RSA加解密工具类

参考: https://github.com/sjyuan-cc/cc.sjyuan.commons/blob/master/src/main/java/cc/sjyuan/commons/util/encryptor/RSAUtils.java

package com.tinfinite.common;

import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.security.spec.X509EncodedKeySpec;

public class RSAUtils {
    public static final String RSA_ECB_PKCS1_PADDING = "RSA/ECB/PKCS1Padding";

    public static final int KEY_SIZE_2048 = 2048;
    public static final int KEY_SIZE_1024 = 1024;

    private RSAUtils() {
    }

    private static final String ALGORITHM = "RSA";

    public static KeyPair generateKeyPair() {
        return generateKeyPair(KEY_SIZE_2048);
    }

    public static KeyPair generateKeyPair(int keySize) {
        try {
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(ALGORITHM);
            keyPairGenerator.initialize(keySize);
            return keyPairGenerator.generateKeyPair();
        } catch (NoSuchAlgorithmException e) {
            throw new IllegalArgumentException("Failed to generate key pair!", e);
        }
    }

    public static PublicKey getPublicKey(String base64PublicKey) {
        try {
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(Base64.decodeBase64(base64PublicKey));
            KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
            PublicKey publicKey = keyFactory.generatePublic(keySpec);
            return publicKey;
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to get public key!", e);
        }
    }

    public static PublicKey getPublicKey(BigInteger modulus, BigInteger exponent) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
            RSAPublicKeySpec keySpec = new RSAPublicKeySpec(modulus, exponent);
            return keyFactory.generatePublic(keySpec);
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to get public key!", e);
        }
    }

    public static String getBase64PublicKey(PublicKey publicKey) {
        return Base64.encodeBase64String(publicKey.getEncoded());
    }

    public static PrivateKey getPrivateKey(String base64PrivateKey) {
        try {
            PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(base64PrivateKey));
            KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
            PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
            return privateKey;
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to get private key!", e);
        }
    }

    public static PrivateKey getPrivateKey(BigInteger modulus, BigInteger exponent) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
            RSAPrivateKeySpec keySpec = new RSAPrivateKeySpec(modulus, exponent);
            return keyFactory.generatePrivate(keySpec);
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to get private key!", e);
        }
    }

    public static String getBase64PrivateKey(PrivateKey privateKey) {
        return Base64.encodeBase64String(privateKey.getEncoded());
    }

    public static byte[] encryptAsByteArray(String data, PublicKey publicKey) {
        try {
            Cipher cipher = Cipher.getInstance(RSA_ECB_PKCS1_PADDING);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            return cipher.doFinal(data.getBytes());
        } catch (Exception e) {
            throw new IllegalArgumentException("Encrypt failed!", e);
        }
    }

    public static byte[] encryptAsByteArray(String data, String base64PublicKey) {
        return encryptAsByteArray(data, getPublicKey(base64PublicKey));
    }

    public static String encryptAsString(String data, PublicKey publicKey) {
        return Base64.encodeBase64String(encryptAsByteArray(data, publicKey));
    }

    public static String encryptAsString(String data, String base64PublicKey) {
        return Base64.encodeBase64String(encryptAsByteArray(data, getPublicKey(base64PublicKey)));
    }

    public static String decrypt(byte[] data, PrivateKey privateKey) {
        try {
        	Cipher cipher = Cipher.getInstance(RSA_ECB_PKCS1_PADDING);
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            return new String(cipher.doFinal(data));
        } catch (Exception e) {
            throw new IllegalArgumentException("Decrypt failed!", e);
        }
    }

    public static String decrypt(byte[] data, String base64PrivateKey) {
        return decrypt(data, getPrivateKey(base64PrivateKey));
    }

    public static String decrypt(String data, PrivateKey privateKey) {
        return decrypt(Base64.decodeBase64(data), privateKey);
    }

    public static String decrypt(String base64PrivateKey, String data) {
        return decrypt(Base64.decodeBase64(data), base64PrivateKey);
    }
    
    public static void main(String[] args) throws UnsupportedEncodingException {
    	   KeyPair keyPair = generateKeyPair();
    	   String pubKey = Base64.encodeBase64String(keyPair.getPublic().getEncoded());
    	   String priKey = Base64.encodeBase64String(keyPair.getPrivate().getEncoded());
	   System.out.println("pubKey---------" + pubKey);
	   System.out.println("priKey---------" + priKey);
	}
    
}

使用main方法生成公私钥即可直接使用。

注意: 此公私钥是经过base64处理的，加解密也掺杂有base64的处理