Khushali Panchal

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)));
+	}
+}

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);
+	}
+}

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;
+	}
+
+}

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();
+	}
+}

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();
+	}
+
+}

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();
+
+	}
+}

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));
+	}
+}

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;
+		}
+	}
+}

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!");
+		}
+	}
+}