目录
1.简要
2.开发环境及工具
3.后台密码加密部分
3.1加密代码
3.2 SM3加密类（Sm3crypto）
3.3国密SM3工具类（Sm3Utils）
3.4国密相关依赖包
4.登录认证部分
4.1前端部分关键代码
4.2后端login登录认证的关键代码
4.2.1.SM2公私钥（Sm2crypto ）
4.2.2SM2工具类（SM2Utils）
4.2.3SM2EngineExtend类
5.大功告成！
1.简要
本文结合个人实际代码，使用SM3加盐存储密码，并且使用SM2进行登录认证。主要有以下两个点需要了解：
1.新增用户时，将明文密码通过SM3加密后再加盐（随机生成）后形成密文存储在数据库中，同时我们也要将盐存在用户表的一个字段中（用于登录时密码的校验比对）。用户修改时不需要将盐进行更新存储。
2.登录认证时，在前端通过一个固定的公钥将账号和密码使用sm2进行加密后再传输到后端，后端通过一个固定的私钥将账号及密码进行解密，解密后的密码通过sm3加盐进行加密后与数据库中的密文进行比对认证。
3.以下所放的代码均为关键代码，并非全部代码，但足以供大家参考实现功能。
2.开发环境及工具
java,idea,mybatis-plus,spring boot,vue
3.后台密码加密部分
后台接收到密码明文，进行加密并保存。
3.1加密代码
用户表（SysUser）,密码字段（password）,放盐的字段（salt）
byte[] mySalt = Sm3crypto.getSalt();
//将盐用base64转化为字符串存到数据库中
sysUser.setSalt(Base64.getEncoder().encodeToString(mySalt));
//用密码sm3加密后再加盐，形成新的密码
sysUser.setPassword(Hex.toHexString(Sm3crypto.pwdSaltedHashValue(mySalt, sysUser.getPassword())));
this.save(sysUser);
3.2 SM3加密类（Sm3crypto）
import cn.stylefeng.guns.core.util.Sm3Utils;
import org.bouncycastle.crypto.digests.SM3Digest;
import org.bouncycastle.util.encoders.Hex;
import java.io.IOException;
import java.security.SecureRandom;
import java.util.Base64;
//SM3加密
public class Sm3crypto {
public static byte[] getSalt(){
/*
* 随机生成128位的随机数
*/
SecureRandom random = new SecureRandom();
byte bytes1[] = new byte[16];
random.nextBytes(bytes1);
return bytes1;
}
public static byte[] pwdSaltedHashValue(byte[] bytes1, String passwdString) {
//sm3加密密码
try {
passwdString = Sm3Utils.encodeSM3(passwdString);
} catch (IOException e) {
e.printStackTrace();
}
/*
* 加盐：即随机数和口令组合
*/
byte passwdbyte[]= arraycat(bytes1,passwdString.getBytes());
//SM3计算
SM3Digest mdDigest=new SM3Digest();
mdDigest.update(passwdbyte,0,passwdbyte.length);
byte[] result=new byte[mdDigest.getDigestSize()];
mdDigest.doFinal(result, 0);
return result;
}
/*
* 拼接buf1和buf2数组
*/
public static byte[] arraycat(byte[] buf1,byte[] buf2)
{
byte[] bufret=null;
int len1=0;
int len2=0;
if(buf1!=null)
len1=buf1.length;
if(buf2!=null)
len2=buf2.length;
if(len1+len2>0)
bufret=new byte[len1+len2];
if(len1>0)
System.arraycopy(buf1,0,bufret,0,len1);
if(len2>0)
System.arraycopy(buf2,0,bufret,len1,len2);
return bufret;
}
}
3.3国密SM3工具类（Sm3Utils）
import lombok.extern.slf4j.Slf4j;
import org.bouncycastle.util.Arrays;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
/**
* 国密SM3，消息摘要（MD5）
*
* @author Luke
*/
@Slf4j
public class Sm3Utils {
private static char[] chars = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
public static final byte[] IV = {0x73, (byte) 0x80, 0x16, 0x6f, 0x49, 0x14, (byte) 0xb2, (byte) 0xb9, 0x17, 0x24, 0x42,
(byte) 0xd7, (byte) 0xda, (byte) 0x8a, 0x06, 0x00, (byte) 0xa9, 0x6f, 0x30, (byte) 0xbc, (byte) 0x16, 0x31,
0x38, (byte) 0xaa, (byte) 0xe3, (byte) 0x8d, (byte) 0xee, 0x4d, (byte) 0xb0, (byte) 0xfb, 0x0e, 0x4e};
