sm2 加 解 密 工 具

package com.kasensoft.sm2; 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; import org.bouncycastle.util.encoders.Base64; 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; /** * 将字节数组转成base64字符串 * @param b * @return */ private static String toBase64Str(byte[] b) { return new String(Base64.encode(b)); } /** * base64字符串转成字节数组 * * @param encryptMsg * base64字符串 * @return 转换后的字节数组 **/ private static byte[] toByteArray(String encryptMsg) { return Base64.decode(encryptMsg.getBytes()); } 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 String encrypt(String input, ECPoint publicKey) { System.out.println("publicKey is: "+publicKey); System.out.println("-------------------"); byte[] inputBuffer = input.getBytes(); toBase64Str(inputBuffer); /* 1 产生随机数k，k属于[1, n-1] */ BigInteger k = random(n); /* 2 计算椭圆曲线点C1 = [k]G = (x1, y1) */ ECPoint C1 = G.multiply(k); byte[] C1Buffer = C1.getEncoded(false); // 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: "); // toBase64Str(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); return toBase64Str(encryptResult); } /** * 解密 * @param encryptMsg 加密消息 * @param privateKey 私钥 * @return */ public String decrypt(String encryptMsg, BigInteger privateKey) { return this.decrypt(toByteArray(encryptMsg), privateKey); } public String 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"); String dMsg = new String(M); System.out.println("M' = " + dMsg); return dMsg; } else { System.out.print("u = "); toBase64Str(u); System.out.print("C3 = "); toBase64Str(C3); System.err.println("解密验证失败"); return null; } } 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: