AES对称加密例子

原文地址http://java.sun.com/developer/technicalArticles/Security/AES/AES_v1.html
2000年9月开始，nist开始支持fips，来取代已经过时的des（Data Enryption Strandard）.

1 什么是AES
     AES是一种对称的私钥加密技术。它支持128，192，256位加密。


2 AES和Java
     从j2se1.4.2开始，集成了JCE包。
     现在的java支持128位key的加密。（下面的程序也是以128位为例讲解的）


3 如何使用JCE
例

import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.io.*;

/**
* This program generates a AES key, retrieves its raw bytes, and
* then reinstantiates a AES key from the key bytes.
* The reinstantiated key is used to initialize a AES cipher for
* encryption and decryption.
*/

public class AES {

  /**
  * Turns array of bytes into string
  *
  * @param buf  Array of bytes to convert to hex string
  * @return Generated hex string
  */
  public static String asHex (byte buf[]) {
   StringBuffer strbuf = new StringBuffer(buf.length * 2);
   int i;

   for (i = 0; i < buf.length; i++) {
    if (((int) buf[i] & 0xff) < 0x10)
  strbuf.append("0");

    strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
   }

   return strbuf.toString();
  }

  public static void main(String[] args) throws Exception {

    String message="This is just an example";

    // Get the KeyGenerator

    KeyGenerator kgen = KeyGenerator.getInstance("AES");
    kgen.init(128); // 192 and 256 bits may not be available


    // Generate the secret key specs.
    SecretKey skey = kgen.generateKey();
    byte[] raw = skey.getEncoded();

    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");


    // Instantiate the cipher

    Cipher cipher = Cipher.getInstance("AES");

    cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

    byte[] encrypted =
      cipher.doFinal((args.length == 0 ?
       "This is just an example" : args[0]).getBytes());
    System.out.println("encrypted string: " + asHex(encrypted));

    cipher.init(Cipher.DECRYPT_MODE, skeySpec);
    byte[] original =
      cipher.doFinal(encrypted);
    String originalString = new String(original);
    System.out.println("Original string: " +
      originalString + " " + asHex(original));
  }
}

import java.security.*; import javax.crypto.*; import javax.crypto.spec.*; import java.io.*; /** * This program generates a AES key, retrieves its raw bytes, and * then reinstantiates a AES key from the key bytes. * The reinstantiated key is used to initialize a AES cipher for * encryption and decryption. */ public class AES { /** * Turns array of bytes into string * * @param buf Array of bytes to convert to hex string * @return Generated hex string */ public static String asHex (byte buf[]) { StringBuffer strbuf = new StringBuffer(buf.length * 2); int i; for (i = 0; i < buf.length; i++) { if (((int) buf[i] & 0xff) < 0x10) strbuf.append("0"); strbuf.append(Long.toString((int) buf[i] & 0xff, 16)); } return strbuf.toString(); } public static void main(String[] args) throws Exception { String message="This is just an example"; // Get the KeyGenerator KeyGenerator kgen = KeyGenerator.getInstance("AES"); kgen.init(128); // 192 and 256 bits may not be available // Generate the secret key specs. SecretKey skey = kgen.generateKey(); byte[] raw = skey.getEncoded(); SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); // Instantiate the cipher Cipher cipher = Cipher.getInstance("AES"); cipher.init(Cipher.ENCRYPT_MODE, skeySpec); byte[] encrypted = cipher.doFinal((args.length == 0 ? "This is just an example" : args[0]).getBytes()); System.out.println("encrypted string: " + asHex(encrypted)); cipher.init(Cipher.DECRYPT_MODE, skeySpec); byte[] original = cipher.doFinal(encrypted); String originalString = new String(original); System.out.println("Original string: " + originalString + " " + asHex(original)); } }
4 更强壮的加密
   kgen.init(256); // 128 and 192 bits also available
   按照原文提示的地址可以更新下一个包，然后稍微修改下加密位数就可以了。不过jdk1.4默认只支持128位的加密，实际上，作者也建议同时利用SSL,比单独一味强调加密位数效果要好。
5 同时使用SSL和AES

server端

import java.io.*;
import java.security.*;
import javax.net.ssl.*;


import java.util.regex.*;


public class HelloServerSSL {
  public static void main(String[] args) {
    SSLServerSocket s;