private static final Integer TJ_15 = Integer.valueOf("79cc4519", 16);
private static final Integer TJ_63 = Integer.valueOf("7a879d8a", 16);
private static final byte[] FirstPadding = {(byte) 0x80};
private static final byte[] ZeroPadding = {(byte) 0x00};
private static int T(int j) {
if (j >= 0 && j <= 15) {
return TJ_15.intValue();
} else if (j >= 16 && j <= 63) {
return TJ_63.intValue();
} else {
throw new RuntimeException("data invalid");
}
}
private static Integer FF(Integer x, Integer y, Integer z, int j) {
if (j >= 0 && j <= 15) {
return Integer.valueOf(x.intValue() ^ y.intValue() ^ z.intValue());
} else if (j >= 16 && j <= 63) {
return Integer.valueOf(
(x.intValue() & y.intValue()) | (x.intValue() & z.intValue()) | (y.intValue() & z.intValue()));
} else {
throw new RuntimeException("data invalid");
}
}
private static Integer GG(Integer x, Integer y, Integer z, int j) {
if (j >= 0 && j <= 15) {
return Integer.valueOf(x.intValue() ^ y.intValue() ^ z.intValue());
} else if (j >= 16 && j <= 63) {
return Integer.valueOf((x.intValue() & y.intValue()) | (~x.intValue() & z.intValue()));
} else {
throw new RuntimeException("data invalid");
}
}
private static Integer P0(Integer x) {
return Integer
.valueOf(x.intValue() ^ Integer.rotateLeft(x.intValue(), 9) ^ Integer.rotateLeft(x.intValue(), 17));
}
private static Integer P1(Integer x) {
return Integer.valueOf(x.intValue() ^ Integer.rotateLeft(x.intValue(), 15) ^ Integer.rotateLeft(x.intValue(), 23));
}
private static byte[] padding(byte[] source) throws IOException {
if (source.length >= 0x2000000000000000L) {
throw new RuntimeException("src data invalid.");
}
long l = source.length * 8;
long k = 448 - (l + 1) % 512;
if (k < 0) {
k = k + 512;
}
if (log.isDebugEnabled()) {
log.debug("k = " + k);
}
try (ByteArrayOutputStream baos = new ByteArrayOutputStream();) {
baos.write(source);
baos.write(FirstPadding);
long i = k - 7;
while (i > 0) {
baos.write(ZeroPadding);
i -= 8;
}
baos.write(long2bytes(l));
if (log.isDebugEnabled()) {
log.debug("paded size = " + baos.size());
}
return baos.toByteArray();
}
}
private static byte[] long2bytes(long l) {
byte[] bytes = new byte[8];
for (int i = 0; i < 8; i++) {
bytes[i] = (byte) (l >>> ((7 - i) * 8));
}
return bytes;
}
public static String encodeSM3(String source) throws IOException {
byte[] b = encodeSM3(source.getBytes());
return byteToHexString(b);
}
public static byte[] encodeSM3(byte[] source) throws IOException {
byte[] m1 = padding(source);
int n = m1.length / (512 / 8);
if (log.isDebugEnabled()) {
log.debug("n = " + n);
}
byte[] b;
byte[] vi = IV.clone();
byte[] vi1 = null;
for (int i = 0; i < n; i++) {
b = Arrays.copyOfRange(m1, i * 64, (i + 1) * 64);
vi1 = CF(vi, b);
vi = vi1;
}
return vi1;
}
private static byte[] CF(byte[] vi, byte[] bi) throws IOException {
int a, b, c, d, e, f, g, h;
a = toInteger(vi, 0);
