几种加密方式

1 Base64加密方式(可逆)

public class Base64Utils { private static final String TAG ="Base64Utils"; private static char[] base64EncodeChars = new char[]{'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'}; private static byte[] base64DecodeChars = new byte[]{-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1}; /** * 加密 * * @param data * @return */ public static String encode(byte[] data) { StringBuffer sb = new StringBuffer(); int len = data.length; int i = 0; int b1, b2, b3; while (i < len) { b1 = data[i++] & 0xff; if (i == len) { sb.append(base64EncodeChars[b1 >>> 2]); sb.append(base64EncodeChars[(b1 & 0x3) << 4]); sb.append("=="); break; } b2 = data[i++] & 0xff; if (i == len) { sb.append(base64EncodeChars[b1 >>> 2]); sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]); sb.append(base64EncodeChars[(b2 & 0x0f) << 2]); sb.append("="); break; } b3 = data[i++] & 0xff; sb.append(base64EncodeChars[b1 >>> 2]); sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]); sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]); sb.append(base64EncodeChars[b3 & 0x3f]); } return sb.toString(); } /** * 解密 * * @param str * @return */ public static byte[] decode(String str) { try { return decodePrivate(str); } catch (UnsupportedEncodingException e) { e.printStackTrace();MyLog.e(TAG,e); } return new byte[]{}; } private static byte[] decodePrivate(String str) throws UnsupportedEncodingException { StringBuffer sb = new StringBuffer(); byte[] data = null; data = str.getBytes("US-ASCII"); int len = data.length; int i = 0; int b1, b2, b3, b4; while (i < len) { do { b1 = base64DecodeChars[data[i++]]; } while (i < len && b1 == -1); if (b1 == -1) break; do { b2 = base64DecodeChars[data[i++]]; } while (i < len && b2 == -1); if (b2 == -1) break; sb.append((char) ((b1 << 2) | ((b2 & 0x30) >>> 4))); do { b3 = data[i++]; if (b3 == 61) return sb.toString().getBytes("iso8859-1"); b3 = base64DecodeChars[b3]; } while (i < len && b3 == -1); if (b3 == -1) break; sb.append((char) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2))); do { b4 = data[i++]; if (b4 == 61) return sb.toString().getBytes("iso8859-1"); b4 = base64DecodeChars[b4]; } while (i < len && b4 == -1); if (b4 == -1) break; sb.append((char) (((b3 & 0x03) << 6) | b4)); } return sb.toString().getBytes("iso8859-1"); } }

2 MD5加密（不可逆）

public class MD5 { /** * describe MD5加密一段字符 * * @param value 要加密的字符 * @return String 加密后的字符 */ public static String digest(String value) { StringBuilder sb = null; try { MessageDigest digest = MessageDigest.getInstance("MD5"); byte[] result = digest.digest(value.getBytes()); sb = new StringBuilder(); for (byte b : result) { String hexString = Integer.toHexString(b & 0xFF); if (hexString.length() == 1) { sb.append("0" + hexString);// 0~F } else { sb.append(hexString); } } } catch (NoSuchAlgorithmException e) { throw new RuntimeException(e); } return sb.toString().toUpperCase(); } }