    // Pick all AES algorithms of 256 bits key size
    String patternString = "AES.*256";
    Pattern pattern = Pattern.compile(patternString);
    Matcher matcher;
    boolean matchFound;

    try {
      SSLServerSocketFactory sslSrvFact =
        (SSLServerSocketFactory)
          SSLServerSocketFactory.getDefault();
      s =(SSLServerSocket)sslSrvFact.createServerSocket(8181);

      SSLSocket in = (SSLSocket)s.accept();


      String str[]=in.getSupportedCipherSuites();

      int len = str.length;
      String set[] = new String[len];

      int j=0, k = len-1;
      for (int i=0; i < len; i++) {

        // Determine if pattern exists in input
        matcher = pattern.matcher(str[i]);
        matchFound = matcher.find();

        if (matchFound)
          set[j++] = str[i];
        else
          set[k--] = str[i];
      }

      in.setEnabledCipherSuites(set);

      str=in.getEnabledCipherSuites();

      System.out.println("Available Suites after Set:");
      for (int i=0; i < str.length; i++)
        System.out.println(str[i]);
      System.out.println("Using cipher suite: " +
         (in.getSession()).getCipherSuite());

      PrintWriter out = new PrintWriter (in.getOutputStream(),
                        true);
      out.println("Hello on a SSL socket");
      in.close();
    } catch (Exception e) {
      System.out.println("Exception" + e);
    }
  }
}

import java.io.*; import java.security.*; import javax.net.ssl.*; import java.util.regex.*; public class HelloServerSSL { public static void main(String[] args) { SSLServerSocket s; // Pick all AES algorithms of 256 bits key size String patternString = "AES.*256"; Pattern pattern = Pattern.compile(patternString); Matcher matcher; boolean matchFound; try { SSLServerSocketFactory sslSrvFact = (SSLServerSocketFactory) SSLServerSocketFactory.getDefault(); s =(SSLServerSocket)sslSrvFact.createServerSocket(8181); SSLSocket in = (SSLSocket)s.accept(); String str[]=in.getSupportedCipherSuites(); int len = str.length; String set[] = new String[len]; int j=0, k = len-1; for (int i=0; i < len; i++) { // Determine if pattern exists in input matcher = pattern.matcher(str[i]); matchFound = matcher.find(); if (matchFound) set[j++] = str[i]; else set[k--] = str[i]; } in.setEnabledCipherSuites(set); str=in.getEnabledCipherSuites(); System.out.println("Available Suites after Set:"); for (int i=0; i < str.length; i++) System.out.println(str[i]); System.out.println("Using cipher suite: " + (in.getSession()).getCipherSuite()); PrintWriter out = new PrintWriter (in.getOutputStream(), true); out.println("Hello on a SSL socket"); in.close(); } catch (Exception e) { System.out.println("Exception" + e); } } }

client端

import java.io.*;
import java.security.*;
import javax.net.ssl.*;


import java.util.regex.*;


public class HelloClientSSL {
  public static void main(String[] args) {


    // Pick all AES algorithms of 256 bits key size
    String patternString = "AES.*256";
    Pattern pattern = Pattern.compile(patternString);
    Matcher matcher;
    boolean matchFound;

    try {

      SSLSocketFactory sslFact =
        (SSLSocketFactory)SSLSocketFactory.getDefault();
      SSLSocket s =
        (SSLSocket)sslFact.createSocket(args.length == 0 ?
          "127.0.0.1" : args[0], 8181);

      String str[]=s.getSupportedCipherSuites();

      int len = str.length;
      String set[] = new String[len];

      int j=0, k = len-1;
      for (int i=0; i < len; i++) {
        System.out.println(str[i]);