b = toInteger(vi, 1);
c = toInteger(vi, 2);
d = toInteger(vi, 3);
e = toInteger(vi, 4);
f = toInteger(vi, 5);
g = toInteger(vi, 6);
h = toInteger(vi, 7);
int[] w = new int[68];
int[] w1 = new int[64];
for (int i = 0; i < 16; i++) {
w[i] = toInteger(bi, i);
}
for (int j = 16; j < 68; j++) {
w[j] = P1(w[j - 16] ^ w[j - 9] ^ Integer.rotateLeft(w[j - 3], 15)) ^ Integer.rotateLeft(w[j - 13], 7)
^ w[j - 6];
}
for (int j = 0; j < 64; j++) {
w1[j] = w[j] ^ w[j + 4];
}
int ss1, ss2, tt1, tt2;
for (int j = 0; j < 64; j++) {
ss1 = Integer.rotateLeft(Integer.rotateLeft(a, 12) + e + Integer.rotateLeft(T(j), j), 7);
ss2 = ss1 ^ Integer.rotateLeft(a, 12);
tt1 = FF(a, b, c, j) + d + ss2 + w1[j];
tt2 = GG(e, f, g, j) + h + ss1 + w[j];
d = c;
c = Integer.rotateLeft(b, 9);
b = a;
a = tt1;
h = g;
g = Integer.rotateLeft(f, 19);
f = e;
e = P0(tt2);
}
byte[] v = toByteArray(a, b, c, d, e, f, g, h);
for (int i = 0; i < v.length; i++) {
v[i] = (byte) (v[i] ^ vi[i]);
}
return v;
}
private static int toInteger(byte[] source, int index) {
StringBuilder valueStr = new StringBuilder("");
for (int i = 0; i < 4; i++) {
valueStr.append(chars[(byte) ((source[index * 4 + i] & 0xF0) >> 4)]);
valueStr.append(chars[(byte) (source[index * 4 + i] & 0x0F)]);
}
return Long.valueOf(valueStr.toString(), 16).intValue();
}
private static byte[] toByteArray(int a, int b, int c, int d, int e, int f, int g, int h) throws IOException {
try (ByteArrayOutputStream baos = new ByteArrayOutputStream(32);) {
baos.write(toByteArray(a));
baos.write(toByteArray(b));
baos.write(toByteArray(c));
baos.write(toByteArray(d));
baos.write(toByteArray(e));
baos.write(toByteArray(f));
baos.write(toByteArray(g));
baos.write(toByteArray(h));
return baos.toByteArray();
}
}
private static byte[] toByteArray(int i) {
byte[] byteArray = new byte[4];
byteArray[0] = (byte) (i >>> 24);
byteArray[1] = (byte) ((i & 0xFFFFFF) >>> 16);
byteArray[2] = (byte) ((i & 0xFFFF) >>> 8);
byteArray[3] = (byte) (i & 0xFF);
return byteArray;
}
private static String byteToHexString(byte[] bytes)
{
StringBuilder resultHexString = new StringBuilder();
String tempStr;
for (byte b: bytes) {
//这里需要对b与0xff做位与运算，
//若b为负数，强制转换将高位位扩展，导致错误，
//故需要高位清零
tempStr = Integer.toHexString(b & 0xff);
//若转换后的十六进制数字只有一位，
//则在前补"0"
if (tempStr.length() == 1) {
resultHexString.append(0).append(tempStr);
} else {
resultHexString.append(tempStr);
}
}
return resultHexString.toString();
}
private Sm3Utils() {
}
}
3.4国密相关依赖包
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk15on</artifactId>
<version>1.57</version>
</dependency>
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-ext-jdk15on</artifactId>
<version>1.57</version>
</dependency>
4.登录认证部分
4.1前端部分关键代码
1.npm安装国密：
npm install --save sm-crypto
2.vue中引用国密：
import SMCRYPTO from "sm-crypto";
3.在data中定义一下sm2：
data () {
return {
.
.