3 RSA加密（需要公私钥进行加解密）

public final class RSAUtils { private static String RSA = "RSA"; /** * 随机生成RSA密钥对(默认密钥长度为1024) * * @return */ public static KeyPair generateRSAKeyPair() { return generateRSAKeyPair(1024); } /** * 随机生成RSA密钥对 * * @param keyLength 密钥长度，范围：512～2048<br> * 一般1024 * @return */ public static KeyPair generateRSAKeyPair(int keyLength) { try { KeyPairGenerator kpg = KeyPairGenerator.getInstance(RSA); kpg.initialize(keyLength); return kpg.genKeyPair(); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); return null; } } /** * 用公钥加密 <br> * 每次加密的字节数，不能超过密钥的长度值减去11 * * @param data 需加密数据的byte数据 * @param publicKey 公钥 * @return 加密后的byte型数据 */ public static byte[] encryptData(byte[] data, PublicKey publicKey) { try { Cipher cipher = Cipher.getInstance(RSA); // 编码前设定编码方式及密钥 cipher.init(Cipher.ENCRYPT_MODE, publicKey); // 传入编码数据并返回编码结果 return cipher.doFinal(data); } catch (Exception e) { e.printStackTrace(); return null; } } /** * 用私钥解密 * * @param encryptedData 经过encryptedData()加密返回的byte数据 * @param privateKey 私钥 * @return */ public static byte[] decryptData(byte[] encryptedData, PrivateKey privateKey) { try { Cipher cipher = Cipher.getInstance(RSA); cipher.init(Cipher.DECRYPT_MODE, privateKey); byte[] output = cipher.doFinal(encryptedData); return output; } catch (Exception e) { return null; } } /** * 通过公钥byte[](publicKey.getEncoded())将公钥还原，适用于RSA算法 * * @param keyBytes * @return * @throws NoSuchAlgorithmException * @throws InvalidKeySpecException */ public static PublicKey getPublicKey(byte[] keyBytes) throws NoSuchAlgorithmException, InvalidKeySpecException { X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(RSA); PublicKey publicKey = keyFactory.generatePublic(keySpec); return publicKey; } /** * 通过私钥byte[]将公钥还原，适用于RSA算法 * * @param keyBytes * @return * @throws NoSuchAlgorithmException * @throws InvalidKeySpecException */ public static PrivateKey getPrivateKey(byte[] keyBytes) throws NoSuchAlgorithmException, InvalidKeySpecException { PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(RSA); PrivateKey privateKey = keyFactory.generatePrivate(keySpec); return privateKey; } /** * 使用N、e值还原公钥 * * @param modulus * @param publicExponent * @return * @throws NoSuchAlgorithmException * @throws InvalidKeySpecException */ public static PublicKey getPublicKey(String modulus, String publicExponent) throws NoSuchAlgorithmException, InvalidKeySpecException { BigInteger bigIntModulus = new BigInteger(modulus); BigInteger bigIntPrivateExponent = new BigInteger(publicExponent); RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent); KeyFactory keyFactory = KeyFactory.getInstance(RSA); PublicKey publicKey = keyFactory.generatePublic(keySpec); return publicKey; } /** * 使用N、d值还原私钥 * * @param modulus * @param privateExponent * @return * @throws NoSuchAlgorithmException * @throws InvalidKeySpecException */ public static PrivateKey getPrivateKey(String modulus, String privateExponent) throws NoSuchAlgorithmException, InvalidKeySpecException { BigInteger bigIntModulus = new BigInteger(modulus); BigInteger bigIntPrivateExponent = new BigInteger(privateExponent); RSAPublicKeySpec keySpec = new RSAPublicKeySpec(bigIntModulus, bigIntPrivateExponent); KeyFactory keyFactory = KeyFactory.getInstance(RSA); PrivateKey privateKey = keyFactory.generatePrivate(keySpec); return privateKey; } /** * 从字符串中加载公钥 * * @param publicKeyStr 公钥数据字符串 * @throws Exception 加载公钥时产生的异常 */ public static PublicKey loadPublicKey(String publicKeyStr) throws Exception { try { byte[] buffer = Base64Utils.decode(publicKeyStr); KeyFactory keyFactory = KeyFactory.getInstance(RSA); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer); return (RSAPublicKey) keyFactory.generatePublic(keySpec); } catch (NoSuchAlgorithmException e) { throw new Exception("无此算法"); } catch (InvalidKeySpecException e) { throw new Exception("公钥非法"); } catch (NullPointerException e) { throw new Exception("公钥数据为空"); } } /** * 从字符串中加载私钥<br> * 加载时使用的是PKCS8EncodedKeySpec（PKCS#8编码的Key指令）。 * * @param privateKeyStr * @return * @throws Exception */ public static PrivateKey loadPrivateKey(String privateKeyStr) throws Exception { try { byte[] buffer = Base64Utils.decode(privateKeyStr); // X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer); PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer); KeyFactory keyFactory = KeyFactory.getInstance(RSA); return (RSAPrivateKey) keyFactory.generatePrivate(keySpec); } catch (NoSuchAlgorithmException e) { throw new Exception("无此算法"); } catch (InvalidKeySpecException e) { throw new Exception("私钥非法"); } catch (NullPointerException e) { throw new Exception("私钥数据为空"); } } /** * 从文件中输入流中加载公钥 * * @param in 公钥输入流 * @throws Exception 加载公钥时产生的异常 */ public static PublicKey loadPublicKey(InputStream in) throws Exception { try { return loadPublicKey(readKey(in)); } catch (IOException e) { throw new Exception("公钥数据流读取错误"); } catch (NullPointerException e) { throw new Exception("公钥输入流为空"); } } /** * 从文件中加载私钥 * * @param in 私钥文件名 * @return 是否成功 * @throws Exception */ public static PrivateKey loadPrivateKey(InputStream in) throws Exception { try { return loadPrivateKey(readKey(in)); } catch (IOException e) { throw new Exception("私钥数据读取错误"); } catch (NullPointerException e) { throw new Exception("私钥输入流为空"); } } /** * 读取密钥信息 * * @param in * @return * @throws IOException */ private static String readKey(InputStream in) throws IOException { BufferedReader br = new BufferedReader(new InputStreamReader(in)); String readLine = null; StringBuilder sb = new StringBuilder(); while ((readLine = br.readLine()) != null) { if (readLine.charAt(0) == '-') { continue; } else { sb.append(readLine); sb.append('\r'); } } return sb.toString(); } /** * 打印公钥信息 * * @param publicKey */ public static void printPublicKeyInfo(PublicKey publicKey) { RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey; System.out.println("----------RSAPublicKey----------"); System.out.println("Modulus.length=" + rsaPublicKey.getModulus().bitLength()); System.out.println("Modulus=" + rsaPublicKey.getModulus().toString()); System.out.println("PublicExponent.length=" + rsaPublicKey.getPublicExponent().bitLength()); System.out.println("PublicExponent=" + rsaPublicKey.getPublicExponent().toString()); } public static void printPrivateKeyInfo(PrivateKey privateKey) { RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) privateKey; System.out.println("----------RSAPrivateKey ----------"); System.out.println("Modulus.length=" + rsaPrivateKey.getModulus().bitLength()); System.out.println("Modulus=" + rsaPrivateKey.getModulus().toString()); System.out.println("PrivateExponent.length=" + rsaPrivateKey.getPrivateExponent().bitLength()); System.out.println("PrivatecExponent=" + rsaPrivateKey.getPrivateExponent().toString()); } }

