简单加密-优快云博客

本文介绍了一种使用AES加密算法进行数据加密的方法，并提供了详细的Java实现代码。该方法利用了SecureRandom和KeyGenerator来生成密钥，通过Cipher进行加密和解密操作。此外，还介绍了如何将加密后的字节数组转换为十六进制字符串。

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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));
}

}