使用BouncyCastle在Java中使用ECIES进行加密

Question

我正在尝试使用Java中的BouncyCastle使用ECC算法对某些内容进行加密。但是我对BouncyCastle库的说法例外：无法转换JCEECPublicKey为IESKey。我理解的是，所产生的公共密钥KeyPairGenerator是JCEECPublicKey不能在java的使用Cipher.init方法。有人可以告诉我如何将其转换为公钥或X509规范，以便可以将其用于加密。

这是我尝试过的代码

// add instance of provider class
Security.addProvider(new BouncyCastleProvider());

// initializing parameter specs secp256r1/prime192v1
ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("prime192v1");

// key pair generator to generate public and private key
KeyPairGenerator generator = KeyPairGenerator.getInstance("ECDH", new BouncyCastleProvider());

// initialize key pair generator
generator.initialize(ecSpec);

// Key pair to store public and private key
KeyPair keyPair = generator.generateKeyPair();

Cipher iesCipher = Cipher.getInstance("ECIES", new BouncyCastleProvider());
iesCipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic());

我也尝试将公钥转换为X509EncodedSpec，但出现相同的异常

X509EncodedKeySpec spec = new X509EncodedKeySpec(keyPair.getPublic().getEncoded());
KeyFactory factory = KeyFactory.getInstance("ECDH");

PublicKey publicKey = factory.generatePublic(spec);

我得到的例外是

java.lang.ClassCastException: org.bouncycastle.jce.provider.JCEECPublicKey cannot be cast to org.bouncycastle.jce.interfaces.IESKey
    at org.bouncycastle.jce.provider.JCEIESCipher.engineGetKeySize(JCEIESCipher.java:49)
    at javax.crypto.Cipher.passCryptoPermCheck(Cipher.java:1057)
    at javax.crypto.Cipher.checkCryptoPerm(Cipher.java:1015)
    at javax.crypto.Cipher.init(Cipher.java:1229)
    at javax.crypto.Cipher.init(Cipher.java:1173)
    at com.test.EciesTest.main(EciesTest.java:45)

编辑

基于注释，我正在使用的JDK版本是JDK 7-我正在使用的Oracle Import语句：

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Security;
import java.security.spec.ECGenParameterSpec;
import javax.crypto.Cipher;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

Answer 1

请尝试以下操作：

// add instance of provider class
Security.addProvider(new BouncyCastleProvider());

String name = "secp256r1";

// NOTE just "EC" also seems to work here
KeyPairGenerator kpg = KeyPairGenerator.getInstance("ECDH", BouncyCastleProvider.PROVIDER_NAME);
kpg.initialize(new ECGenParameterSpec(name));

// Key pair to store public and private key
KeyPair keyPair = kpg.generateKeyPair();

Cipher iesCipher = Cipher.getInstance("ECIES", BouncyCastleProvider.PROVIDER_NAME);
iesCipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic());

请注意，通常，在尝试通过JCE使用Bouncy时，最好保留JCE类而不是Bouncy Castle类。在这种情况下，问题可能出在提供给密钥生成器的参数上。

在上面的代码中，我使用了，BouncyCastleProvider.PROVIDER_NAME但是"BC"当然可以很好地工作。尽管应该不影响最终结果，但每次都重新初始化提供者不是一个好主意。

确保您具有最新的系统来运行此代码。该代码已在以下系统上经过测试：

 --- runtime information --- 
Properties:
    java.vendor                : Oracle Corporation
    java.specification.name    : Java Platform API Specification
    java.specification.version : 1.8
    java.runtime.name          : Java(TM) SE Runtime Environment
    java.runtime.version       : 1.8.0_65-b17
    java.vm.name               : Java HotSpot(TM) 64-Bit Server VM
Unlimited crypto: yes
 --- info for provider Bouncy Castle --- 
Bouncy Castle version: 1.520000
Bouncy Castle provider registered: yes