Java常用加密算法实例总结

public static byte[] encode2Base64(byte[] bytes) {    byte[] bts = Base64.encodeBase64(bytes);    return bts;}public static byte[] decode2Base64(String str) {    byte[] bts = Base64.decodeBase64(str);    return bts;}

public static String md5(String str) {    try {      MessageDigest digest = MessageDigest.getInstance("MD5");      return new String(digest.digest(str.getBytes()));    } catch (NoSuchAlgorithmException e) {      e.printStackTrace();    }    return "";}

public static byte[] sha1ToBytes(String str) {    try {      MessageDigest digest = MessageDigest.getInstance("SHA-1");      byte[] bts = digest.digest(str.getBytes());      return bts;    } catch (Exception e) {      e.printStackTrace();    }    return null;}

public static byte[] encryptMode(String keyStr, byte[] src) {    try {      // 生成密钥      SecretKey deskey = new SecretKeySpec(keyStr.getBytes(), "DESede");      // 加密      Cipher c1 = Cipher.getInstance("DESede");      c1.init(Cipher.ENCRYPT_MODE, deskey);      return c1.doFinal(src);    } catch (java.security.NoSuchAlgorithmException e1) {      e1.printStackTrace();    } catch (javax.crypto.NoSuchPaddingException e2) {      e2.printStackTrace();    } catch (java.lang.Exception e3) {      e3.printStackTrace();    }    return null;}public static byte[] decryptMode(String keyStr, byte[] src) {    try {      SecretKey deskey = new SecretKeySpec(keyStr.getBytes(), "DESede");      // 解密      Cipher c1 = Cipher.getInstance("DESede");      c1.init(Cipher.DECRYPT_MODE, deskey);      return c1.doFinal(src);    } catch (java.security.NoSuchAlgorithmException e1) {      e1.printStackTrace();    } catch (javax.crypto.NoSuchPaddingException e2) {      e2.printStackTrace();    } catch (java.lang.Exception e3) {      e3.printStackTrace();    }    return null;}

