package com.security;

import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class SM4Utils {
	private String secretKey = "";
	
	private String iv = "";
	
	private boolean hexString = false;
	
	public SM4Utils() {
	}
	
	public String encryptData_ECB(String plainText) {
		try {
			SM4_Context ctx = new SM4_Context();
			ctx.isPadding = true;
			ctx.mode = SM4.SM4_ENCRYPT;
			
			byte[] keyBytes;
			if (hexString) {
				keyBytes = Util.hexStringToBytes(secretKey);
			} else {
				keyBytes = secretKey.getBytes();
			}
			
			SM4 sm4 = new SM4();
			sm4.sm4_setkey_enc(ctx, keyBytes);
			byte[] encrypted = sm4.sm4_crypt_ecb(ctx, plainText.getBytes("GBK"));
			String cipherText = new BASE64Encoder().encode(encrypted);
			if (cipherText != null && cipherText.trim().length() > 0) {
				Pattern p = Pattern.compile("\\s*|\t|\r|\n");
				Matcher m = p.matcher(cipherText);
				cipherText = m.replaceAll("");
			}
			return cipherText;
		} 
		catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}
	
	public String decryptData_ECB(String cipherText) {
		try {
			SM4_Context ctx = new SM4_Context();
			ctx.isPadding = true;
			ctx.mode = SM4.SM4_DECRYPT;
			
			byte[] keyBytes;
			if (hexString) {
				keyBytes = Util.hexStringToBytes(secretKey);
			} else {
				keyBytes = secretKey.getBytes();
			}
			
			SM4 sm4 = new SM4();
			sm4.sm4_setkey_dec(ctx, keyBytes);
			byte[] decrypted = sm4.sm4_crypt_ecb(ctx, new BASE64Decoder().decodeBuffer(cipherText));
			return new String(decrypted, "GBK");
		} 
		catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}
	
	public String encryptData_CBC(String plainText) {
		try {
			SM4_Context ctx = new SM4_Context();
			ctx.isPadding = true;
			ctx.mode = SM4.SM4_ENCRYPT;
			
			byte[] keyBytes;
			byte[] ivBytes;
			if (hexString) {
				keyBytes = Util.hexStringToBytes(secretKey);
				ivBytes = Util.hexStringToBytes(iv);
			}else{
				keyBytes = secretKey.getBytes();
				ivBytes = iv.getBytes();
			}
			
			SM4 sm4 = new SM4();
			sm4.sm4_setkey_enc(ctx, keyBytes);
			byte[] encrypted = sm4.sm4_crypt_cbc(ctx, ivBytes, plainText.getBytes("GBK"));
			String cipherText = new BASE64Encoder().encode(encrypted);
			if (cipherText != null && cipherText.trim().length() > 0) {
				Pattern p = Pattern.compile("\\s*|\t|\r|\n");
				Matcher m = p.matcher(cipherText);
				cipherText = m.replaceAll("");
			}
			return cipherText;
		} 
		catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}
	
	public String decryptData_CBC(String cipherText) {
		try {
			SM4_Context ctx = new SM4_Context();
			ctx.isPadding = true;
			ctx.mode = SM4.SM4_DECRYPT;
			
			byte[] keyBytes;
			byte[] ivBytes;
			if (hexString) {
				keyBytes = Util.hexStringToBytes(secretKey);
				ivBytes = Util.hexStringToBytes(iv);
			} else {
				keyBytes = secretKey.getBytes();
				ivBytes = iv.getBytes();
			}
			
			SM4 sm4 = new SM4();
			sm4.sm4_setkey_dec(ctx, keyBytes);
			byte[] decrypted = sm4.sm4_crypt_cbc(ctx, ivBytes, new BASE64Decoder().decodeBuffer(cipherText));
			return new String(decrypted, "GBK");
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}
	
	public static void main(String[] args) throws IOException  {
		String plainText = "abcd";
		
		SM4Utils sm4 = new SM4Utils();
		sm4.secretKey = "JeF8U9wHFOMfs2Y8";
		sm4.hexString = false;
		
		System.out.println("ECB模式");
		String cipherText = sm4.encryptData_ECB(plainText);
		System.out.println("密文: " + cipherText);
		System.out.println("");
		
		plainText = sm4.decryptData_ECB(cipherText);
		System.out.println("明文: " + plainText);
		System.out.println("");
		
		System.out.println("CBC模式");
		sm4.iv = "UISwD9fW6cFh9SNS";
		cipherText = sm4.encryptData_CBC(plainText);
		System.out.println("密文: " + cipherText);
		System.out.println("");
		
		plainText = sm4.decryptData_CBC(cipherText);
		System.out.println("明文: " + plainText);
	}
}
