麻烦写一段RSA加密PKCS1 JAVA代码

好的，以下是一个使用RSA加密PKCS1的JAVA代码示例，其中使用了Bouncy Castle库：

import org.bouncycastle.crypto.AsymmetricBlockCipher;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.engines.RSAEngine;
import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
import org.bouncycastle.crypto.params.RSAKeyParameters;
import org.bouncycastle.crypto.util.PublicKeyFactory;
import org.bouncycastle.crypto.util.PrivateKeyFactory;
import org.bouncycastle.crypto.util.PKCS1Encoding;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import java.security.Security;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.interfaces.RSAPublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;

public class RSAPKCS1Example {

    public static void main(String[] args) throws Exception {
        Security.addProvider(new BouncyCastleProvider());

        // 生成RSA密钥对
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA", "BC");
        keyPairGenerator.initialize(2048, new SecureRandom());
        KeyPair keyPair = keyPairGenerator.generateKeyPair();

        // 获取公钥和私钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

        // 加密数据
        byte[] data = "Hello, World!".getBytes("UTF-8");
        byte[] encryptedData = encrypt(data, publicKey);

        // 解密数据
        byte[] decryptedData = decrypt(encryptedData, privateKey);
        String decryptedText = new String(decryptedData, "UTF-8");

        // 输出结果
        System.out.println("原始数据：" + new String(data, "UTF-8"));
        System.out.println("加密后数据：" + bytesToHex(encryptedData));
        System.out.println("解密后数据：" + decryptedText);
    }

    public static byte[] encrypt(byte[] data, RSAPublicKey publicKey) throws Exception {
        AsymmetricKeyParameter keyParameters = PublicKeyFactory.createKey(publicKey.getEncoded());
        AsymmetricBlockCipher cipher = new PKCS1Encoding(new RSAEngine());
        cipher.init(true, keyParameters);
        return cipher.processBlock(data, 0, data.length);
    }

    public static byte[] decrypt(byte[] encryptedData, RSAPrivateKey privateKey) throws Exception {
        AsymmetricKeyParameter keyParameters = PrivateKeyFactory.createKey(privateKey.getEncoded());
        AsymmetricBlockCipher cipher = new PKCS1Encoding(new RSAEngine());
        cipher.init(false, keyParameters);
        return cipher.processBlock(encryptedData, 0, encryptedData.length);
    }

    public static String bytesToHex(byte[] data) {
        StringBuilder builder = new StringBuilder();
        for (byte b : data) {
            builder.append(String.format("%02X", b));
        }
        return builder.toString();
    }

}

在上面的示例中，我们使用了Bouncy Castle库来进行RSA加密和解密，并使用了PKCS1编码方式。首先，我们使用`KeyPairGenerator`生成一个2048位的RSA密钥对，并从中获取公钥和私钥。然后，我们将原始数据进行加密，并将加密后的数据存储在`encryptedData`数组中。最后，我们使用私钥对加密后的数据进行解密，并将解密后的数据存储在`decryptedData`数组中。注意，我们使用了一个辅助函数`bytesToHex`将字节数组转换为十六进制字符串，以便于输出结果。