SM2的非对称加解密java工具类
maven依赖
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk15on</artifactId>
<version>1.54</version>
</dependency>
java实现如下
import java.math.BigInteger;
import java.security.SecureRandom;
import java.util.Arrays;
import org.bouncycastle.crypto.DerivationFunction;
import org.bouncycastle.crypto.digests.SHA256Digest;
import org.bouncycastle.crypto.digests.ShortenedDigest;
import org.bouncycastle.crypto.generators.KDF1BytesGenerator;
import org.bouncycastle.crypto.params.ISO18033KDFParameters;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.math.ec.ECPoint;
/**
* <B>说 明<B/>:SM2的非对称加解密工具类，椭圆曲线方程为：y^2=x^3+ax+b 使用Fp-256
*/
public class SM2Util {
/** 素数p */
private static final BigInteger p = new BigInteger("FFFFFFFE" + "FFFFFFFF"
+ "FFFFFFFF" + "FFFFFFFF" + "FFFFFFFF" + "00000000" + "FFFFFFFF"
+ "FFFFFFFF", 16);
/** 系数a */
private static final BigInteger a = new BigInteger("FFFFFFFE" + "FFFFFFFF"
+ "FFFFFFFF" + "FFFFFFFF" + "FFFFFFFF" + "00000000" + "FFFFFFFF"
+ "FFFFFFFC", 16);
/** 系数b */
private static final BigInteger b = new BigInteger("28E9FA9E" + "9D9F5E34"
+ "4D5A9E4B" + "CF6509A7" + "F39789F5" + "15AB8F92" + "DDBCBD41"
+ "4D940E93", 16);
/** 坐标x */
private static final BigInteger xg = new BigInteger("32C4AE2C" + "1F198119"
+ "5F990446" + "6A39C994" + "8FE30BBF" + "F2660BE1" + "715A4589"
+ "334C74C7", 16);
/** 坐标y */
private static final BigInteger yg = new BigInteger("BC3736A2" + "F4F6779C"
+ "59BDCEE3" + "6B692153" + "D0A9877C" + "C62A4740" + "02DF32E5"
+ "2139F0A0", 16);
/** 基点G, G=(xg,yg),其介记为n */
private static final BigInteger n = new BigInteger("FFFFFFFE" + "FFFFFFFF"
+ "FFFFFFFF" + "FFFFFFFF" + "7203DF6B" + "21C6052B" + "53BBF409"
+ "39D54123", 16);
private static SecureRandom random = new SecureRandom();
private ECCurve.Fp curve;
private ECPoint G;
public static String printHexString(byte[] b) {
StringBuilder builder = new StringBuilder();
for (int i = 0; i < b.length; i++) {
String hex = Integer.toHexString(b[i] & 0xFF);
if (hex.length() == 1) {
builder.append('0'+hex);
hex = '0' + hex;
}
// System.out.print(hex.toUpperCase());
System.out.print(hex.toUpperCase());
builder.append(hex);
}
System.out.println();
return builder.toString();
}
public BigInteger random(BigInteger max) {
BigInteger r = new BigInteger(256, random);
// int count = 1;
while (r.compareTo(max) >= 0) {
r = new BigInteger(128, random);
// count++;
}
// System.out.println("count: " + count);
return r;
}
private boolean allZero(byte[] buffer) {
for (int i = 0; i < buffer.length; i++) {
if (buffer[i] != 0)
return false;
}
return true;
}
/**
* 加密
* @param input 待加密消息M
* @param publicKey 公钥
* @return byte[] 加密后的字节数组
*/
public byte[] encrypt(String input, ECPoint publicKey) {
System.out.println("publicKey is: "+publicKey);
byte[] inputBuffer = input.getBytes();
printHexString(inputBuffer);
/* 1 产生随机数k，k属于[1, n-1] */
BigInteger k = random(n);
System.out.print("k: ");
printHexString(k.toByteArray());
/* 2 计算椭圆曲线点C1 = [k]G = (x1, y1) */
ECPoint C1 = G.multiply(k);
byte[] C1Buffer = C1.getEncoded(false);
System.out.print("C1: ");
printHexString(C1Buffer);
// 3 计算椭圆曲线点 S = [h]Pb * curve没有指定余因子，h为空
// BigInteger h = curve.getCofactor(); System.out.print("h: ");
// printHexString(h.toByteArray()); if (publicKey != null) { ECPoint
// result = publicKey.multiply(h); if (!result.isInfinity()) {
// System.out.println("pass"); } else {
// System.err.println("计算椭圆曲线点 S = [h]Pb失败"); return null; } }
/* 4 计算 [k]PB = (x2, y2) */
ECPoint kpb = publicKey.multiply(k).normalize();
/* 5 计算 t = KDF(x2||y2, klen) */
byte[] kpbBytes = kpb.getEncoded(false);
DerivationFunction kdf = new KDF1BytesGenerator(new ShortenedDigest(
new SHA256Digest(), 20));
byte[] t = new byte[inputBuffer.length];
kdf.init(new ISO18033KDFParameters(kpbBytes));
kdf.generateBytes(t, 0, t.length);
if (allZero(t)) {
System.err.println("all zero");
}
/* 6 计算C2=M^t */
byte[] C2 = new byte[inputBuffer.length];
for (int i = 0; i < inputBuffer.length; i++) {
C2[i] = (byte) (inputBuffer[i] ^ t[i]);
}
/* 7 计算C3 = Hash(x2 || M || y2) */
byte[] C3 = calculateHash(kpb.getXCoord().toBigInteger(), inputBuffer,
kpb.getYCoord().toBigInteger());
/* 8 输出密文 C=C1 || C2 || C3 */
byte[] encryptResult = new byte[C1Buffer.length + C2.length + C3.length];
System.arraycopy(C1Buffer, 0, encryptResult, 0, C1Buffer.length);
System.arraycopy(C2, 0, encryptResult, C1Buffer.length, C2.length);
