简单加密

此篇文章是引用的，因为前几天别人问我关于md5加密的我不是很懂，今天幸好看见这篇文章希望对他有用

package net.sf.andhsli.hotspotlogin;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**
?* Usage:
?* <pre>
?* String crypto = SimpleCrypto.encrypt(masterpassword, cleartext)
?* ...
?* String cleartext = SimpleCrypto.decrypt(masterpassword, crypto)
?* </pre>
?* @author ferenc.hechler
?*/
public class SimpleCrypto {

?public static String encrypt(String seed, String cleartext) throws Exception {
??byte[] rawKey = getRawKey(seed.getBytes());
??byte[] result = encrypt(rawKey, cleartext.getBytes());
??return toHex(result);
?}
?
?public static String decrypt(String seed, String encrypted) throws Exception {
??byte[] rawKey = getRawKey(seed.getBytes());
??byte[] enc = toByte(encrypted);
??byte[] result = decrypt(rawKey, enc);
??return new String(result);
?}

?private static byte[] getRawKey(byte[] seed) throws Exception {
??KeyGenerator kgen = KeyGenerator.getInstance("AES");
??SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
??sr.setSeed(seed);
???? kgen.init(128, sr); // 192 and 256 bits may not be available
???? SecretKey skey = kgen.generateKey();
???? byte[] raw = skey.getEncoded();
???? return raw;
?}

?
?private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
???? SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
??Cipher cipher = Cipher.getInstance("AES");
???? cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
???? byte[] encrypted = cipher.doFinal(clear);
??return encrypted;
?}

?private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
???? SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
??Cipher cipher = Cipher.getInstance("AES");
???? cipher.init(Cipher.DECRYPT_MODE, skeySpec);
???? byte[] decrypted = cipher.doFinal(encrypted);
??return decrypted;
?}

?public static String toHex(String txt) {
??return toHex(txt.getBytes());
?}
?public static String fromHex(String hex) {
??return new String(toByte(hex));
?}
?
?public static byte[] toByte(String hexString) {
??int len = hexString.length()/2;
??byte[] result = new byte[len];
??for (int i = 0; i < len; i++)
???result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
??return result;
?}

?public static String toHex(byte[] buf) {
??if (buf == null)
???return "";
??StringBuffer result = new StringBuffer(2*buf.length);
??for (int i = 0; i < buf.length; i++) {
???appendHex(result, buf[i]);
??}
??return result.toString();
?}
?private final static String HEX = "0123456789ABCDEF";
?private static void appendHex(StringBuffer sb, byte b) {
??sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
?}
?
}

?

http://www.androidsnippets.org/snippets/39/

这个网站也是不错的