
+			else
+			{
+				decrypted = decrypted + ch;
+			}
+		}
+		return decrypted;
+	}
+	public static void main(String args[])
+	{
+		String msg,encrypted="",decrypted="";
+		int shift = 3;
+		Scanner sc = new Scanner(System.in);
+		
+		System.out.println("Enter text in plain text.");
+		msg = sc.next();
+		
+		encrypted = encryption(msg,shift);
+		System.out.println("Encrypted Message: " + encrypted);
+		
+		decrypted=decryption(encrypted,shift);
+		System.out.println("Decrypted Message: " + decrypted);
+	}
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/DES.java b/19_KhushaliPanchal/Practicals/DES.java
new file mode 100644
index 0000000..d9159c9
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/DES.java
@@ -0,0 +1,71 @@
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.Cipher;
+import javax.crypto.KeyGenerator;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
+import java.util.*;
+import java.util.Base64;
+import java.util.Base64;;
+
+public class DES {
+
+	private static Cipher ecipher;
+	private static Cipher dcipher;
+
+	private static SecretKey key;
+
+	public static void main(String[] args) {
+		Scanner sc = new Scanner(System.in);
+
+		try {
+			key = KeyGenerator.getInstance("DES").generateKey();
+
+			ecipher = Cipher.getInstance("DES");
+			dcipher = Cipher.getInstance("DES");
+			
+			ecipher.init(Cipher.ENCRYPT_MODE, key);
+			dcipher.init(Cipher.DECRYPT_MODE, key);
+			System.out.println("Enter Plain Text:");
+			String text = sc.nextLine();
+			String encrypted = encrypt(text);
+			String decrypted = decrypt(encrypted);
+			System.out.println("Decrypted: " + decrypted);
+
+		}
+		catch (Exception e) {
+			e.printStackTrace();
+			return;
+		}
+		
+
+	}
+
+	public static String encrypt(String str) 
+	{
+		try {
+		byte[] utf8 = str.getBytes("UTF8");
+		byte[] enc = ecipher.doFinal(utf8);
+		enc = Base64.getEncoder().encode(enc);
+		String str1 = Base64.getEncoder().encodeToString(enc);
+		System.out.println("Encrypted String.\n" + str1);
+		return new String(enc);
+		}catch (Exception e) {e.printStackTrace();}
+
+		return null;
+
+    }
+
+	public static String decrypt(String str) 
+	{
+		try {
+			byte[] dec = Base64.getDecoder().decode(str.getBytes());
+			byte[] utf8 = dcipher.doFinal(dec);
+
+			return new String(utf8, "UTF8");
+			}catch (Exception e) {e.printStackTrace();}
+			return null;
+	}
+
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/Firewall/ClientFirewall.java b/19_KhushaliPanchal/Practicals/Firewall/ClientFirewall.java
new file mode 100644
index 0000000..7299c73
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/Firewall/ClientFirewall.java
@@ -0,0 +1,19 @@
+package Assign2.que3;
+import java.util.*;
+import java.io.*;
+import java.net.*;
+public class ClientFirewall
+{
+	public static void main(String args[]) throws Exception
+	{
+		Scanner sc = new Scanner(System.in);
+		Socket socket = new Socket("127.0.0.1",5000);
+		DataOutputStream out = new DataOutputStream(socket.getOutputStream());
+		String number = "";
+		System.out.println("Enter String:");
+		number = sc.nextLine();
+		out.writeBytes(number + "\n");
+		System.out.println(number + " sent to forwerder:");
+		socket.close();
+	}
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/Firewall/Forwarder.java b/19_KhushaliPanchal/Practicals/Firewall/Forwarder.java