System.arraycopy(C3, 0, encryptResult, C1Buffer.length + C2.length,
C3.length);
System.out.print("密文: ");
printHexString(encryptResult);
return encryptResult;
}
public void decrypt(byte[] encryptData, BigInteger privateKey) {
System.out.println("privateKey is: "+privateKey);
System.out.println("encryptData length: " + encryptData.length);
byte[] C1Byte = new byte[65];
System.arraycopy(encryptData, 0, C1Byte, 0, C1Byte.length);
ECPoint C1 = curve.decodePoint(C1Byte).normalize();
/* 计算[dB]C1 = (x2, y2) */
ECPoint dBC1 = C1.multiply(privateKey).normalize();
/* 计算t = KDF(x2 || y2, klen) */
byte[] dBC1Bytes = dBC1.getEncoded(false);
DerivationFunction kdf = new KDF1BytesGenerator(new ShortenedDigest(
new SHA256Digest(), 20));
int klen = encryptData.length - 65 - 20;
System.out.println("klen = " + klen);
byte[] t = new byte[klen];
kdf.init(new ISO18033KDFParameters(dBC1Bytes));
kdf.generateBytes(t, 0, t.length);
if (allZero(t)) {
System.err.println("all zero");
}
/* 5 计算M'=C2^t */
byte[] M = new byte[klen];
for (int i = 0; i < M.length; i++) {
M[i] = (byte) (encryptData[C1Byte.length + i] ^ t[i]);
}
/* 6 计算 u = Hash(x2 || M' || y2) 判断 u == C3是否成立 */
byte[] C3 = new byte[20];
System.arraycopy(encryptData, encryptData.length - 20, C3, 0, 20);
byte[] u = calculateHash(dBC1.getXCoord().toBigInteger(), M, dBC1
.getYCoord().toBigInteger());
if (Arrays.equals(u, C3)) {
System.out.println("解密成功");
System.out.println("M' = " + new String(M));
} else {
System.out.print("u = ");
printHexString(u);
System.out.print("C3 = ");
printHexString(C3);
System.err.println("解密验证失败");
}
}
private byte[] calculateHash(BigInteger x2, byte[] M, BigInteger y2) {
ShortenedDigest digest = new ShortenedDigest(new SHA256Digest(), 20);
byte[] buf = x2.toByteArray();
digest.update(buf, 0, buf.length);
digest.update(M, 0, M.length);
buf = y2.toByteArray();
digest.update(buf, 0, buf.length);
buf = new byte[20];
digest.doFinal(buf, 0);
return buf;
}
private boolean between(BigInteger param, BigInteger min, BigInteger max) {
if (param.compareTo(min) >= 0 && param.compareTo(max) < 0) {
return true;
} else {
return false;
}
}
/**
* 公钥校验
* @param publicKey 公钥
* @return boolean true或false
*/
private boolean checkPublicKey(ECPoint publicKey) {
if (!publicKey.isInfinity()) {
BigInteger x = publicKey.getXCoord().toBigInteger();
BigInteger y = publicKey.getYCoord().toBigInteger();
if (between(x, new BigInteger("0"), p) && between(y, new BigInteger("0"), p)) {
BigInteger xResult = x.pow(3).add(a.multiply(x)).add(b).mod(p);
System.out.println("xResult: " + xResult.toString());
BigInteger yResult = y.pow(2).mod(p);
System.out.println("yResult: " + yResult.toString());
if (yResult.equals(xResult) && publicKey.multiply(n).isInfinity()) {
return true;
}
}
return false;
} else {
return false;
}
}
/**
* 获得公私钥对
* @return
*/
public SM2KeyPair generateKeyPair() {
BigInteger d = random(n.subtract(new BigInteger("1")));
SM2KeyPair keyPair = new SM2KeyPair(G.multiply(d).normalize(), d);
if (checkPublicKey(keyPair.getPublicKey())) {
System.out.println("generate key successfully");
return keyPair;
} else {
System.err.println("generate key failed");
return null;
}
}
public SM2Util() {
curve = new ECCurve.Fp(p, // q
a, // a
b); // b
G = curve.createPoint(xg, yg);
}
}
import java.math.BigInteger;
import org.bouncycastle.math.ec.ECPoint;
/**
* <B>说 明<B/>:SM2公私钥实体类
*/
public class SM2KeyPair {
/** 公钥 */
private ECPoint publicKey;
/** 私钥 */
private BigInteger privateKey;
SM2KeyPair(ECPoint publicKey, BigInteger privateKey) {
this.publicKey = publicKey;
this.privateKey = privateKey;
}
public ECPoint getPublicKey() {
return publicKey;
}
public BigInteger getPrivateKey() {
return privateKey;
}
}
import java.util.Arrays;
/**
* <B>说 明<B/>:SM2非对称加解密工具类测试
*/
public class SM2UtilTest {
/** 元消息串 */
private static String M = "哈哈哈，&*&…………&、、//\\!@#$%^&*()物品woyebuzhidaowozijiqiaodesha!@#$%^&*())))))ooooooooppppppppppppppppppplllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkffffffffffffffffffffffffffffffffffffff";
public static void main(String[] args) {
SM2Util sm2 = new SM2Util();
SM2KeyPair keyPair = sm2.generateKeyPair();
byte[] data = sm2.encrypt(M,keyPair.getPublicKey());
System.out.println("data is:"+Arrays.toString(data));
sm2.decrypt(data, keyPair.getPrivateKey());//71017045908707391874054405929626258767106914144911649587813342322113806533034
}
}
