Java RSA算法怎么实现

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Java 中可以使用 Java 内置的加密库 javax.crypto 来实现 RSA 算法。

下面是一个简单的 RSA 加密和解密的示例代码：

import javax.crypto.Cipher;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

public class RSAExample {public static void main(String[] args) throws Exception {String originalText = "Hello, RSA!";

        // 生成公私密钥对 
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        keyPairGenerator.initialize(2048);
        KeyPair keyPair = keyPairGenerator.generateKeyPair();

        PublicKey publicKey = keyPair.getPublic();
        PrivateKey privateKey = keyPair.getPrivate();

        // 使用公钥加密数据 
        byte[] encryptedBytes = encrypt(originalText, publicKey);

        // 使用私钥解密数据 
        String decryptedText = decrypt(encryptedBytes, privateKey);

        System.out.println("Original Text: " + originalText);
        System.out.println("Encrypted Text: " + Base64.getEncoder().encodeToString(encryptedBytes));
        System.out.println("Decrypted Text: " + decryptedText);
    }

    public static byte[] encrypt(String text, PublicKey publicKey) throws Exception {Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        return cipher.doFinal(text.getBytes());
    }

    public static String decrypt(byte[] encryptedBytes, PrivateKey privateKey) throws Exception {Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] decryptedBytes = cipher.doFinal(encryptedBytes);
        return new String(decryptedBytes);
    }
}