com.siashan.toolkit.crypt.util.SmUtil Maven / Gradle / Ivy

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package com.siashan.toolkit.crypt.util;

import com.siashan.toolkit.crypt.CryptException;
import com.siashan.toolkit.crypt.asymmetric.SM2;
import org.bouncycastle.asn1.gm.GMNamedCurves;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.signers.StandardDSAEncoding;
import org.bouncycastle.util.Arrays;
import org.bouncycastle.util.encoders.Hex;

import java.io.IOException;
import java.math.BigInteger;

/**
 * SM国密算法工具类

 * 此工具类依赖org.bouncycastle:bcprov-jdk15to18
 *
 * @author siashan
 * @since 1.0.7
 */
public class SmUtil {

	/**
	 * SM2推荐曲线参数（来自https://github.com/ZZMarquis/gmhelper）
	 */
	public static final ECDomainParameters SM2_DOMAIN_PARAMS;

	private final static int RS_LEN = 32;

	static {
		SM2_DOMAIN_PARAMS = BCUtil.toDomainParams(GMNamedCurves.getByName(SM2.SM2_CURVE_NAME));
	}



	/**
	 * bc加解密使用旧标c1||c2||c3，此方法在加密后调用，将结果转化为c1||c3||c2
	 *
	 * @param c1c2c3             加密后的bytes，顺序为C1C2C3
	 * @param ecDomainParameters {@link ECDomainParameters}
	 * @return 加密后的bytes，顺序为C1C3C2
	 */
	public static byte[] changeC1C2C3ToC1C3C2(byte[] c1c2c3, ECDomainParameters ecDomainParameters) {
		// sm2p256v1的这个固定65。可看GMNamedCurves、ECCurve代码。
		final int c1Len = (ecDomainParameters.getCurve().getFieldSize() + 7) / 8 * 2 + 1;
		final int c3Len = 32; // new SM3Digest().getDigestSize();
		byte[] result = new byte[c1c2c3.length];
		System.arraycopy(c1c2c3, 0, result, 0, c1Len); // c1
		System.arraycopy(c1c2c3, c1c2c3.length - c3Len, result, c1Len, c3Len); // c3
		System.arraycopy(c1c2c3, c1Len, result, c1Len + c3Len, c1c2c3.length - c1Len - c3Len); // c2
		return result;
	}

	/**
	 * bc加解密使用旧标c1||c3||c2，此方法在解密前调用，将密文转化为c1||c2||c3再去解密
	 *
	 * @param c1c3c2             加密后的bytes，顺序为C1C3C2
	 * @param ecDomainParameters {@link ECDomainParameters}
	 * @return c1c2c3 加密后的bytes，顺序为C1C2C3
	 */
	public static byte[] changeC1C3C2ToC1C2C3(byte[] c1c3c2, ECDomainParameters ecDomainParameters) {
		// sm2p256v1的这个固定65。可看GMNamedCurves、ECCurve代码。
		final int c1Len = (ecDomainParameters.getCurve().getFieldSize() + 7) / 8 * 2 + 1;
		final int c3Len = 32; // new SM3Digest().getDigestSize();
		byte[] result = new byte[c1c3c2.length];
		System.arraycopy(c1c3c2, 0, result, 0, c1Len); // c1: 0->65
		System.arraycopy(c1c3c2, c1Len + c3Len, result, c1Len, c1c3c2.length - c1Len - c3Len); // c2
		System.arraycopy(c1c3c2, c1Len, result, c1c3c2.length - c3Len, c3Len); // c3
		return result;
	}

	/**
	 * BC的SM3withSM2签名得到的结果的rs是asn1格式的，这个方法转化成直接拼接r||s

	 * 来自：https://blog.csdn.net/pridas/article/details/86118774
	 *
	 * @param rsDer rs in asn1 format
	 * @return sign result in plain byte array
	 */
	public static byte[] rsAsn1ToPlain(byte[] rsDer) {
		final BigInteger[] decode;
		try {
			decode = StandardDSAEncoding.INSTANCE.decode(SM2_DOMAIN_PARAMS.getN(), rsDer);
		} catch (IOException e) {
			throw new CryptException(e);
		}

		final byte[] r = bigIntToFixedLengthBytes(decode[0]);
		final byte[] s = bigIntToFixedLengthBytes(decode[1]);

		return addAll(r, s);
	}

	/**
	 * BC的SM3withSM2验签需要的rs是asn1格式的，这个方法将直接拼接r||s的字节数组转化成asn1格式

	 * 来自：https://blog.csdn.net/pridas/article/details/86118774
	 *
	 * @param sign in plain byte array
	 * @return rs result in asn1 format
	 */
	public static byte[] rsPlainToAsn1(byte[] sign) {
		if (sign.length != RS_LEN * 2) {
			throw new CryptException("err rs. ");
		}
		BigInteger r = new BigInteger(1, Arrays.copyOfRange(sign, 0, RS_LEN));
		BigInteger s = new BigInteger(1, Arrays.copyOfRange(sign, RS_LEN, RS_LEN * 2));
		try {
			return StandardDSAEncoding.INSTANCE.encode(SM2_DOMAIN_PARAMS.getN(), r, s);
		} catch (IOException e) {
			throw new CryptException(e);
		}
	}


	// -------------------------------------------------------------------------------------------------------- Private method start

	/**
	 * BigInteger转固定长度bytes
	 *
	 * @param rOrS {@link BigInteger}
	 * @return 固定长度bytes
	 */
	private static byte[] bigIntToFixedLengthBytes(BigInteger rOrS) {
		// for sm2p256v1, n is 00fffffffeffffffffffffffffffffffff7203df6b21c6052b53bbf40939d54123,
		// r and s are the result of mod n, so they should be less than n and have length<=32
		byte[] rs = rOrS.toByteArray();
		if (rs.length == RS_LEN) {
			return rs;
		} else if (rs.length == RS_LEN + 1 && rs[0] == 0) {
			return Arrays.copyOfRange(rs, 1, RS_LEN + 1);
		} else if (rs.length < RS_LEN) {
			byte[] result = new byte[RS_LEN];
			Arrays.fill(result, (byte) 0);
			System.arraycopy(rs, 0, result, RS_LEN - rs.length, rs.length);
			return result;
		} else {
			throw new CryptException("Error rs: " + Hex.toHexString(rs));
		}
	}
	// -------------------------------------------------------------------------------------------------------- Private method end


	/**
	 * 将多个数组合并在一起

	 * 忽略null的数组
	 *
	 * @param arrays 数组集合
	 * @return 合并后的数组
	 */
	public static byte[] addAll(byte[]... arrays) {
		if (arrays.length == 1) {
			return arrays[0];
		}

		// 计算总长度
		int length = 0;
		for (byte[] array : arrays) {
			if (null != array) {
				length += array.length;
			}
		}

		final byte[] result = new byte[length];
		length = 0;
		for (byte[] array : arrays) {
			if (null != array) {
				System.arraycopy(array, 0, result, length, array.length);
				length += array.length;
			}
		}
		return result;
	}
}