4 HmacSHA1加密

public class HmacSHA1Utils { private static final String MAC_NAME = "HmacSHA1"; private static final String ENCODING = "UTF-8"; /** * 使用 HMAC-SHA1 签名方法对对encryptText进行签名 * * @param encryptKey 密钥 * @param encryptText 被签名的字符串 * @return 签名后的字符串 * @throws Exception */ public static byte[] HmacSHA1Encrypt(String encryptKey, String encryptText) { try { byte[] data = encryptKey.getBytes(ENCODING); //根据给定的字节数组构造一个密钥,第二参数指定一个密钥算法的名称 SecretKey secretKey = new SecretKeySpec(data, MAC_NAME); //生成一个指定 Mac 算法 的 Mac 对象 Mac mac = Mac.getInstance(MAC_NAME); //用给定密钥初始化 Mac 对象 mac.init(secretKey); byte[] text = encryptText.getBytes(ENCODING); //完成 Mac 操作 byte[] rawHmac = mac.doFinal(text); StringBuilder sb = new StringBuilder(); for (byte b : rawHmac) { sb.append(byteToHexString(b)); } return sb.toString().getBytes(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (InvalidKeyException e) { e.printStackTrace(); } byte[] wrong = null; return wrong; } private static String byteToHexString(byte ib) { char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; char[] ob = new char[2]; ob[0] = Digit[(ib >>> 4) & 0X0f]; ob[1] = Digit[ib & 0X0F]; String s = new String(ob); return s; } }