new file mode 100644
index 0000000..5243f4b
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/Firewall/Forwarder.java
@@ -0,0 +1,37 @@
+package Assign2.que3;
+import java.io.*;
+import java.net.*;
+import java.util.*;
+
+public class Forwarder
+{
+	public static void main(String args[])throws Exception
+	{
+		int number = 0;
+		String msg = null;
+		ServerSocket server = new ServerSocket(5000);
+		Socket socket = server.accept();
+		BufferedReader input  = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+		String str = null;
+		str = input.readLine();
+		System.out.println("Recieved From Client:");
+		System.out.println(str);
+		
+		server.close();
+		socket.close();
+		Socket socket1 = new Socket("127.0.0.1",4000);
+		DataOutputStream out = new DataOutputStream(socket1.getOutputStream());
+		if(!str.contains("Terrorist"))
+		{
+			System.out.println("This text is safe");
+			out.writeBytes(str);
+		}
+		else
+		{
+			System.out.println("This Text cannot forwarded");
+		}
+		
+		socket1.close();
+	}
+
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/Firewall/ServerFireWall.java b/19_KhushaliPanchal/Practicals/Firewall/ServerFireWall.java
new file mode 100644
index 0000000..9022cc4
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/Firewall/ServerFireWall.java
@@ -0,0 +1,23 @@
+package Assign2.que3;
+import java.io.*;
+import java.util.*;
+import java.net.*;
+
+public class ServerFireWall
+{
+	public static void main(String args[])throws Exception
+	{
+		int num = 0,temp;
+		ServerSocket server = new ServerSocket(4000);
+		Socket socket = server.accept();
+		BufferedReader input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+		String received = null;
+		received = input.readLine();
+		num = Integer.parseInt(received);
+		System.out.println("Successfully Recieved");
+		System.out.println(num);
+		server.close();
+		socket.close();
+		
+	}
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/MD5.java b/19_KhushaliPanchal/Practicals/MD5.java
new file mode 100644
index 0000000..1b3541d
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/MD5.java
@@ -0,0 +1,21 @@
+import java.util.Scanner;
+import java.math.*;
+import java.security.*;
+class MD5{
+	private String doEncryption(String text) throws Exception{
+		MessageDigest md=MessageDigest.getInstance("MD5");
+		byte[] msg=md.digest(text.getBytes());
+		BigInteger bigInt=new BigInteger(1,msg);
+		String hashValue=bigInt.toString(16);
+		while(hashValue.length()<32)
+			hashValue+=0+hashValue;
+		return hashValue;
+	}
+	public static void main(String args[]) throws Exception{
+		MD5 MD5=new MD5();
+		Scanner sc=new Scanner(System.in);
+		System.out.print("\nEnter Message: ");
+		String text=sc.nextLine();
+		System.out.print("\nHash Text: " + MD5.doEncryption(text));
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/NAT/NAT.java b/19_KhushaliPanchal/Practicals/NAT/NAT.java
new file mode 100644
index 0000000..67f35e1
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/NAT/NAT.java
@@ -0,0 +1,53 @@
+//package Assign2.que4;
+import java.util.*;
+import java.io.*;
+import java.net.*;
+
+public class NAT
+{
+	public static void main(String args[]) throws IOException
+	{
+		ServerSocket ds=new ServerSocket(1233);