.
sm2: SMCRYPTO.sm2,
pubKey: "自己的SM2公钥"
}
},
4.登录时将账号密码使用sm2加密后传输到后台
//账号密码使用sm2加密
loginParams.account = this.sm2.doEncrypt(values.account, this.pubKey, 1);
loginParams.password = this.sm2.doEncrypt(values.password, this.pubKey, 1);
4.2后端login登录认证的关键代码
接收到前端的账号密码后进行处理，要将账号和密码利用SM2私钥进行解密，解密后的密码需要用sm3加密再加盐进行处理后与数据库的密码密文进行比对：
//账号解密
account = SM2Utils.decrypt(Sm2crypto.priKey,account,1);
SysUser sysUser = sysUserService.getUserByCount(account);
//用户不存在，账号或密码错误
if (ObjectUtil.isEmpty(sysUser)) {
LogManager.me().executeLoginLog(account, LogSuccessStatusEnum.FAIL.getCode(), AuthExceptionEnum.ACCOUNT_PWD_ERROR.getMessage());
throw new AuthException(AuthExceptionEnum.ACCOUNT_PWD_ERROR);
}
String passwordBcrypt = sysUser.getPassword();
//密码解密
password = SM2Utils.decrypt(Sm2crypto.priKey,password,1);
//获取用户表的盐
byte[] mySalt = Base64.getDecoder().decode(sysUser.getSalt());
//用密码sm3加密后再加盐，形成新的密码
password = Hex.toHexString(Sm3crypto.pwdSaltedHashValue(mySalt,password));
//验证账号密码是否正确
if (ObjectUtil.isEmpty(passwordBcrypt) || !password.equals(passwordBcrypt)) {
LogManager.me().executeLoginLog(sysUser.getAccount(), LogSuccessStatusEnum.FAIL.getCode(), AuthExceptionEnum.ACCOUNT_PWD_ERROR.getMessage());
throw new AuthException(AuthExceptionEnum.ACCOUNT_PWD_ERROR);
}
4.2.1.SM2公私钥（Sm2crypto ）
import cn.stylefeng.guns.core.sm2.SM2KeyPair;
import cn.stylefeng.guns.core.sm2.SM2Utils;
import org.springframework.stereotype.Component;
import java.lang.reflect.Field;
import java.util.Objects;
@Component
public class Sm2crypto {
public static String pubKey = "自己的SM2公钥，与前端加密用的公钥一样";
public static String priKey = "自己的SM2私钥";
}
4.2.2SM2工具类（SM2Utils）
import lombok.extern.slf4j.Slf4j;
import org.bouncycastle.asn1.gm.GMNamedCurves;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
import org.bouncycastle.crypto.generators.ECKeyPairGenerator;
import org.bouncycastle.crypto.params.*;
import org.bouncycastle.math.ec.ECPoint;
import org.bouncycastle.util.encoders.Hex;
import java.math.BigInteger;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
@Slf4j
public class SM2Utils {
/**
* SM2加密算法
* @param publicKey 公钥
* @param data 待加密的数据
* @return 密文，BC库产生的密文带由04标识符，与非BC库对接时需要去掉开头的04
*/
public static String encrypt(String publicKey, String data){
// 按国密排序标准加密
return encrypt(publicKey, data, SM2EngineExtend.CIPHERMODE_NORM);
}
/**
* SM2加密算法
* @param publicKey 公钥
* @param data 待加密的数据
* @param cipherMode 密文排列方式0-C1C2C3；1-C1C3C2；
* @return 密文，BC库产生的密文带由04标识符，与非BC库对接时需要去掉开头的04
*/
public static String encrypt(String publicKey, String data, int cipherMode){
// 获取一条SM2曲线参数
X9ECParameters sm2ECParameters = GMNamedCurves.getByName("sm2p256v1");
// 构造ECC算法参数，曲线方程、椭圆曲线G点、大整数N
ECDomainParameters domainParameters = new ECDomainParameters(sm2ECParameters.getCurve(), sm2ECParameters.getG(), sm2ECParameters.getN());
//提取公钥点
ECPoint pukPoint = sm2ECParameters.getCurve().decodePoint(Hex.decode(publicKey));
// 公钥前面的02或者03表示是压缩公钥，04表示未压缩公钥, 04的时候，可以去掉前面的04
ECPublicKeyParameters publicKeyParameters = new ECPublicKeyParameters(pukPoint, domainParameters);
SM2EngineExtend sm2Engine = new SM2EngineExtend();