        // Determine if pattern exists in input
        matcher = pattern.matcher(str[i]);
        matchFound = matcher.find();

        if (matchFound)
          set[j++] = str[i];
        else
          set[k--] = str[i];
      }

      s.setEnabledCipherSuites(set);

      str=s.getEnabledCipherSuites();

      System.out.println("Available Suites after Set:");
      for (int i=0; i < str.length; i++)
        System.out.println(str[i]);

      OutputStream out = s.getOutputStream();
      BufferedReader in = new BufferedReader (
        new InputStreamReader(s.getInputStream()));

      String mesg = in.readLine();
      System.out.println("Socket message: " + mesg);
      in.close();
    } catch (Exception e) {
      System.out.println("Exception" + e);
    }
  }
}

import java.io.*; import java.security.*; import javax.net.ssl.*; import java.util.regex.*; public class HelloClientSSL { public static void main(String[] args) { // Pick all AES algorithms of 256 bits key size String patternString = "AES.*256"; Pattern pattern = Pattern.compile(patternString); Matcher matcher; boolean matchFound; try { SSLSocketFactory sslFact = (SSLSocketFactory)SSLSocketFactory.getDefault(); SSLSocket s = (SSLSocket)sslFact.createSocket(args.length == 0 ? "127.0.0.1" : args[0], 8181); String str[]=s.getSupportedCipherSuites(); int len = str.length; String set[] = new String[len]; int j=0, k = len-1; for (int i=0; i < len; i++) { System.out.println(str[i]); // Determine if pattern exists in input matcher = pattern.matcher(str[i]); matchFound = matcher.find(); if (matchFound) set[j++] = str[i]; else set[k--] = str[i]; } s.setEnabledCipherSuites(set); str=s.getEnabledCipherSuites(); System.out.println("Available Suites after Set:"); for (int i=0; i < str.length; i++) System.out.println(str[i]); OutputStream out = s.getOutputStream(); BufferedReader in = new BufferedReader ( new InputStreamReader(s.getInputStream())); String mesg = in.readLine(); System.out.println("Socket message: " + mesg); in.close(); } catch (Exception e) { System.out.println("Exception" + e); } } }



运行结果
  
Available Suites after Set:TLS_RSA_WITH_AES_256_CBC_SHATLS_DHE_RSA_WITH_AES_256_CBC_SHATLS_DHE_DSS_WITH_AES_256_CBC_SHATLS_DH_anon_WITH_AES_256_CBC_SHASSL_DH_anon_EXPORT_WITH_DES40_CBC_SHASSL_DH_anon_EXPORT_WITH_RC4_40_MD5SSL_DH_anon_WITH_DES_CBC_SHASSL_DH_anon_WITH_3DES_EDE_CBC_SHATLS_DH_anon_WITH_AES_128_CBC_SHASSL_DH_anon_WITH_RC4_128_MD5SSL_RSA_WITH_NULL_SHASSL_RSA_WITH_NULL_MD5SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHASSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHASSL_RSA_EXPORT_WITH_DES40_CBC_SHASSL_RSA_EXPORT_WITH_RC4_40_MD5SSL_DHE_DSS_WITH_DES_CBC_SHASSL_DHE_RSA_WITH_DES_CBC_SHASSL_RSA_WITH_DES_CBC_SHASSL_DHE_DSS_WITH_3DES_EDE_CBC_SHASSL_DHE_RSA_WITH_3DES_EDE_CBC_SHASSL_RSA_WITH_3DES_EDE_CBC_SHATLS_DHE_DSS_WITH_AES_128_CBC_SHATLS_DHE_RSA_WITH_AES_128_CBC_SHATLS_RSA_WITH_AES_128_CBC_SHASSL_RSA_WITH_RC4_128_SHASSL_RSA_WITH_RC4_128_MD5Using cipher suite: TLS_RSA_WITH_AES_256_CBC_SHA







