From dc8dff83c8cf3029e3fccca2033840649ce7230e Mon Sep 17 00:00:00 2001
From: ritika-98 <ritikap1998@gmail.com>
Date: Wed, 20 May 2020 12:40:42 +0530
Subject: [PATCH] The DES with different function for encrypt and decrypt

---
 DESf.class | Bin 0 -> 2656 bytes
 DESf.java  | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+)
 create mode 100644 DESf.class
 create mode 100644 DESf.java

diff --git a/DESf.class b/DESf.class
new file mode 100644
index 0000000000000000000000000000000000000000..7c6e85483287474480f9f6e2d379bf14cb095668
GIT binary patch
literal 2656
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literal 0
HcmV?d00001

diff --git a/DESf.java b/DESf.java
new file mode 100644
index 0000000..dfbf5f5
--- /dev/null
+++ b/DESf.java
@@ -0,0 +1,103 @@
+import javax.crypto.*;
+import javax.crypto.spec.DESKeySpec;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+import java.io.*;
+import java.security.*;
+import java.security.spec.AlgorithmParameterSpec;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.KeySpec;
+
+public class DESf {
+    private static Cipher encryptCipher;
+    private static Cipher decryptCipher;
+    //private static byte[] iv =
+            //{ 0x0a, 0x01, 0x02, 0x03, 0x04, 0x0b, 0x0c, 0x0d };
+
+    public static void main(String[] args) {
+        String clearTextFile = args[0];
+        String cipherTextFile = args[1];
+        String clearTextNewFile = args[2];
+
+        try {
+            // create SecretKey using KeyGenerator
+
+            KeyGenerator keyGenerator = KeyGenerator.getInstance("DES");
+            SecureRandom secureRandom = new SecureRandom();
+            int keyBitSize = 56;
+            keyGenerator.init(keyBitSize,secureRandom);
+            SecretKey key = keyGenerator.generateKey();
+//            AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
+
+//            System.out.println(key);
+//            Cipher cipher = Cipher.getInstance("DES/ECB/PKCS7Padding", "BC")
+
+            // get Cipher instance and initiate in encrypt mode
+            encryptCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
+            encryptCipher.init(Cipher.ENCRYPT_MODE, key);
+            // method to encrypt clear text file to encrypted file
+            encrypt(new FileInputStream(clearTextFile), new FileOutputStream(cipherTextFile));
+//            System.out.println(encryptCipher.getBlockSize());
+            // get Cipher instance and initiate in decrypt mode
+            decryptCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
+            decryptCipher.init(Cipher.DECRYPT_MODE, key);
+            //method to decrypt encrypted file to clear text file
+           decrypt(new FileInputStream(cipherTextFile), new FileOutputStream(clearTextNewFile));
+
+           
+            // method to decrypt encrypted file to clear text file
+            //decrypt(new FileInputStream(cipherTextFile), new FileOutputStream(clearTextNewFile));
+        } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IOException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    private static void encrypt(InputStream is, OutputStream os) throws IOException {
+        long startTime = System.nanoTime();
+        // create CipherOutputStream to encrypt the data using encryptCipher
+        CipherOutputStream cos = new CipherOutputStream(os, encryptCipher);
+        ///1000000;
+        writeDataEncrypt(is, cos);
+        long endTime = System.nanoTime();
+        long totalTime = (endTime - startTime)/1000000;
+        System.out.println(totalTime);
+    }
+
+    private static void decrypt(InputStream is, OutputStream os) throws IOException {
+
+        long startTime = System.nanoTime();
+        // create CipherOutputStream to decrypt the data using decryptCipher
+        CipherInputStream cis = new CipherInputStream(is, decryptCipher);
+       
+        writeDataDecrypt(cis, os);
+        long endTime = System.nanoTime();
+        long totalTime = (endTime - startTime)/1000000;
+        System.out.println(totalTime);
+    }
+
+    // utility method to read data from input stream and write to output stream
+    private static void writeDataEncrypt(InputStream is, CipherOutputStream os) throws IOException {
+        byte[] buf = new byte[8];
+        int numRead = 0;
+        // read and write operation
+        while ((numRead = is.read(buf)) >= 0) {
+            os.write(buf, 0, numRead);
+        }
+        os.flush();
+        os.close();
+        is.close();
+    }
+    private static void writeDataDecrypt(CipherInputStream is, OutputStream os) throws IOException {
+        byte[] buf = new byte[8];
+        int numRead = 0;
+        // read and write operation
+        while ((numRead = is.read(buf)) >= 0) {
+            os.write(buf, 0, numRead);
+        }
+        //os.flush();
+        os.close();
+        is.close();
+    }
+
+}
\ No newline at end of file