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package com.dahuatech.hutool.crypto.asymmetric;

import com.dahuatech.hutool.core.util.ObjectUtil;
import com.dahuatech.hutool.crypto.CryptoException;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.CryptoServicesRegistrar;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.digests.SM3Digest;
import org.bouncycastle.crypto.params.*;
import org.bouncycastle.math.ec.*;
import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.BigIntegers;
import org.bouncycastle.util.Memoable;
import org.bouncycastle.util.Pack;

import java.math.BigInteger;
import java.util.Random;

/**
 * SM2加密解密引擎,来自Bouncy Castle库的SM2Engine类改造
* SM2加密后的数据格式为(两种模式): * *
 * curve(C1) | data(C2) | digest(C3)
 * curve(C1) | digest(C3) | data(C2)
 * 
* * @author looly, bouncycastle * @since 4.5.0 */ public class SM2Engine { private final Digest digest; private boolean forEncryption; private ECKeyParameters ecKey; private ECDomainParameters ecParams; private int curveLength; private Random random; /** 加密解密模式 */ private SM2Mode mode; /** 构造 */ public SM2Engine() { this(new SM3Digest()); } /** * 构造 * * @param mode SM2密钥生成模式,可选C1C2C3和C1C3C2 */ public SM2Engine(SM2Mode mode) { this(new SM3Digest(), mode); } /** * 构造 * * @param digest 摘要算法啊 */ public SM2Engine(Digest digest) { this(digest, null); } /** * 构造 * * @param digest 摘要算法啊 * @param mode SM2密钥生成模式,可选C1C2C3和C1C3C2 */ public SM2Engine(Digest digest, SM2Mode mode) { this.digest = digest; this.mode = ObjectUtil.defaultIfNull(mode, SM2Mode.C1C3C2); } /** * 初始化引擎 * * @param forEncryption 是否为加密模式 * @param param {@link CipherParameters},此处应为{@link ParametersWithRandom}(加密时)或{@link * ECKeyParameters}(解密时) */ public void init(boolean forEncryption, CipherParameters param) { this.forEncryption = forEncryption; if (param instanceof ParametersWithRandom) { final ParametersWithRandom rParam = (ParametersWithRandom) param; this.ecKey = (ECKeyParameters) rParam.getParameters(); this.random = rParam.getRandom(); } else { this.ecKey = (ECKeyParameters) param; } this.ecParams = this.ecKey.getParameters(); if (forEncryption) { // 检查曲线点 final ECPoint ecPoint = ((ECPublicKeyParameters) ecKey).getQ().multiply(ecParams.getH()); if (ecPoint.isInfinity()) { throw new IllegalArgumentException("invalid key: [h]Q at infinity"); } // 检查随机参数 if (null == this.random) { this.random = CryptoServicesRegistrar.getSecureRandom(); } } // 曲线位长度 this.curveLength = (this.ecParams.getCurve().getFieldSize() + 7) / 8; } /** * 处理块,包括加密和解密 * * @param in 数据 * @param inOff 数据开始位置 * @param inLen 数据长度 * @return 结果 */ public byte[] processBlock(byte[] in, int inOff, int inLen) { if (forEncryption) { return encrypt(in, inOff, inLen); } else { return decrypt(in, inOff, inLen); } } /** * 设置加密类型 * * @param mode {@link SM2Mode} * @return this */ public SM2Engine setMode(SM2Mode mode) { this.mode = mode; return this; } protected ECMultiplier createBasePointMultiplier() { return new FixedPointCombMultiplier(); } /** * 加密 * * @param in 数据 * @param inOff 位置 * @param inLen 长度 * @return 密文 */ private byte[] encrypt(byte[] in, int inOff, int inLen) { // 加密数据 byte[] c2 = new byte[inLen]; System.arraycopy(in, inOff, c2, 0, c2.length); final ECMultiplier multiplier = createBasePointMultiplier(); byte[] c1; ECPoint kPB; BigInteger k; do { k = nextK(); // 产生随机数计算出曲线点C1 c1 = multiplier.multiply(ecParams.getG(), k).normalize().getEncoded(false); kPB = ((ECPublicKeyParameters) ecKey).getQ().multiply(k).normalize(); kdf(kPB, c2); } while (notEncrypted(c2, in, inOff)); // 杂凑值,效验数据 byte[] c3 = new