+		Socket sk=ds.accept();
+		BufferedReader br=new BufferedReader(new InputStreamReader(sk.getInputStream()));
+		while(true)
+		{			
+			String s;
+			s=br.readLine();			
+			if(s.equalsIgnoreCase("exit"))
+			{
+				System.out.println("Exiting!");				
+				Socket sk1=new Socket("127.0.0.1",1234);
+				Socket sk2=new Socket("127.0.0.1",1235);				
+				DataOutputStream dos1=new DataOutputStream(sk1.getOutputStream());
+				DataOutputStream dos2=new DataOutputStream(sk2.getOutputStream());
+				dos1.writeBytes(s+"\n");
+				dos2.writeBytes(s+"\n");
+				break;
+			}
+			else
+			{
+				System.out.println("Number successfully received by Firewall: "+s);
+				int pn=checkString(s);
+				Socket sk1=new Socket("127.0.0.1",pn);
+				DataOutputStream dos=new DataOutputStream(sk1.getOutputStream());
+				dos.writeBytes(s+"\n");
+			}
+		}
+	}
+	
+	public static int checkString(String s)
+	{
+		int n=Integer.parseInt(s);
+		if(n%2==0)
+		{
+			System.out.println(n+" is Even Number and forwarded to 1234");
+			return 1234;
+		}
+		else
+		{
+			System.out.println(n+" is ODD Number and forwarded to 1235");
+			return 1235;
+		}
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/NAT/NATClient.java b/19_KhushaliPanchal/Practicals/NAT/NATClient.java
new file mode 100644
index 0000000..bc5a718
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/NAT/NATClient.java
@@ -0,0 +1,28 @@
+//package Assign2.que4;
+import java.util.*;
+import java.io.*;
+import java.net.*;
+
+public class NATClient
+{
+	public static void main(String args[]) throws IOException
+	{
+		Scanner sc=new Scanner(System.in);
+		Socket ds=new Socket("127.0.0.1",1233);
+		DataOutputStream dos=new DataOutputStream(ds.getOutputStream());
+		String s;
+		while(true)
+		{
+			s="";
+			System.out.println("Enter Number: ");
+			s=sc.nextLine();
+			dos.writeBytes(s+"\n");
+			if(s.equalsIgnoreCase("exit"))
+			{
+				System.out.println("Exiting!");
+				break;
+			}
+			System.out.println("String: "+s+" sent Successfully!");
+		}
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/NAT/NATEven.java b/19_KhushaliPanchal/Practicals/NAT/NATEven.java
new file mode 100644
index 0000000..80e2e3e
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/NAT/NATEven.java
@@ -0,0 +1,25 @@
+import java.util.*;
+//package Assign2.que4;
+import java.io.*;
+import java.net.*;
+
+public class NATEven
+{
+	public static void main(String args[]) throws IOException
+	{
+			ServerSocket ds=new ServerSocket(1234);	
+		while(true)
+		{
+			String es="";
+			Socket sk=ds.accept();
+			BufferedReader br=new BufferedReader(new InputStreamReader(sk.getInputStream()));
+			es=br.readLine();
+			if(es.equalsIgnoreCase("exit"))
+			{
+				System.out.println("Exiting!");
+				break;
+			}
+			System.out.println("Even number: "+es+" successfully received!");	
+		}		
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/NAT/NATOdd.java b/19_KhushaliPanchal/Practicals/NAT/NATOdd.java
new file mode 100644
index 0000000..890d91b
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/NAT/NATOdd.java
@@ -0,0 +1,26 @@
+import java.util.*;
+//package Assign2.que4;
+
+import java.io.*;
+import java.net.*;
+
+public class NATOdd
+{
+	public static void main(String args[]) throws IOException
+	{
+			ServerSocket ds=new ServerSocket(1235);	
+		while(true)
+		{
+			String es="";
+			Socket sk=ds.accept();
+			BufferedReader br=new BufferedReader(new InputStreamReader(sk.getInputStream()));
+			es=br.readLine();
+			if(es.equalsIgnoreCase("exit"))
+			{
+				System.out.println("Exiting!");
+				break;
+			}
+			System.out.println("Odd number: "+es+" successfully received!");	
+		}		
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/P_Box.java b/19_KhushaliPanchal/Practicals/P_Box.java
new file mode 100644
index 0000000..f7580e2
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/P_Box.java
@@ -0,0 +1,39 @@
+import java.util.Scanner;
+class P_Box{
+	public String doEncryption(String s){
+		byte p[]=new byte[8];
+		byte pTemp[]=new byte[8];
+		pTemp=s.getBytes();
+		p[0]=pTemp[4];
+		p[1]=pTemp[0];
+		p[2]=pTemp[5];
+		p[3]=pTemp[7];
+		p[4]=pTemp[1];
+		p[5]=pTemp[3];
+		p[6]=pTemp[2];
+		p[7]=pTemp[6];
+		return(new String(p));
+	}
+	public String doDecryption(String s){
+		byte p[]=new byte[8];
+		byte pTemp[]=new byte[8];
+		pTemp=s.getBytes();
+		p[0]=pTemp[1];
+		p[1]=pTemp[4];
+		p[2]=pTemp[6];
+		p[3]=pTemp[5];
+		p[4]=pTemp[0];
+		p[5]=pTemp[2];
+		p[6]=pTemp[7];
+		p[7]=pTemp[3];
+		return(new String(p));
+	}
+	public static void main(String args[]){
+		Scanner sc=new Scanner(System.in);
+		System.out.print("\nEnterString(Only 8 Characters) : ");
+		String plaintext=sc.nextLine();
+		P_Box p_box=new P_Box();
+		System.out.println("Encrypted Text : " + p_box.doEncryption(plaintext));
+		System.out.println("Decrypted Text : " + p_box.doDecryption(p_box.doEncryption(plaintext)));
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/PasswordEncryption/Client.java b/19_KhushaliPanchal/Practicals/PasswordEncryption/Client.java
new file mode 100644
index 0000000..658a17b
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/PasswordEncryption/Client.java
@@ -0,0 +1,51 @@
+package Assign2.que1;
+import java.net.*;
+import java.io.*;
+import java.util.Scanner;
+class Client{
+	public static void main(String args[]) throws Exception{
+		Socket s=new Socket("127.0.0.1",1234);
+		
+		Scanner sc=new Scanner(System.in);
+		System.out.println("Enter Password : ");
+		String msg=sc.nextLine();
+		String encrypted = encryption(msg);
+		
+		DataOutputStream out=new DataOutputStream(s.getOutputStream());
+		out.writeUTF(encrypted);
+		s.close();
+	}
+	public static String encryption(String msg)
+	{
+		String encrypted="";
+		char ch;
+		for(int i=0;i<msg.length();i++)
+		{
+			ch = msg.charAt(i);
+			if(ch > 'a' && ch < 'z')
+			{
+				ch = (char)(ch + 3);
+				if(ch > 'z')
+				{
+					ch = (char)(ch - 'z' + 'a'-1);
+				}
+				encrypted= encrypted + ch;
+			}
+			else if(ch >= 'A' && ch <= 'Z')
+			{
+				ch = (char)(ch + 3);
+				if(ch > 'Z')
+				{
+					ch = (char)(ch - 'Z' + 'A' - 1);
+				}
+				encrypted = encrypted + ch;
+			}
+			else
+			{
+				encrypted = encrypted + ch;
+			}
+		}
+		return encrypted;
+	}
+	
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/PasswordEncryption/Server.java b/19_KhushaliPanchal/Practicals/PasswordEncryption/Server.java
new file mode 100644
index 0000000..7e74016
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/PasswordEncryption/Server.java
@@ -0,0 +1,70 @@
+package Assign2.que1;
+import java.io.*;
+import java.net.*;
+import java.util.Scanner;
+import java.sql.*;
+class Server{
+	public static void main(String args[]) throws Exception{
+		ServerSocket ss=new ServerSocket(1234);
+		Socket s=ss.accept();
+		
+		System.out.print("From Client : ");
+		DataInputStream in=new DataInputStream(s.getInputStream());
+		String encrypted = in.readUTF();
+		String decrypted = decryption(encrypted);
+		String finalResult = checkPassword(decrypted);
+		if(finalResult.equals(decrypted))
+			System.out.println("Password Matched");
+		else
+			System.out.println("Password doesn't Matched");
+			
+		s.close();
+		ss.close();
+	}
+	public static String decryption(String encrypted)
+	{
+		String decrypted="";
+		char ch;
+		for(int i=0;i<encrypted.length();i++)
+		{
+			ch = encrypted.charAt(i);
+			if(ch > 'a' && ch < 'z')
+			{
+				ch = (char)(ch - 3);
+				if(ch > 'z')
+				{
+					ch = (char)(ch + 'z' - 'a'+1);
+				}
+				decrypted= decrypted + ch;
+			}
+			else if(ch >= 'A' && ch <= 'Z')
+			{
+				ch = (char)(ch - 3);
+				if(ch > 'Z')
+				{
+					ch = (char)(ch + 'Z' - 'A' + 1);
+				}
+				decrypted = decrypted + ch;
+			}
+			else
+			{
+				decrypted = decrypted + ch;
+			}
+		}
+		return decrypted;
+	}
+	
+	public static String checkPassword(String decrypted)throws Exception
+	{
+		String pwd = null;
+		Class.forName("com.mysql.cj.jdbc.Driver");
+		Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ns","root","");
+		Statement st = con.createStatement();
+		ResultSet rs = st.executeQuery("select * from password where pws ='" + decrypted +"';");
+		while(rs.next()){
+			pwd = rs.getString("pws");
+		}
+		return pwd;
+	}
+	
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/Que2/Client2.java b/19_KhushaliPanchal/Practicals/Que2/Client2.java
new file mode 100644
index 0000000..c207b8b
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/Que2/Client2.java
@@ -0,0 +1,51 @@
+package Assign2.que1;
+import java.net.*;
+import java.io.*;
+import java.util.Scanner;
+class Client2{
+	public static void main(String args[]) throws Exception{
+		Socket s=new Socket("127.0.0.1",1234);
+		
+		Scanner sc=new Scanner(System.in);
+		System.out.println("Enter Password : ");
+		String msg=sc.nextLine();
+		String encrypted = encryption(msg);
+		
+		DataOutputStream out=new DataOutputStream(s.getOutputStream());
+		out.writeUTF(encrypted);
+		s.close();
+	}
+	public static String encryption(String msg)
+	{
+		String encrypted="";
+		char ch;
+		for(int i=0;i<msg.length();i++)
+		{
+			ch = msg.charAt(i);
+			if(ch > 'a' && ch < 'z')
+			{
+				ch = (char)(ch + 3);
+				if(ch > 'z')
+				{
+					ch = (char)(ch - 'z' + 'a'-1);
+				}
+				encrypted= encrypted + ch;
+			}
+			else if(ch >= 'A' && ch <= 'Z')
+			{
+				ch = (char)(ch + 3);
+				if(ch > 'Z')
+				{
+					ch = (char)(ch - 'Z' + 'A' - 1);
+				}
+				encrypted = encrypted + ch;
+			}
+			else
+			{
+				encrypted = encrypted + ch;
+			}
+		}
+		return encrypted;
+	}
+	
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/Que2/Server2.java b/19_KhushaliPanchal/Practicals/Que2/Server2.java
new file mode 100644
index 0000000..10a733a
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/Que2/Server2.java
@@ -0,0 +1,81 @@
+package Assign2.que1;
+import java.io.*;
+import java.math.*;
+import java.net.*;
+import java.util.Scanner;
+import java.sql.*;
+import java.security.*;
+class Server2{
+	public static void main(String args[]) throws Exception{
+		ServerSocket ss=new ServerSocket(1234);
+		Socket s=ss.accept();
+		
+		System.out.print("From Client : ");
+		DataInputStream in=new DataInputStream(s.getInputStream());
+		String encrypted = in.readUTF();
+		String decrypted = decryption(encrypted);
+		String hashed = doHashing(decrypted);
+		String finalResult = checkPassword(decrypted);
+		if(finalResult.equals(decrypted))
+			System.out.println("Password Matched");
+		else
+			System.out.println("Password doesn't Matched");
+			
+		s.close();
+		ss.close();
+	}
+	public static String decryption(String encrypted)
+	{
+		String decrypted="";
+		char ch;
+		for(int i=0;i<encrypted.length();i++)
+		{
+			ch = encrypted.charAt(i);
+			if(ch > 'a' && ch < 'z')
+			{
+				ch = (char)(ch - 3);
+				if(ch > 'z')
+				{
+					ch = (char)(ch + 'z' - 'a'+1);
+				}
+				decrypted= decrypted + ch;
+			}
+			else if(ch >= 'A' && ch <= 'Z')
+			{
+				ch = (char)(ch - 3);
+				if(ch > 'Z')
+				{
+					ch = (char)(ch + 'Z' - 'A' + 1);
+				}
+				decrypted = decrypted + ch;
+			}
+			else
+			{
+				decrypted = decrypted + ch;
+			}
+		}
+		return decrypted;
+	}
+	private static String doHashing(String text) throws Exception{
+		MessageDigest md=MessageDigest.getInstance("MD5");
+		byte[] msg=md.digest(text.getBytes());
+		BigInteger bigInt=new BigInteger(1,msg);
+		String hashValue=bigInt.toString(16);
+		while(hashValue.length()<32)
+			hashValue+=0+hashValue;
+		return hashValue;
+	}
+	public static String checkPassword(String decrypted)throws Exception
+	{
+		String pwd = null;
+		Class.forName("com.mysql.cj.jdbc.Driver");
+		Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ns","root","");
+		Statement st = con.createStatement();
+		ResultSet rs = st.executeQuery("select * from password where pws ='" + decrypted +"';");
+		while(rs.next()){
+			pwd = rs.getString("pws");
+		}
+		return pwd;
+	}
+	
+}
\ No newline at end of file
diff --git a/19_KhushaliPanchal/Practicals/RSA.java b/19_KhushaliPanchal/Practicals/RSA.java
new file mode 100644
index 0000000..4ffe851
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/RSA.java
@@ -0,0 +1,38 @@
+import java.security.*;
+import javax.crypto.*;
+import javax.crypto.spec.*;
+import java.util.*;
+class RSA{
+	public KeyPairGenerator keygenerator;
+	public KeyPair myKey;
+	Cipher c;
+	public RSA() throws Exception{ 
+		keygenerator = KeyPairGenerator.getInstance("RSA");
+		keygenerator.initialize(1024) ;
+		myKey = keygenerator.generateKeyPair();
+		c = Cipher.getInstance("RSA");
+	
+	}
+	public byte[] doEncryption(String s) throws Exception {
+		c.init(Cipher.ENCRYPT_MODE,myKey.getPublic());
+		byte[] text = s.getBytes();
+		byte[] textEncrypted = c.doFinal(text);
+		return(textEncrypted);
+	}
+	public String doDecryption(byte[] s)throws Exception{
+		c.init(Cipher.DECRYPT_MODE,myKey.getPrivate());
+		byte[] textDecrypted = c.doFinal(s);
+		return(new String(textDecrypted));
+	}
+	
+	public static void main(String[] argv) throws Exception{
+		Scanner sc = new Scanner(System.in);
+		System.out.println("Enter Plain Text:");
+		String text = sc.nextLine();
+		RSA d=new RSA();
