本文实例总结了Java常用加密算法。分享给大家供大家参考，具体如下：
项目中第一次深入地了解到加密算法的使用，现第一阶段结束，将使用到的加密算法和大家分享一下：
首先还是先给大家普及一下常用加密算法的基础知识
基本的单向加密算法
BASE64 严格地说，属于编码格式，而非加密算法
MD5(Message Digest algorithm 5，信息摘要算法)
SHA(Secure Hash Algorithm，安全散列算法)
复杂的加密算法
RSA(算法的名字以发明者的名字命名：Ron Rivest, AdiShamir 和Leonard Adleman)
DES/3DES(Digital Signature Algorithm，数字签名)
国密算法
SM2/SM4(是由国家密码管理局编制的一种商用密码分组标准对称算法)
使用方法：
base64
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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;} |
MD5
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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 "";} |
SHA-1
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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;} |
DES/3DES
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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;} |
RSA
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/*** 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;} |
以上就是本次项目中用到的加密算法，需要注意的是编码格式一定要双方统一 ，如果不一致则加解密不成功。
希望本文所述对大家java程序设计有所帮助。
原文链接：http://blog.csdn.net/chenbing81/article/details/51914151
