使用 Bouncy Castle 生成 ECPublicKey
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这会生成在 JCE/JCA 中使用的 EC 公钥。 Bouncy Castle 提供商可以直接使用这些软件密钥。否则 Bouncy 仅用于生成生成公钥所需的参数。
package nl.owlstead.stackoverflow;
import static java.nio.charset.StandardCharsets.US_ASCII;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.KeyPairGenerator;
import java.security.Security;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECGenParameterSpec;
import java.security.spec.ECParameterSpec;
import java.security.spec.ECPoint;
import java.security.spec.ECPublicKeySpec;
import javax.crypto.Cipher;
import org.bouncycastle.jce.ECNamedCurveTable;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
import org.bouncycastle.jce.spec.ECNamedCurveSpec;
import org.bouncycastle.util.encoders.Hex;
public class ECPublicKeyFactory {
public static void main(String[] args) throws Exception {
String name = "secp256r1";
Security.addProvider(new BouncyCastleProvider());
// === NOT PART OF THE CODE, JUST GETTING TEST VECTOR ===
KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC", "BC");
ECGenParameterSpec ecGenParameterSpec = new ECGenParameterSpec(name);
kpg.initialize(ecGenParameterSpec);
ECPublicKey key = (ECPublicKey) kpg.generateKeyPair().getPublic();
byte[] x = key.getW().getAffineX().toByteArray();
byte[] y = key.getW().getAffineY().toByteArray();
// === here the magic happens ===
KeyFactory eckf = KeyFactory.getInstance("EC");
ECPoint point = new ECPoint(new BigInteger(1, x), new BigInteger(1, y));
ECNamedCurveParameterSpec parameterSpec = ECNamedCurveTable.getParameterSpec(name);
ECParameterSpec spec = new ECNamedCurveSpec(name, parameterSpec.getCurve(), parameterSpec.getG(), parameterSpec.getN(), parameterSpec.getH(), parameterSpec.getSeed());
ECPublicKey ecPublicKey = (ECPublicKey) eckf.generatePublic(new ECPublicKeySpec(point, spec));
System.out.println(ecPublicKey.getClass().getName());
// === test 123 ===
Cipher ecies = Cipher.getInstance("ECIESwithAES", "BC");
ecies.init(Cipher.ENCRYPT_MODE, ecPublicKey);
byte[] ct = ecies.doFinal("owlstead".getBytes(US_ASCII));
System.out.println(Hex.toHexString(ct));
}
}
生成充气城堡 ECPublicKeyParameters
最初我认为需要 Bouncy Castle 特定密钥，因此以下代码生成了用于 Bouncy Castle 轻量级 API 的 EC 公钥。
package nl.owlstead.stackoverflow;
import java.math.BigInteger;
import java.security.KeyPairGenerator;
import java.security.Security;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECGenParameterSpec;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.x9.ECNamedCurveTable;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.crypto.params.ECNamedDomainParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.math.ec.ECPoint;
import org.bouncycastle.util.encoders.Hex;
public class BC_EC_KeyCreator {
public static void main(String[] args) throws Exception {
String name = "secp256r1";
// === NOT PART OF THE CODE, JUST GETTING TEST VECTOR ===
Security.addProvider(new BouncyCastleProvider());
KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC", "BC");
kpg.initialize(new ECGenParameterSpec(name));
ECPublicKey key = (ECPublicKey) kpg.generateKeyPair().getPublic();
byte[] x = key.getW().getAffineX().toByteArray();
byte[] y = key.getW().getAffineY().toByteArray();
// assumes that x and y are (unsigned) big endian encoded
BigInteger xbi = new BigInteger(1, x);
BigInteger ybi = new BigInteger(1, y);
X9ECParameters x9 = ECNamedCurveTable.getByName(name);
ASN1ObjectIdentifier oid = ECNamedCurveTable.getOID(name);
ECCurve curve = x9.getCurve();
ECPoint point = curve.createPoint(xbi, ybi);
ECNamedDomainParameters dParams = new ECNamedDomainParameters(oid,
x9.getCurve(), x9.getG(), x9.getN(), x9.getH(), x9.getSeed());
ECPublicKeyParameters pubKey = new ECPublicKeyParameters(point, dParams);
System.out.println(pubKey);
// some additional encoding tricks
byte[] compressed = point.getEncoded(true);
System.out.println(Hex.toHexString(compressed));
byte[] uncompressed = point.getEncoded(false);
System.out.println(Hex.toHexString(uncompressed));
}
}
这很棘手，因为我不想包含任何 JCE 特定代码，而且X9ECParameters 不是ECDomainParameters 的子类。所以我使用了从 Bouncy Castle 代码库中其他地方复制的 ECNamedDomainParameters 的转换。