// 设置sm2为加密模式
sm2Engine.init(true, cipherMode, new ParametersWithRandom(publicKeyParameters, new SecureRandom()));
byte[] arrayOfBytes = null;
try {
byte[] in = data.getBytes();
arrayOfBytes = sm2Engine.processBlock(in, 0, in.length);
} catch (Exception e) {
log.error("SM2加密时出现异常:{}", e.getMessage(), e);
}
return Hex.toHexString(arrayOfBytes);
}
/**
* 获取sm2密钥对
* BC库使用的公钥=64个字节+1个字节（04标志位），BC库使用的私钥=32个字节
* SM2秘钥的组成部分有 私钥D 、公钥X 、 公钥Y , 他们都可以用长度为64的16进制的HEX串表示，
* <br/>SM2公钥并不是直接由X+Y表示 , 而是额外添加了一个头，当启用压缩时:公钥=有头+公钥X ，即省略了公钥Y的部分
* @param compressed 是否压缩公钥（加密解密都使用BC库才能使用压缩）
* @return
*/
public static SM2KeyPair getSm2Keys(boolean compressed){
//获取一条SM2曲线参数
X9ECParameters sm2ECParameters = GMNamedCurves.getByName("sm2p256v1");
//构造domain参数
ECDomainParameters domainParameters = new ECDomainParameters(sm2ECParameters.getCurve(), sm2ECParameters.getG(), sm2ECParameters.getN());
//1.创建密钥生成器
ECKeyPairGenerator keyPairGenerator = new ECKeyPairGenerator();
//2.初始化生成器,带上随机数
try {
keyPairGenerator.init(new ECKeyGenerationParameters(domainParameters, SecureRandom.getInstance("SHA1PRNG")));
} catch (NoSuchAlgorithmException e) {
log.error("生成公私钥对时出现异常:", e);
}
//3.生成密钥对
AsymmetricCipherKeyPair asymmetricCipherKeyPair = keyPairGenerator.generateKeyPair();
ECPublicKeyParameters publicKeyParameters = (ECPublicKeyParameters)asymmetricCipherKeyPair.getPublic();
ECPoint ecPoint = publicKeyParameters.getQ();
// 把公钥放入map中,默认压缩公钥
// 公钥前面的02或者03表示是压缩公钥,04表示未压缩公钥,04的时候,可以去掉前面的04
String publicKey = Hex.toHexString(ecPoint.getEncoded(compressed));
ECPrivateKeyParameters privateKeyParameters = (ECPrivateKeyParameters) asymmetricCipherKeyPair.getPrivate();
BigInteger intPrivateKey = privateKeyParameters.getD();
// 把私钥放入map中
String privateKey = intPrivateKey.toString(16);
return new SM2KeyPair(publicKey, privateKey);
}
/**
* SM2解密算法
* @param privateKey 私钥
* @param cipherData 密文数据
* @return
*/
public static String decrypt(String privateKey, String cipherData) {
// // 按国密排序标准解密
return decrypt(privateKey, cipherData, SM2EngineExtend.CIPHERMODE_NORM);
}
/**
* SM2解密算法
* @param privateKey 私钥
* @param cipherData 密文数据
* @param cipherMode 密文排列方式0-C1C2C3；1-C1C3C2；
* @return
*/
public static String decrypt(String privateKey, String cipherData, int cipherMode) {
// 使用BC库加解密时密文以04开头，传入的密文前面没有04则补上
if (!cipherData.startsWith("04")){
cipherData = "04" + cipherData;
}
byte[] cipherDataByte = Hex.decode(cipherData);
//获取一条SM2曲线参数
X9ECParameters sm2ECParameters = GMNamedCurves.getByName("sm2p256v1");
//构造domain参数
ECDomainParameters domainParameters = new ECDomainParameters(sm2ECParameters.getCurve(), sm2ECParameters.getG(), sm2ECParameters.getN());
BigInteger privateKeyD = new BigInteger(privateKey, 16);
ECPrivateKeyParameters privateKeyParameters = new ECPrivateKeyParameters(privateKeyD, domainParameters);
SM2EngineExtend sm2Engine = new SM2EngineExtend();
// 设置sm2为解密模式
sm2Engine.init(false, cipherMode, privateKeyParameters);
String result = "";
try {
byte[] arrayOfBytes = sm2Engine.processBlock(cipherDataByte, 0, cipherDataByte.length);
return new String(arrayOfBytes);
} catch (Exception e) {