/*** 初始化公密钥* * @return* @throws Exception*/public static Map<String, Object> initKey() throws Exception {    KeyPairGenerator kpGenerator = KeyPairGenerator.getInstance("RSA");    kpGenerator.initialize(2048);    KeyPair keyPair = kpGenerator.generateKeyPair();    // 存储公钥    PublicKey publicKey = keyPair.getPublic();    // 存储密钥    PrivateKey privateKey = keyPair.getPrivate();    Map<String, Object> keyMap = new HashMap<String, Object>();    keyMap.put(PUBLIC_KEY, publicKey);    keyMap.put(PRIVATE_KEY, privateKey);    return keyMap;}/*** 取出公钥* * @param keyMap* @return*/public static String getPublicKey(Map<String, Object> keyMap) {    Key key = (Key) keyMap.get("RSAPublicKey");    return encode2Base64(new String(key.getEncoded()));}/*** 取出密钥* * @param keyMap* @return*/public static String getPrivateKey(Map<String, Object> keyMap) {    Key key = (Key) keyMap.get("RSAPrivateKey");    return encode2Base64(new String(key.getEncoded()));}/*** 公钥加密* * @param data* @param publicKey* @return* @throws Exception*/public static String encryptByPublicKey(String data, RSAPublicKey publicKey)  throws Exception {    Cipher cipher = Cipher.getInstance("RSA");    cipher.init(Cipher.ENCRYPT_MODE, publicKey);    // 模长    int key_len = publicKey.getModulus().bitLength() / 8;    // 加密数据长度 <= 模长-11    String[] datas = splitString(data, key_len - 11);    String mi = "";    // 如果明文长度大于模长-11则要分组加密    for (String s : datas) {      mi += bcd2Str(cipher.doFinal(s.getBytes()));    }    return mi;}/*** 私钥加密* * @param data* @param privateKey* @return* @throws Exception*/public static String encryptByPrivateKey(String data,  RSAPrivateKey privateKey) throws Exception {    Cipher cipher = Cipher.getInstance("RSA");    cipher.init(Cipher.ENCRYPT_MODE, privateKey);    // 模长    int key_len = privateKey.getModulus().bitLength() / 8;    // 加密数据长度 <= 模长-11    String[] datas = splitString(data, key_len - 11);    String mi = "";    // 如果明文长度大于模长-11则要分组加密    for (String s : datas) {      mi += bcd2Str(cipher.doFinal(s.getBytes()));    }    return mi;}/*** 私钥解密* * @param data* @param privateKey* @return* @throws Exception*/public static String decryptByPrivateKey(String data,  RSAPrivateKey privateKey) throws Exception {    Cipher cipher = Cipher.getInstance("RSA");    cipher.init(Cipher.DECRYPT_MODE, privateKey);    // 模长    int key_len = privateKey.getModulus().bitLength() / 8;    byte[] bytes = data.getBytes();    byte[] bcd = ASCII_To_BCD(bytes, bytes.length);    System.err.println(bcd.length);    // 如果密文长度大于模长则要分组解密    String ming = "";    byte[][] arrays = splitArray(bcd, key_len);    for (byte[] arr : arrays) {      ming += new String(cipher.doFinal(arr));    }    return ming;}/*** ASCII码转BCD码* */public static byte[] ASCII_To_BCD(byte[] ascii, int asc_len) {    byte[] bcd = new byte[asc_len / 2];    int j = 0;    for (int i = 0; i < (asc_len + 1) / 2; i++) {      bcd[i] = asc_to_bcd(ascii[j++]);      bcd[i] = (byte) (((j >= asc_len) ? 0x00 : asc_to_bcd(ascii[j++])) + (bcd[i] << 4));    }    return bcd;}public static byte asc_to_bcd(byte asc) {    byte bcd;    if ((asc >= '0') && (asc <= '9'))      bcd = (byte) (asc - '0');    else if ((asc >= 'A') && (asc <= 'F'))      bcd = (byte) (asc - 'A' + 10);    else if ((asc >= 'a') && (asc <= 'f'))      bcd = (byte) (asc - 'a' + 10);    else      bcd = (byte) (asc - 48);    return bcd;}/*** BCD转字符串*/public static String bcd2Str(byte[] bytes) {    char temp[] = new char[bytes.length * 2], val;    for (int i = 0; i < bytes.length; i++) {      val = (char) (((bytes[i] & 0xf0) >> 4) & 0x0f);      temp[i * 2] = (char) (val > 9 ? val + 'A' - 10 : val + '0');      val = (char) (bytes[i] & 0x0f);      temp[i * 2 + 1] = (char) (val > 9 ? val + 'A' - 10 : val + '0');    }    return new String(temp);}/*** 拆分字符串*/public static String[] splitString(String string, int len) {    int x = string.length() / len;    int y = string.length() % len;    int z = 0;    if (y != 0) {      z = 1;    }    String[] strings = new String[x + z];    String str = "";    for (int i = 0; i < x + z; i++) {      if (i == x + z - 1 && y != 0) {        str = string.substring(i * len, i * len + y);      } else {        str = string.substring(i * len, i * len + len);      }      strings[i] = str;    }    return strings;}/*** 拆分数组*/public static byte[][] splitArray(byte[] data, int len) {    int x = data.length / len;    int y = data.length % len;    int z = 0;    if (y != 0) {      z = 1;    }    byte[][] arrays = new byte[x + z][];    byte[] arr;    for (int i = 0; i < x + z; i++) {      arr = new byte[len];      if (i == x + z - 1 && y != 0) {        System.arraycopy(data, i * len, arr, 0, y);      } else {        System.arraycopy(data, i * len, arr, 0, len);      }      arrays[i] = arr;    }    return arrays;}