byte[digest.getDigestSize()]; addFieldElement(kPB.getAffineXCoord()); this.digest.update(in, inOff, inLen); addFieldElement(kPB.getAffineYCoord()); this.digest.doFinal(c3, 0); // 按照对应模式输出结果 switch (mode) { case C1C3C2: return Arrays.concatenate(c1, c3, c2); default: return Arrays.concatenate(c1, c2, c3); } } // --------------------------------------------------------------------------------------------------- Private method start /** * 解密,只支持私钥解密 * * @param in 密文 * @param inOff 位置 * @param inLen 长度 * @return 解密后的内容 */ private byte[] decrypt(byte[] in, int inOff, int inLen) { // 获取曲线点 final byte[] c1 = new byte[this.curveLength * 2 + 1]; System.arraycopy(in, inOff, c1, 0, c1.length); ECPoint c1P = this.ecParams.getCurve().decodePoint(c1); if (c1P.multiply(this.ecParams.getH()).isInfinity()) { throw new CryptoException("[h]C1 at infinity"); } c1P = c1P.multiply(((ECPrivateKeyParameters) ecKey).getD()).normalize(); final int digestSize = this.digest.getDigestSize(); // 解密C2数据 final byte[] c2 = new byte[inLen - c1.length - digestSize]; if (SM2Mode.C1C3C2 == this.mode) { // C2位于第三部分 System.arraycopy(in, inOff + c1.length + digestSize, c2, 0, c2.length); } else { // C2位于第二部分 System.arraycopy(in, inOff + c1.length, c2, 0, c2.length); } kdf(c1P, c2); // 使用摘要验证C2数据 final byte[] c3 = new byte[digestSize]; addFieldElement(c1P.getAffineXCoord()); this.digest.update(c2, 0, c2.length); addFieldElement(c1P.getAffineYCoord()); this.digest.doFinal(c3, 0); int check = 0; for (int i = 0; i != c3.length; i++) { check |= c3[i] ^ in[inOff + c1.length + ((SM2Mode.C1C3C2 == this.mode) ? 0 : c2.length) + i]; } Arrays.fill(c1, (byte) 0); Arrays.fill(c3, (byte) 0); if (check != 0) { Arrays.fill(c2, (byte) 0); throw new CryptoException("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 + i]) { return false; } } return true; } /** * 解密数据 * * @param c1 c1点 * @param encData 密文 */ private void kdf(ECPoint c1, byte[] encData) { final Digest digest = this.digest; int digestSize = digest.getDigestSize(); byte[] buf = new byte[Math.max(4, digestSize)]; int off = 0; Memoable memo = null; Memoable copy = null; if (digest instanceof Memoable) { addFieldElement(c1.getAffineXCoord()); addFieldElement(c1.getAffineYCoord()); memo = (Memoable) digest; copy = memo.copy(); } int ct = 0; while (off < encData.length) { if (memo != null) { memo.reset(copy); } else { addFieldElement(c1.getAffineXCoord()); addFieldElement(c1.getAffineYCoord()); } Pack.intToBigEndian(++ct, buf, 0); digest.update(buf, 0, 4); digest.doFinal(buf, 0); int xorLen = Math.min(digestSize, encData.length - off); xor(encData, buf, off, xorLen); off += xorLen; } } /** * 异或 * * @param data 数据 * @param kdfOut kdf输出值 * @param dOff d偏移 * @param dRemaining d剩余 */ private void xor(byte[] data, byte[] kdfOut, int dOff, int dRemaining) { for (int i = 0; i != dRemaining; i++) { data[dOff + i] ^= kdfOut[i]; } } /** * 下一个K值 * * @return K值 */ private BigInteger nextK() { final int qBitLength = this.ecParams.getN().bitLength(); BigInteger k; do { k = new BigInteger(qBitLength, this.random); } while (k.equals(ECConstants.ZERO) || k.compareTo(this.ecParams.getN()) >= 0); return k; } /** * 增加字段节点 * * @param v 节点 */ private void addFieldElement(ECFieldElement v) { final byte[] p = BigIntegers.asUnsignedByteArray(this.curveLength, v.toBigInteger()); this.digest.update(p, 0, p.length); } /** * SM2算法模式
* 在SM2算法中,C1C2C3为旧标准模式,C1C3C2为新标准模式 * * @author looly */ public enum SM2Mode { C1C2C3, C1C3C2 } // --------------------------------------------------------------------------------------------------- Private method start }




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