rsa script groovy

rsa.groovy

package tools;

import org.apache.commons.io.IOUtils;
import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
* 分段加密，无数据大小限制
*/
public class XRsa {
    public static final String CHARSET = "UTF-8";
    public static final String RSA_ALGORITHM = "RSA";
    public static final String RSA_ALGORITHM_SIGN = "SHA256WithRSA";

    private RSAPublicKey publicKey;
    private RSAPrivateKey privateKey;

    public static final class Builder {
        private RSAPublicKey publicKey;
        private RSAPrivateKey privateKey;

        public Builder setPublicKey(String publicKeyStr) {
            try {
                KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
                //通过X509编码的Key指令获得公钥对象
                X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKeyStr));
                this.publicKey = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
            } catch (Exception e) {
                throw new RuntimeException("不支持的密钥", e);
            }

            return this;
        }

        public Builder setPrivateKey(String privateKeyStr) {
            try {
                KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
                PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKeyStr));
                this.privateKey = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
            } catch (Exception e) {
                throw new RuntimeException("不支持的密钥", e);
            }
            return this;
        }

        public XRsa build() {
            XRsa xRsa = new XRsa();
            xRsa.setPrivateKey(privateKey);
            xRsa.setPublicKey(publicKey);
            return xRsa;
        }
    }

    public static Builder createBuilder() {
        return new Builder();
    }


    public static Map<String, String> createKeys(int keySize){
        //为RSA算法创建一个KeyPairGenerator对象
        KeyPairGenerator kpg;
        try{
            kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM, "BC");
        }catch(Exception e){
            throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");
        }

        //初始化KeyPairGenerator对象,不要被initialize()源码表面上欺骗,其实这里声明的size是生效的
        kpg.initialize(keySize);
        //生成密匙对
        KeyPair keyPair = kpg.generateKeyPair();
        //得到公钥
        Key publicKey = keyPair.getPublic();
        String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());
        //得到私钥
        Key privateKey = keyPair.getPrivate();
        String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());
        Map<String, String> keyPairMap = new HashMap<String, String>();
        keyPairMap.put("publicKey", publicKeyStr);
        keyPairMap.put("privateKey", privateKeyStr);

        return keyPairMap;
    }

    public String publicEncrypt(String data){
        try{
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
        }catch(Exception e){
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    public String privateDecrypt(String data){
        try{
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
        }catch(Exception e){
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    public String privateEncrypt(String data){
        try{
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
        }catch(Exception e){
            throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
        }
    }

    public String publicDecrypt(String data){
        try{
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, publicKey);
            return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
        }catch(Exception e){
            throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
        }
    }

    public String sign(String data){
        try{
            //sign
            Signature signature = Signature.getInstance(RSA_ALGORITHM_SIGN);
            signature.initSign(privateKey);
            signature.update(data.getBytes(CHARSET));
            return Base64.encodeBase64URLSafeString(signature.sign());
        }catch(Exception e){
            throw new RuntimeException("签名字符串[" + data + "]时遇到异常", e);
        }
    }

    public boolean verify(String data, String sign){
        try{
            Signature signature = Signature.getInstance(RSA_ALGORITHM_SIGN);
            signature.initVerify(publicKey);
            signature.update(data.getBytes(CHARSET));
            return signature.verify(Base64.decodeBase64(sign));
        }catch(Exception e){
            throw new RuntimeException("验签字符串[" + data + "]时遇到异常", e);
        }
    }

    private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize){
        int maxBlock = 0;
        if(opmode == Cipher.DECRYPT_MODE){
            maxBlock = keySize / 8;
        }else{
            maxBlock = keySize / 8 - 11;
        }
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] buff;
        int i = 0;
        try{
            while(datas.length > offSet){

                if(datas.length - offSet > maxBlock){
                    buff = cipher.doFinal(datas, offSet, maxBlock);
                } else {
                    buff = cipher.doFinal(datas, offSet, datas.length - offSet);
                }
                out.write(buff, 0, buff.length);
                i++;
                offSet = i * maxBlock;
            }
        }catch(Exception e){
            throw new RuntimeException("加解密阀值为["+maxBlock+"]的数据时发生异常", e);
        }
        byte[] resultDatas = out.toByteArray();
        IOUtils.closeQuietly(out);
        return resultDatas;
    }

    public void setPublicKey(RSAPublicKey publicKey) {
        this.publicKey = publicKey;
    }

    public void setPrivateKey(RSAPrivateKey privateKey) {
        this.privateKey = privateKey;
    }
}