Android编程加密算法小结(AES、Base64、RAS加密算法)

package com.long;/** * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.OutputStream;/* * @author long * */public class Base64 { private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"   .toCharArray(); public static String encode(byte[] data) {  int start = 0;  int len = data.length;  StringBuffer buf = new StringBuffer(data.length * 3 / 2);  int end = len - 3;  int i = start;  int n = 0;  while (i <= end) {   int d = ((((int) data[i]) & 0x0ff) << 16)     | ((((int) data[i + 1]) & 0x0ff) << 8)     | (((int) data[i + 2]) & 0x0ff);   buf.append(legalChars[(d >> 18) & 63]);   buf.append(legalChars[(d >> 12) & 63]);   buf.append(legalChars[(d >> 6) & 63]);   buf.append(legalChars[d & 63]);   i += 3;   if (n++ >= 14) {    n = 0;    buf.append(" ");   }  }  if (i == start + len - 2) {   int d = ((((int) data[i]) & 0x0ff) << 16)     | ((((int) data[i + 1]) & 255) << 8);   buf.append(legalChars[(d >> 18) & 63]);   buf.append(legalChars[(d >> 12) & 63]);   buf.append(legalChars[(d >> 6) & 63]);   buf.append("=");  } else if (i == start + len - 1) {   int d = (((int) data[i]) & 0x0ff) << 16;   buf.append(legalChars[(d >> 18) & 63]);   buf.append(legalChars[(d >> 12) & 63]);   buf.append("==");  }  return buf.toString(); } private static int decode(char c) {  if (c >= 'A' && c <= 'Z')   return ((int) c) - 65;  else if (c >= 'a' && c <= 'z')   return ((int) c) - 97 + 26;  else if (c >= '0' && c <= '9')   return ((int) c) - 48 + 26 + 26;  else   switch (c) {   case '+':    return 62;   case '/':    return 63;   case '=':    return 0;   default:    throw new RuntimeException("unexpected code: " + c);   } } public static byte[] decode(String s) {  ByteArrayOutputStream bos = new ByteArrayOutputStream();  try {   decode(s, bos);  } catch (IOException e) {   throw new RuntimeException();  }  byte[] decodedBytes = bos.toByteArray();  try {   bos.close();   bos = null;  } catch (IOException ex) {   System.err.println("Error while decoding BASE64: " + ex.toString());  }  return decodedBytes; } private static void decode(String s, OutputStream os) throws IOException {  int i = 0;  int len = s.length();  while (true) {   while (i < len && s.charAt(i) <= ' ')    i++;   if (i == len)    break;   int tri = (decode(s.charAt(i)) << 18)     + (decode(s.charAt(i + 1)) << 12)     + (decode(s.charAt(i + 2)) << 6)     + (decode(s.charAt(i + 3)));   os.write((tri >> 16) & 255);   if (s.charAt(i + 2) == '=')    break;   os.write((tri >> 8) & 255);   if (s.charAt(i + 3) == '=')    break;   os.write(tri & 255);   i += 4;  } }}

package com.long;import java.security.SecureRandom;import javax.crypto.Cipher;import javax.crypto.KeyGenerator;import javax.crypto.SecretKey;import javax.crypto.spec.SecretKeySpec;/** * AES加密解密算法 *  * @author long *  */public class Encryption { private final static String HEX = "0123456789ABCDEF"; 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 static void appendHex(StringBuffer sb, byte b) {  sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f)); }}

import java.security.Key; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.PrivateKey; import java.security.PublicKey; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import javax.crypto.Cipher; import sun.misc.BASE64Decoder; import sun.misc.BASE64Encoder; public class RSAHelper {   public static PublicKey getPublicKey(String key) throws Exception {    byte[] keyBytes;    keyBytes = (new BASE64Decoder()).decodeBuffer(key);    X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);    KeyFactory keyFactory = KeyFactory.getInstance("RSA");    PublicKey publicKey = keyFactory.generatePublic(keySpec);    return publicKey;   }   public static PrivateKey getPrivateKey(String key) throws Exception {    byte[] keyBytes;    keyBytes = (new BASE64Decoder()).decodeBuffer(key);    PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);    KeyFactory keyFactory = KeyFactory.getInstance("RSA");    PrivateKey privateKey = keyFactory.generatePrivate(keySpec);    return privateKey;   }   public static String getKeyString(Key key) throws Exception {    byte[] keyBytes = key.getEncoded();    String s = (new BASE64Encoder()).encode(keyBytes);    return s;   }   public static void main(String[] args) throws Exception {    KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");    //密钥位数    keyPairGen.initialize(1024);    //密钥对    KeyPair keyPair = keyPairGen.generateKeyPair();    // 公钥    PublicKey publicKey = (RSAPublicKey) keyPair.getPublic();    // 私钥    PrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();    String publicKeyString = getKeyString(publicKey);    System.out.println("public:/n" + publicKeyString);    String privateKeyString = getKeyString(privateKey);    System.out.println("private:/n" + privateKeyString);    //加解密类    Cipher cipher = Cipher.getInstance("RSA");//Cipher.getInstance("RSA/ECB/PKCS1Padding");    //明文    byte[] plainText = "我们都很好！邮件：@sina.com".getBytes();    //加密    cipher.init(Cipher.ENCRYPT_MODE, publicKey);    byte[] enBytes = cipher.doFinal(plainText);    //通过密钥字符串得到密钥    publicKey = getPublicKey(publicKeyString);    privateKey = getPrivateKey(privateKeyString);    //解密    cipher.init(Cipher.DECRYPT_MODE, privateKey);    byte[]deBytes = cipher.doFinal(enBytes);    publicKeyString = getKeyString(publicKey);    System.out.println("public:/n" +publicKeyString);    privateKeyString = getKeyString(privateKey);    System.out.println("private:/n" + privateKeyString);    String s = new String(deBytes);    System.out.println(s);   } }