BC7v9uZE

1        /*
2 * To change this license header, choose License Headers in Project Properties.
3 * To change this template file, choose Tools | Templates
4 * and open the template in the editor.
5 */
6package symasymcrypto;
7
8/**
9 *
10 * @author student
11 */
12
13import java.security.Key;
14import java.security.KeyPair;
15import java.security.KeyPairGenerator;
16import java.security.Security;
17import java.security.SecureRandom;
18import javax.crypto.Cipher;
19import java.security.InvalidKeyException;
20import java.security.NoSuchAlgorithmException;
21import javax.crypto.BadPaddingException;
22import javax.crypto.IllegalBlockSizeException;
23import javax.crypto.NoSuchPaddingException;
24import javax.crypto.SecretKey;
25import javax.crypto.SecretKeyFactory;
26import javax.crypto.ShortBufferException;
27import javax.crypto.spec.IvParameterSpec;
28import javax.crypto.spec.PBEKeySpec;
29import javax.crypto.spec.SecretKeySpec;
30import javax.rmi.CORBA.Util;
31
32
33public class SymAsymCrypto {
34
35    /**
36     * @param args the command line arguments
37     */
38    public static void main(String[] args) throws Exception {
39        // TODO code application logic here
40        
41        byte[] keyBytes = new byte[16];
42        // declare secure PRNG
43        SecureRandom myPRNG = new SecureRandom();
44        // seed the key
45        myPRNG.nextBytes(keyBytes);
46        // build the key from random key bytes
47        SecretKeySpec myKey = new SecretKeySpec(keyBytes, "AES");
48        IvParameterSpec IV = new IvParameterSpec(keyBytes);
49        // instantiate AES object for ECB with no padding
50        Cipher myAES = Cipher.getInstance("AES/CBC/NoPadding");
51        // initialize AES objecy to encrypt mode
52        myAES.init(Cipher.ENCRYPT_MODE, myKey, IV);
53        // initialize plaintext
54        byte[] plaintext = new byte[32];
55        //initialize ciphertext
56        byte[] ciphertext = new byte[32];
57        // update cipher with the plaintext
58        int cLength = myAES.update(plaintext, 0, plaintext.length, ciphertext,0);
59        // process remaining blocks of plaintext
60        cLength += myAES.doFinal(ciphertext, cLength);
61        // print plaintext and ciphertext
62        System.out.println("plaintext: " + javax.xml.bind.DatatypeConverter.printHexBinary(plaintext));
63        System.out.println("ciphertext: " + javax.xml.bind.DatatypeConverter.printHexBinary(ciphertext));
64        // initialize AES for decryption
65        myAES.init(Cipher.DECRYPT_MODE, myKey, IV);
66        // initialize a new array of bytes to place the decryption
67        byte[] dec_plaintext = new byte[32];
68        cLength = myAES.update(ciphertext, 0, ciphertext.length, dec_plaintext,0);
69        // process remaining blocks of ciphertext
70        cLength += myAES.doFinal(dec_plaintext, cLength);
71        // print the new plaintext (hopefully identical to the initial one)
72        System.out.println("decrypted: " + javax.xml.bind.DatatypeConverter.printHexBinary(dec_plaintext));
73        
74        // get a Cipher instance for RSA with PKCS1 padding
75        Cipher myRSA = Cipher.getInstance("RSA/ECB/PKCS1Padding");
76        // get an instance for the Key Generator
77        KeyPairGenerator myRSAKeyGen = KeyPairGenerator.getInstance("RSA");
78        // generate an 1024 bit key
79        myRSAKeyGen.initialize(1024, myPRNG);
80        KeyPair myRSAKeyPair= myRSAKeyGen.generateKeyPair();
81        // store the public and private key individually
82        Key pbKey = myRSAKeyPair.getPublic();
83        Key pvKey = myRSAKeyPair.getPrivate();
84        // init cipher for encryption
85        myRSA.init(Cipher.ENCRYPT_MODE, pbKey, myPRNG);
86        // encrypt, as expected we encrypt a symmetric key with RSA rather than
87        //a file or some longer stream which should be encrypted with AES
88        ciphertext = myRSA.doFinal(keyBytes);
89        // init cipher for decryption
90        myRSA.init(Cipher.DECRYPT_MODE, pvKey);
91        // decrypt
92        plaintext = myRSA.doFinal(ciphertext);
93        System.out.println("plaintext: " + javax.xml.bind.DatatypeConverter.printHexBinary(plaintext));
94        System.out.println("ciphertext: " + javax.xml.bind.DatatypeConverter.printHexBinary(ciphertext));
95        System.out.println("keybytes: " + javax.xml.bind.DatatypeConverter.printHexBinary(keyBytes));
96        
97        
98        char[] password = "short_password".toCharArray();
99        byte[] salt = new byte[16];
100        int iteration_count = 10000;
101        int key_size = 128;
102        // set salt values to random
103        myPRNG.nextBytes(salt);
104
105        // initialize key factory for HMAC-SHA1 derivation
106        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
107        // set key specification
108        PBEKeySpec pbekSpec = new PBEKeySpec(password, salt, iteration_count,key_size);
109        // generate the key
110        SecretKey myAESPBKey = new SecretKeySpec(keyFactory.generateSecret(pbekSpec).getEncoded(), "AES");
111        // print the key
112        System.out.println("AES key: " + javax.xml.bind.DatatypeConverter.printHexBinary(myAESPBKey.getEncoded()));
113    }
114    
115}