log.error("SM2解密时出现异常:{}", e.getMessage(), e);
}
return result;
}
}
4.2.3SM2EngineExtend类
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.digests.SM3Digest;
import org.bouncycastle.crypto.params.*;
import org.bouncycastle.math.ec.ECConstants;
import org.bouncycastle.math.ec.ECFieldElement;
import org.bouncycastle.math.ec.ECPoint;
import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.BigIntegers;
import java.math.BigInteger;
import java.security.SecureRandom;
public class SM2EngineExtend {
private final Digest digest;
/**是否为加密模式*/
private boolean forEncryption;
private ECKeyParameters ecKey;
private ECDomainParameters ecParams;
private int curveLength;
private SecureRandom random;
/**密文排序方式*/
private int cipherMode;
/**BC库默认排序方式-C1C2C3*/
public static int CIPHERMODE_BC = 0;
/**国密标准排序方式-C1C3C2*/
public static int CIPHERMODE_NORM = 1;
public SM2EngineExtend() {
this(new SM3Digest());
}
public SM2EngineExtend(Digest digest) {
this.digest = digest;
}
/**
* 设置密文排序方式
* @param cipherMode
*/
public void setCipherMode(int cipherMode){
this.cipherMode = cipherMode;
}
/**
* 默认初始化方法，使用国密排序标准
* @param forEncryption - 是否以加密模式初始化
* @param param - 曲线参数
*/
public void init(boolean forEncryption, CipherParameters param) {
init(forEncryption, CIPHERMODE_NORM, param);
}
/**
* 默认初始化方法，使用国密排序标准
* @param forEncryption 是否以加密模式初始化
* @param cipherMode 加密数据排列模式：1-标准排序；0-BC默认排序
* @param param 曲线参数
*/
public void init(boolean forEncryption, int cipherMode, CipherParameters param) {
this.forEncryption = forEncryption;
this.cipherMode = cipherMode;
if (forEncryption) {
ParametersWithRandom rParam = (ParametersWithRandom) param;
ecKey = (ECKeyParameters) rParam.getParameters();
ecParams = ecKey.getParameters();
ECPoint s = ((ECPublicKeyParameters) ecKey).getQ().multiply(ecParams.getH());
if (s.isInfinity()) {
throw new IllegalArgumentException("invalid key: [h]Q at infinity");
}
random = rParam.getRandom();
} else {
ecKey = (ECKeyParameters) param;
ecParams = ecKey.getParameters();
}
curveLength = (ecParams.getCurve().getFieldSize() + 7) / 8;
}
/**
* 加密或解密输入数据
* @param in
* @param inOff
* @param inLen
* @return
* @throws InvalidCipherTextException
*/
public byte[] processBlock( byte[] in, int inOff, int inLen) throws InvalidCipherTextException {
if (forEncryption) {
// 加密
return encrypt(in, inOff, inLen);
} else {
return decrypt(in, inOff, inLen);
}
}
/**
* 加密实现，根据cipherMode输出指定排列的结果，默认按标准方式排列
* @param in
* @param inOff
* @param inLen
* @return
* @throws InvalidCipherTextException
*/
private byte[] encrypt(byte[] in, int inOff, int inLen)
throws InvalidCipherTextException {
byte[] c2 = new byte[inLen];
System.arraycopy(in, inOff, c2, 0, c2.length);
byte[] c1;
ECPoint kPB;
do {
BigInteger k = nextK();
ECPoint c1P = ecParams.getG().multiply(k).normalize();
c1 = c1P.getEncoded(false);
kPB = ((ECPublicKeyParameters) ecKey).getQ().multiply(k).normalize();
kdf(digest, kPB, c2);
}
while (notEncrypted(c2, in, inOff));
byte[] c3 = new byte[digest.getDigestSize()];
addFieldElement(digest, kPB.getAffineXCoord());
digest.update(in, inOff, inLen);
addFieldElement(digest, kPB.getAffineYCoord());
