简介

项目用到了加密相关知识，主要包括加解密和签名过程。文章用java简单实现这一过程的工具类。（不包括公私钥的生成）

加密、签名流程图

具体代码实现

package encrypt;

import org.apache.xmlbeans.impl.util.HexBin;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

/**
 * @author txb
 * @date 2020年03月30日
 */
public class RSATest {

    private static final String CHARSET="utf-8";
    private static final String ALGORITHMS="RSA";
    private static final String SIGNALGORITHMS="SHA256withRSA";


    static String myRSAPublicKey="MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC9j9jvyIoanJebGJb+Zns2TaHl" +
            "xUiV9DrPCRXGHwKwy+Na8Au0zdu4rg6Qcly632HXDGlNApZYm1YFr7olGgIWCslp" +
            "v6C2kDwkIENZC41rBebT4V21E9Fd6EAdOg+sWmv9hj5HZlcfLUyLqJffv7NF9Z7H" +
            "zCbscDuUtTAjjENO8wIDAQAB";
    static String myRSAPrivateKey="MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAL2P2O/Iihqcl5sY" +
            "lv5mezZNoeXFSJX0Os8JFcYfArDL41rwC7TN27iuDpByXLrfYdcMaU0CllibVgWv" +
            "uiUaAhYKyWm/oLaQPCQgQ1kLjWsF5tPhXbUT0V3oQB06D6xaa/2GPkdmVx8tTIuo" +
            "l9+/s0X1nsfMJuxwO5S1MCOMQ07zAgMBAAECgYAxahonB6PYpBFxQMu7rYNY+IvH" +
            "ldICJRRffALNDrBo3f16azDiBPfOALGTPfymSiz7HiUlChOfLX8TJGfl3A3Gtisw" +
            "YnLPYw/+uZXLLfwSA+sJjOZqxozTrr90o5Lni2XQx8u1oj1XnPTxZrHlGnuiXpUL" +
            "IHugjb1xR6cs70heoQJBAOivnfe2JHTnDT5wYgZ9q/7hKRuqINnhcJ/eNnIN8HPp" +
            "daRTYf7VjNcBzHRFSmDQVmciQ1PHJtN/G0nK4vSUoEUCQQDQjhl/V5KO535u6br2" +
            "zqb99J9TKIZtAuTly6Su1tSuREBZ2TFRZ2kQg7ayzgBL3+0Q3N+8EGWhFPWJembq" +
            "rbHXAkEAo8Z4OVJKdr3p5HjVhhwOY2e3t3EXjkPPMbcGO2D0TaGU3ASUhPlqGCt7" +
            "7JqYr2v0ZMMJAH68JUDhxB65f8zcwQJBAJA51PQ1kYr2GH+Hb96CpwV1CEGwAtac" +
            "a8NnA2pN8yLY3E/GXc7X3tam38/jmlzebMl+ldMu27l8DxmV5lpg6F0CQEofIGtb" +
            "TxasTdNIDUvHcVOn1N5fPN/bNy8oeLaL2a8Y1UA8CIYMthkcigGhqkXtNAKCUR0k" +
            "9E4nufNoYHANU1M=";



    public static PublicKey getPublicKey(String publicKey){
        try {
            X509EncodedKeySpec spec=new X509EncodedKeySpec(Base64.getDecoder().decode(publicKey));
            KeyFactory keyFactory=KeyFactory.getInstance(ALGORITHMS);
            return keyFactory.generatePublic(spec);

        } catch (NoSuchAlgorithmException e) {
             e.printStackTrace();
        }catch (InvalidKeySpecException e) {
            e.printStackTrace();
        }

        return null;
    }

    public static PrivateKey getPrivateKey(String privateKey){
        try {
            PKCS8EncodedKeySpec spec=new PKCS8EncodedKeySpec(Base64.getDecoder().decode(privateKey));
            KeyFactory keyFactory=KeyFactory.getInstance(ALGORITHMS);
            return keyFactory.generatePrivate(spec);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        }
        return null;
    }

    //公钥加密
    public static String encrypt(String plainText,String publicKeyStr){
        try {
            Cipher cipher = Cipher.getInstance(ALGORITHMS);//根据需要选择分组模式、填充。比如：RSA/ECB/NoPadding
            PublicKey publickKey=getPublicKey(publicKeyStr);
            if(publickKey!=null){
                cipher.init(Cipher.ENCRYPT_MODE,publickKey);
                byte[] bytes=cipher.doFinal(plainText.getBytes(CHARSET));
                return Base64.getEncoder().encodeToString(bytes);//base64编码
            }
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }catch (UnsupportedEncodingException e){
            e.printStackTrace();
        }
        return null;
    }

    //私钥解密
    public static String decrypt(String encryptText,String privateKeyStr){
        try {
            Cipher cipher = Cipher.getInstance(ALGORITHMS);//根据需要选择分组模式、填充。比如：RSA/ECB/NoPadding
            PrivateKey privateKey=getPrivateKey(privateKeyStr);
            if(privateKey!=null){
                cipher.init(Cipher.DECRYPT_MODE,privateKey);
                byte[] bytes=cipher.doFinal(Base64.getDecoder().decode(encryptText));//encryptText之前用base64编码过，要解码成bytes
                return new String(bytes);//得到明文
            }
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * 签名
     * 发送方私钥签名
     */
    public static String sign(String encryptText,String privateKeyStr){
        try {
            Signature signature=Signature.getInstance(SIGNALGORITHMS);
            PrivateKey privateKey=getPrivateKey(privateKeyStr);
            if(privateKey!=null){
                signature.initSign(privateKey);
                signature.update(encryptText.getBytes(CHARSET));
                byte[] bytes=signature.sign();
                return HexBin.bytesToString(bytes);//转成hex字符串
            }
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (SignatureException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * 验签
     * 发送方公钥验签
     */
    public static boolean verifySign(String signText,String encryptText,String publicKeyStr){
        PublicKey publickKey=getPublicKey(publicKeyStr);
        try {
            if(publickKey!=null){
                Signature signature=Signature.getInstance(SIGNALGORITHMS);
                signature.initVerify(publickKey);
                signature.update(encryptText.getBytes(CHARSET));
                return signature.verify(HexBin.stringToBytes(signText));//hex字符串转bytes
            }
        } catch (UnsupportedEncodingException e){
            e.printStackTrace();
        }catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (SignatureException e) {
            e.printStackTrace();
        }
        return false;
    }


    //为了方便，只用一对公私钥，实际需要发送方、接收方两对公私钥
    public static void main(String[] args) {
        String plainText="我是明文 1 3 5 7 9";
        System.out.println("明文:"+plainText);
        String encryptText=encrypt(plainText,myRSAPublicKey);
        System.out.println("密文"+encryptText);

        String signText=sign(encryptText,myRSAPrivateKey);
        System.out.println("信息摘要："+signText);
        if(verifySign(signText,encryptText,myRSAPublicKey)){
            System.out.println("验签通过");
            String decodeText=decrypt(encryptText,myRSAPrivateKey);
            System.out.println("解密后："+decodeText);
        }
    }

}