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。
来源:CSDN
作者:wz_微臣
链接:https://blog.csdn.net/chenbing81/article/details/51914151