JAVA中常用的加密算法总结

来源：互联网发布：帝国cms 二级目录编辑：程序博客网时间：2024/06/05 16:16

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

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

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

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

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

/**     * 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。

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