别人的例子

/**
*PrivateExmaple.java
*Copyright 2005-2-16
*/
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import java.security.Key;

/**
*˽?¼ÓÃÜ&&±&Ö¤Ï&Ï&&uÃÜÐÔ
*/
public class PrivateExample{
    public static void main(String[] args) throws Exception{

    byte[] plainText="12345678".getBytes();

    //Í‥¹&KeyGeneratorÐγÉÒ&&&key
    System.out.println("\nStart generate AES key");
    KeyGenerator keyGen=KeyGenerator.getInstance("AES");
    keyGen.init(128);
    Key key=keyGen.generateKey();
    System.out.println("Finish generating AES key");

    //&&&ÃÒ&&&˽?¼ÓÃÜÀaCipher&&ECBÊǼÓÃÜ·½Ê½&&PKCS5PaddingÊÇÌ&³&·½·‥
    Cipher cipher=Cipher.getInstance("AES/ECB/PKCS5Padding");
    System.out.println("\n"+cipher.getProvider().getInfo());

    //ʹÓÃ˽?¼ÓÃÜ
    System.out.println("\nStart encryption:");
    cipher.init(Cipher.ENCRYPT_MODE,key);
    byte[] cipherText=cipher.doFinal(plainText);
    System.out.println("Finish encryption:");
    System.out.println(new String(cipherText,"UTF8"));

    System.out.println("\nStart decryption:");
    cipher.init(Cipher.DECRYPT_MODE,key);
    byte[] newPlainText=cipher.doFinal(cipherText);
    System.out.println("Finish decryption:");

    System.out.println(new String(newPlainText,"UTF8"));
    }
}

/** *PrivateExmaple.java *Copyright 2005-2-16 */ import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import java.security.Key; /** *˽?¼ÓÃÜ&&±&Ö¤Ï&Ï&&uÃÜÐÔ */ public class PrivateExample{ public static void main(String[] args) throws Exception{ byte[] plainText="12345678".getBytes(); //Í‥¹&KeyGeneratorÐγÉÒ&&&key System.out.println("\nStart generate AES key"); KeyGenerator keyGen=KeyGenerator.getInstance("AES"); keyGen.init(128); Key key=keyGen.generateKey(); System.out.println("Finish generating AES key"); //&&&ÃÒ&&&˽?¼ÓÃÜÀaCipher&&ECBÊǼÓÃÜ·½Ê½&&PKCS5PaddingÊÇÌ&³&·½·‥ Cipher cipher=Cipher.getInstance("AES/ECB/PKCS5Padding"); System.out.println("\n"+cipher.getProvider().getInfo()); //ʹÓÃ˽?¼ÓÃÜ System.out.println("\nStart encryption:"); cipher.init(Cipher.ENCRYPT_MODE,key); byte[] cipherText=cipher.doFinal(plainText); System.out.println("Finish encryption:"); System.out.println(new String(cipherText,"UTF8")); System.out.println("\nStart decryption:"); cipher.init(Cipher.DECRYPT_MODE,key); byte[] newPlainText=cipher.doFinal(cipherText); System.out.println("Finish decryption:"); System.out.println(new String(newPlainText,"UTF8")); } }

自己稍加修改的例子

Java代码

byte[] plainText="12345678".getBytes();

        //Í‥¹&KeyGeneratorÐγÉÒ&&&key
        System.out.println("\nStart generate AES key");
        KeyGenerator keyGen=KeyGenerator.getInstance("AES");

        String pwd = "passord";
        keyGen.init(128, new SecureRandom(pwd.getBytes()));
        //keyGen.init(128);

        //Key key=keyGen.generateKey();
        SecretKey skey = keyGen.generateKey();
        byte[] raw = skey.getEncoded();

        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

        System.out.println("Finish generating AES key");

        //&&&ÃÒ&&&˽?¼ÓÃÜÀaCipher&&ECBÊǼÓÃÜ