+		byte[] str=d.doEncryption(text);
+		System.out.println("Encrypted String : "+str);
+		System.out.println("Decrypted String : "+d.doDecryption(str));
+		
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/SHA.java b/19_KhushaliPanchal/Practicals/SHA.java
new file mode 100644
index 0000000..95e5f9a
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/SHA.java
@@ -0,0 +1,21 @@
+import java.util.Scanner;
+import java.math.*;
+import java.security.*;
+class SHA{
+	private String doEncryption(String text) throws Exception{
+		MessageDigest md=MessageDigest.getInstance("SHA-1");
+		byte[] msg=md.digest(text.getBytes());
+		BigInteger bigInt=new BigInteger(1,msg);
+		String hashValue=bigInt.toString(16);
+		while(hashValue.length()<32)
+			hashValue+=0+hashValue;
+		return hashValue;
+	}
+	public static void main(String args[]) throws Exception{
+		SHA sha=new SHA();
+		Scanner sc=new Scanner(System.in);
+		System.out.print("\nEnter Message: ");
+		String text=sc.nextLine();
+		System.out.print("\nHash Text: " + sha.doEncryption(text));
+	}
+}
diff --git a/19_KhushaliPanchal/Practicals/SHA256.java b/19_KhushaliPanchal/Practicals/SHA256.java
new file mode 100644
index 0000000..730b7ca
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/SHA256.java
@@ -0,0 +1,37 @@
+import java.util.*;
+import java.math.BigInteger; 
+import java.nio.charset.StandardCharsets; 
+import java.security.MessageDigest; 
+import java.security.NoSuchAlgorithmException; 
+class SHA256{ 
+	public static byte[] getSHA(String input) throws NoSuchAlgorithmException 
+	{ 
+		MessageDigest md = MessageDigest.getInstance("SHA-256"); 
+		return md.digest(input.getBytes(StandardCharsets.UTF_8)); 
+	} 
+	
+	public static String toHexString(byte[] hash) 
+	{ 
+		BigInteger number = new BigInteger(1, hash); 
+		StringBuilder hexString = new StringBuilder(number.toString(16)); 
+		while (hexString.length() < 32) 
+		{ 
+			hexString.insert(0, '0'); 
+		} 
+
+		return hexString.toString(); 
+	} 
+
+	public static void main(String args[]) 
+	{ 
+		Scanner sc = new Scanner(System.in);
+		System.out.println("Enter Text");
+		try
+		{ 
+			String s1 = sc.nextLine();
+			System.out.println("HashCode Generated by SHA-256 for:"); 
+			System.out.println("\n" + s1 + " : " + toHexString(getSHA(s1))); 
+
+		}catch (Exception e) { e.printStackTrace();} 
+	} 
+} 
diff --git a/19_KhushaliPanchal/Practicals/Substitution_Cipher.java b/19_KhushaliPanchal/Practicals/Substitution_Cipher.java
new file mode 100644
index 0000000..f11bb0c
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/Substitution_Cipher.java
@@ -0,0 +1,67 @@
+import java.util.Scanner;
+class Substitution_Cipher{
+	Scanner sc;
+	String plain_text,cipher_text,decrypted_text;
+	int shift;
+	Substitution_Cipher(){
+		sc=new Scanner(System.in);
+		cipher_text="";
+		decrypted_text="";
+		shift=0;
+	}
+	void getData(){
+		System.out.print("Enter Plain Text : ");
+		plain_text=sc.nextLine();
+		plain_text=plain_text.trim();
+		System.out.print("\nEnterShift : ");
+		shift=sc.nextInt();
+	}
+	void encryptData(){
+		char ch;
+		for(int i=0;i<plain_text.length();i++){
+			ch=plain_text.charAt(i);
+			if(ch>='A' &&ch<='Z'){
+				ch=(char)(ch+shift);
+				if(ch>'Z'){
+					ch=(char)(ch-'Z'+'A'-1);
+				}
+				cipher_text=cipher_text+ch;
