Android加密算法:AES、Base64加密算法

android常用加密算法之Base64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;elseswitch (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;}}}

android常用加密算法之AES加密算法：

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 availableSecretKey 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));}}

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