digest.doFinal(c3, 0);
if (cipherMode == CIPHERMODE_NORM){
return Arrays.concatenate(c1, c3, c2);
}
return Arrays.concatenate(c1, c2, c3);
}
/**
* 解密实现，默认按标准排列方式解密，解密时解出c2部分原文并校验c3部分
* @param in
* @param inOff
* @param inLen
* @return
* @throws InvalidCipherTextException
*/
private byte[] decrypt(byte[] in, int inOff, int inLen)
throws InvalidCipherTextException {
byte[] c1 = new byte[curveLength * 2 + 1];
System.arraycopy(in, inOff, c1, 0, c1.length);
ECPoint c1P = ecParams.getCurve().decodePoint(c1);
ECPoint s = c1P.multiply(ecParams.getH());
if (s.isInfinity()) {
throw new InvalidCipherTextException("[h]C1 at infinity");
}
c1P = c1P.multiply(((ECPrivateKeyParameters) ecKey).getD()).normalize();
byte[] c2 = new byte[inLen - c1.length - digest.getDigestSize()];
if (cipherMode == CIPHERMODE_BC) {
System.arraycopy(in, inOff + c1.length, c2, 0, c2.length);
}else{
// C1 C3 C2
System.arraycopy(in, inOff + c1.length + digest.getDigestSize(), c2, 0, c2.length);
}
kdf(digest, c1P, c2);
byte[] c3 = new byte[digest.getDigestSize()];
addFieldElement(digest, c1P.getAffineXCoord());
digest.update(c2, 0, c2.length);
addFieldElement(digest, c1P.getAffineYCoord());
digest.doFinal(c3, 0);
int check = 0;
// 检查密文输入值C3部分和由摘要生成的C3是否一致
if (cipherMode == CIPHERMODE_BC) {
for (int i = 0; i != c3.length; i++) {
check |= c3[i] ^ in[c1.length + c2.length + i];
}
}else{
for (int i = 0; i != c3.length; i++) {
check |= c3[i] ^ in[c1.length + i];
}
}
clearBlock(c1);
clearBlock(c3);
if (check != 0) {
clearBlock(c2);
throw new InvalidCipherTextException("invalid cipher text");
}
return c2;
}
private boolean notEncrypted(byte[] encData, byte[] in, int inOff) {
for (int i = 0; i != encData.length; i++) {
if (encData[i] != in[inOff]) {
return false;
}
}
return true;
}
private void kdf(Digest digest, ECPoint c1, byte[] encData) {
int ct = 1;
int v = digest.getDigestSize();
byte[] buf = new byte[digest.getDigestSize()];
int off = 0;
for (int i = 1; i <= ((encData.length + v - 1) / v); i++) {
addFieldElement(digest, c1.getAffineXCoord());
addFieldElement(digest, c1.getAffineYCoord());
digest.update((byte) (ct >> 24));
digest.update((byte) (ct >> 16));
digest.update((byte) (ct >> 8));
digest.update((byte) ct);
digest.doFinal(buf, 0);
if (off + buf.length < encData.length) {
xor(encData, buf, off, buf.length);
} else {
xor(encData, buf, off, encData.length - off);
}
off += buf.length;
ct++;
}
}
private void xor(byte[] data, byte[] kdfOut, int dOff, int dRemaining) {
for (int i = 0; i != dRemaining; i++) {
data[dOff + i] ^= kdfOut[i];
}
}
private BigInteger nextK() {
int qBitLength = ecParams.getN().bitLength();
BigInteger k;
do {
k = new BigInteger(qBitLength, random);
}
while (k.equals(ECConstants.ZERO) || k.compareTo(ecParams.getN()) >= 0);
return k;
}
private void addFieldElement(Digest digest, ECFieldElement v) {
byte[] p = BigIntegers.asUnsignedByteArray(curveLength, v.toBigInteger());
digest.update(p, 0, p.length);
}
/**
* clear possible sensitive data
*/
private void clearBlock(
byte[] block) {
for (int i = 0; i != block.length; i++) {
block[i] = 0;
}
}
}
5.大功告成！
