加密和解密的字符串:

package eoe.demo;

import java.security.SecureRandom;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

/**

* Usage:

*

* String crypto = SimpleCrypto.encrypt(masterpassword, cleartext)

* ...

* String cleartext = SimpleCrypto.decrypt(masterpassword, crypto)

*

* @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));

}

}