+			}
+			else if(ch>='a' &&ch<='z'){
+				ch=(char)(ch+shift);
+				if(ch>'z'){
+					ch=(char)(ch-'z'+'a'-1);
+				}
+				cipher_text=cipher_text+ch;
+			}
+		}
+		System.out.println("Cipher Text  :  "+cipher_text);
+	}
+	void decryptData(){
+		char ch;
+		for(int i=0;i<cipher_text.length();i++){
+			ch=cipher_text.charAt(i);
+			if(ch>='A' &&ch<='Z'){
+				ch=(char)(ch-shift);
+				if(ch<'A'){
+					ch=(char)(ch-'A'+'Z'+1);
+				}
+				decrypted_text=decrypted_text+ch;
+			}
+			else if(ch>='a' &&ch<='z'){
+				ch=(char)(ch+shift);
+				if(ch<'a'){
+					ch=(char)(ch-'a'+'z'+1);
+				}
+				decrypted_text=decrypted_text+ch;
+			}
+		}
+		System.out.println("Decrypted Text  :  "+decrypted_text);
+	}
+	public static void main(String args[]){
+		Substitution_Cipher cc=new Substitution_Cipher();
+		cc.getData();
+		cc.encryptData();
+		cc.decryptData();
+	}
+}	
diff --git a/19_KhushaliPanchal/Practicals/Transposition.java b/19_KhushaliPanchal/Practicals/Transposition.java
new file mode 100644
index 0000000..1cf4b82
--- /dev/null
+++ b/19_KhushaliPanchal/Practicals/Transposition.java
@@ -0,0 +1,83 @@
+import java.util.*;
+class Transposition{
+	public static void main(String args[])throws Exception{
+		Scanner sc=new Scanner(System.in);
+		System.out.print("\nEnterkey(of unique alphabets): ");
+		String k=sc.nextLine();
+		char[] key=k.toCharArray();
+		char[] temp_key=new char[key.length];
+		System.arraycopy(key,0,temp_key,0,key.length);
+		Arrays.sort(temp_key);
+		System.out.print("\nEnter string: ");
+		String t=sc.nextLine();
+		char[] str=t.toCharArray();
+		for(int i=0;i<str.length;i++){
+			if(str[i]==' ')
+				str[i]='$';
+		}
+		int index=0,row;
+		if(((str.length)%(key.length))==0){
+			row=((str.length)/(key.length));
+		}else{
+			row=((str.length)/(key.length))+1;
+		}
+		
+		char[] cipher=new char[(row*(key.length))];
+		int ci=0;
+		while(ci<(row*(key.length))){
+			for(int i=0;i<key.length;i++){
+				index=0;
+				for(int j=0;j<key.length;j++){	
+					if(temp_key[i]==key[j]){
+						index=j;
+						int l=0;
+						while(l<row){
+							if(index<str.length){
+							cipher[ci]=str[index];
+							ci++;
+							l++; 
+							index=index+(key.length);
+							}else{
+								cipher[ci]='!';
+								ci++;
+								l++;
+							}
+						}
+						break;
+					}
+				}
+			}
+		}
+	System.out.print("\nCipher text: ");
+		for(int i=0;i<cipher.length;i++){
+			System.out.print(cipher[i]);
+		}
+		char[] decipher=new char[cipher.length];
+		int di=0;
+		int l=0;
+		while(di<cipher.length){
+			for(int i=0;i<key.length;i++){
+				index=0;
+				for(int j=0;j<key.length;j++){	
+					if(key[i]==temp_key[j]){
+						index=((j)*row)+l;
+						decipher[di]=cipher[index];
+						if(decipher[di]=='$'){
+							decipher[di]=' ';
+						}
+						if(decipher[di]=='!'){
+							decipher[di]='\0';
+						}
+						di++;
+						break;
+					}
+				}
+			}
+			l++;
+		}
+		System.out.print("\ndecipher text: ");
+		for(int i=0;i<cipher.length;i++){
+			System.out.print(decipher[i]);
+		}
+	}
+}
diff --git a/19_KhushaliPanchal/Theory/NS assignment(1).pdf b/19_KhushaliPanchal/Theory/NS assignment(1).pdf
new file mode 100644
index 0000000..a0fa467
Binary files /dev/null and b/19_KhushaliPanchal/Theory/NS assignment(1).pdf differ