对称加密算法介绍
- 常见算法
- DES：Data Encryption Standard，即数据加密标准
- AES：Advanced Encryption Standard，高级加密标准
开发中一般优先使用AES
-
特点：可以自己指定秘钥，可逆，有秘钥即可破解
-
底层机制：操作二进制
DES加密和解密
参考：
https://docs.oracle.com/javase/8/docs/api/javax/crypto/Cipher.html
对称加密解密三部曲：
1. 创建cipher对象
2. 初始化cipher
3. 加密和解密
class DESCrypt {
/**
* des加密
*/
fun encrypt(input: String, password: String): ByteArray {
//1. 创建cipher对象
val cipher = Cipher.getInstance("DES")
//2. 初始化cipher
val kf = SecretKeyFactory.getInstance("DES")
//自己指定的秘钥
val keySpec = DESKeySpec(password.toByteArray())
val key: Key? = kf.generateSecret(keySpec)
cipher.init(Cipher.ENCRYPT_MODE, key)
//3. 加密和解密
return cipher.doFinal(input.toByteArray());
}
/**
* des解密
*/
fun decrypt(input: ByteArray, password: String): ByteArray {
//1. 创建cipher对象
val cipher = Cipher.getInstance("DES")
//2. 初始化cipher
val kf = SecretKeyFactory.getInstance("DES")
//自己指定的秘钥
val keySpec = DESKeySpec(password.toByteArray())
val key: Key? = kf.generateSecret(keySpec)
cipher.init(Cipher.DECRYPT_MODE, key)
//3. 加密和解密
return cipher.doFinal(input);
}
}
fun main() {
//原文
val input = "欢迎光临"
val password = "1234567890"//秘钥，des长度大于等于8位
// val array = input.toByteArray()
val encrypt = DESCrypt().encrypt(input, password)
val decrypt = DESCrypt().decrypt(encrypt, password)
println("des加密 = ${String(encrypt)}")
println("des解密 = ${String(decrypt)}")
}
使用Base64
package com.hongx.kotlin.crypt
import java.security.Key
import javax.crypto.Cipher
import javax.crypto.SecretKeyFactory
import javax.crypto.spec.DESKeySpec
class DESCrypt {
/**
* des加密
*/
fun encrypt(input: String, password: String): String {
//1. 创建cipher对象
val cipher = Cipher.getInstance("DES")
//2. 初始化cipher
val kf = SecretKeyFactory.getInstance("DES")
//自己指定的秘钥
val keySpec = DESKeySpec(password.toByteArray())
val key: Key? = kf.generateSecret(keySpec)
cipher.init(Cipher.ENCRYPT_MODE, key)
//3. 加密和解密
val encrypt = cipher.doFinal(input.toByteArray());
// return String(encrypt)
return Base64Util.encode(encrypt)
}
/**
* des解密
*/
fun decrypt(input: String, password: String): String {
//1. 创建cipher对象
val cipher = Cipher.getInstance("DES")
//2. 初始化cipher
val kf = SecretKeyFactory.getInstance("DES")
//自己指定的秘钥
val keySpec = DESKeySpec(password.toByteArray())
val key: Key? = kf.generateSecret(keySpec)
cipher.init(Cipher.DECRYPT_MODE, key)
//3. 加密和解密
// val decrypt = cipher.doFinal(input.toByteArray())
val decrypt = cipher.doFinal(Base64Util.decode(input))
return String(decrypt)
}
}
fun main() {
//原文
val input = "欢迎光临"
val password = "1234567890"//秘钥，des长度大于等于8位
val encrypt = DESCrypt().encrypt(input, password)
val decrypt = DESCrypt().decrypt(encrypt, password)
println("des加密 = $encrypt")
println("des解密 = $decrypt")
}
import java.io.ByteArrayOutputStream;
public class Base64Util {
private static final 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};
private Base64Util() {
}
/**
* 将字节数组编码为字符串
*/
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();
}
/**
* 将base64字符串解码为字节数组
*/
public static byte[] decode(String str) {
byte[] data = str.getBytes();
int len = data.length;
ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
int i = 0;
int b1, b2, b3, b4;
while (i < len) {
/* b1 */
do {
b1 = base64DecodeChars[data[i++]];
} while (i < len && b1 == -1);
if (b1 == -1) {
break;
}
/* b2 */
do {
b2 = base64DecodeChars[data[i++]];
} while (i < len && b2 == -1);
if (b2 == -1) {
break;
}
buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));
/* b3 */
do {
b3 = data[i++];
if (b3 == 61) {
return buf.toByteArray();
}
b3 = base64DecodeChars[b3];
} while (i < len && b3 == -1);
if (b3 == -1) {
break;
}
buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));
/* b4 */
do {
b4 = data[i++];
if (b4 == 61) {
return buf.toByteArray();
}
b4 = base64DecodeChars[b4];
} while (i < len && b4 == -1);
if (b4 == -1) {
break;
}
buf.write((int) (((b3 & 0x03) << 6) | b4));
}
return buf.toByteArray();
}
}
