package digest;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

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

public class DigestExample {

    public static void main(String[] args) throws Exception {
        //加密內容
        final String content = "hello hello hello"
 
;
        /*
         * 單向加密 md5 & sha
         */
        //md5 加密
        MessageDigest md5 = MessageDigest.getInstance("md5");
        byte[] md5SecretStr = md5.digest(content.getBytes());
        System.out.print("md5 加密 : { " + new String(Base64.encodeBase64(md5SecretStr)) + " }\n\r");

        //sha 加密
        MessageDigest sha = MessageDigest.getInstance
 
("sha");
        byte[] shaSecretBytes = sha.digest(content.getBytes());
        System.out.print("sha 加密 : { " + new String(Base64.encodeBase64(shaSecretBytes)) + " }\n\r");

        /*
         * 對稱加密 aes & des
         */
        //aes 加密
        KeyGenerator aesKeyGenerator = KeyGenerator.getInstance
 
("aes");
        SecretKey aesSecretKey = aesKeyGenerator.generateKey();
        Cipher aesCipher = Cipher.getInstance("aes");
        aesCipher.init(Cipher.ENCRYPT_MODE, aesSecretKey);
        byte[] aseResultBytes = aesCipher.doFinal(content.getBytes());
        System.out.print("aes 加密 : { " + new String(Base64.encodeBase64(aseResultBytes)) + " }\n\r");

        //aes 解密
        aesCipher.init(Cipher.DECRYPT_MODE, aesSecretKey);
        aseResultBytes = aesCipher.doFinal(aseResultBytes);
        System.out.print("aes 解密: { " + new String(aseResultBytes) + " }\n\r");


        //des 加密
        KeyGenerator desKeyGenerator = KeyGenerator.getInstance("aes");
        SecretKey desSecretKey = desKeyGenerator.generateKey();
        Cipher desCipher = Cipher.getInstance("aes");
        desCipher.init(Cipher.ENCRYPT_MODE, desSecretKey);
        byte[] dseResultBytes = desCipher.doFinal(content.getBytes());
        System.out.print("des 加密 : { " + new String(Base64.encodeBase64(dseResultBytes)) + " }\n\r");

        desCipher.init(Cipher.DECRYPT_MODE, desSecretKey);
        dseResultBytes = desCipher.doFinal(dseResultBytes);
        System.out.print("aes 解密: { " + new String(dseResultBytes) + " }\n\r");

    }

}

console run result

md5 : { ZnptFLLcFU/qw2LdrU1MqA== }

sha : { g52cyhSXeHXr8kcWODkq738OAVk= }

aes 加密 : { pudmyrvBANStqfcDIb7+DFPK+5gPZP/ais6sibTKyIk= }

aes 解密: { hello hello hello }

des : { Nx2RwaJBl5+P2eVb0v+JRVTd8tfwAQQ7KA28n97Ln8E= }

aes 解密: { hello hello hello }

rsa 非對稱加密

package digest;

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;

import javax.crypto.Cipher;

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


public class RsaExample {
    public static void main(String[] args) throws Exception {
        final String context = "rsa加密";


        KeyPairGenerator kpg = KeyPairGenerator.getInstance("rsa");
        KeyPair gkp = kpg.generateKeyPair();

        PrivateKey privateKey = gkp.getPrivate();
        PublicKey publicKey = gkp.getPublic();
        byte[] encode1 = privateKey.getEncoded();
        byte[] encode2 = publicKey.getEncoded();

        byte[] key1 = Base64.encodeBase64(encode1);
        byte[] key2 = Base64.encodeBase64(encode2);
        System.out.println(new String(key1));
        System.out.println(new String(key2));
        /*System.out.println("privateKey:{"+privateKey+"}");
        System.out.println("publicKey:{" +publicKey+"}");*/


        Cipher cipher = Cipher.getInstance("rsa");
        cipher.init(1, privateKey);
        byte[] result = cipher.doFinal(context.getBytes());

        byte[] signatrue = Base64.encodeBase64(result);

        System.out.println("result:{" + new String(signatrue)+"}");

        byte[] i = Base64.decodeBase64(signatrue);
        cipher.init(2, publicKey);
        System.out.println(new String(cipher.doFinal(i)));

    }
}

console run result

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
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCPirX/2wD50xEeMC/o2MEoI78IN1VOCka3b6DoqcvOtkTnCXcPZwhkSMnxaSGBWAC2OZJtBk20dXL3weTeOxmxGnfDjLDItSTrzYIpKfKH1IBXeGq7Ig+qerFne0bML1X4HRSkJj+jm7vYzOcwmcXrWh/29MSurQTSSVv8J/sxvQIDAQAB
privateKey:{Sun RSA private CRT key, 1024 bits
  modulus:          100798507655562672634382563625239291964945102222464707977557265818850161373345900576705678605564617099559134111187263533690577667029773051561093784895113396514352229224857085774815551784918475310931537765905461572526427050491602207190137661866307492752828388294013838106222346293330945028978188314252819509693
  public exponent:  65537
  private exponent: 20818905345464338263561078188370524376115734679391523676460856464652879813687079210313076057874523659301347930619814748798932805909867830781557982091646774464612734768033397966651666313646610127404321982687308504412645000261745579169493965806942893895422786998315749053429010938321263854313553436041981325313
  prime p:          12235258251843427800322533580271468214768411862644285725616323425147295210732054481178485319627614069545483443675930314214646122186102225213965689240712673
  prime q:          8238363717445509899921811355733496220359326926172197592231787257563498251698094349890806400362388734966369330560689902140965710482536375658188849975803741
  prime exponent p: 943169884009231384519118050071432281322154153075040534138176388053223910228090074902935865766799003301093769282249720728937733025377854368996973649145985
  prime exponent q: 77937432363645210155355341876417407824935268538791255431034501116764101439687787004780505183708149834126508460070307449645219349362536474176069807665873
  crt coefficient:  11228541263870362801929539584646038800421516291723873773379889902535223043030350582050117672514417336396982286570742313855229425370741626261320117750796856}
publicKey:{Sun RSA public key, 1024 bits
  modulus: 100798507655562672634382563625239291964945102222464707977557265818850161373345900576705678605564617099559134111187263533690577667029773051561093784895113396514352229224857085774815551784918475310931537765905461572526427050491602207190137661866307492752828388294013838106222346293330945028978188314252819509693
  public exponent: 65537}
result:{XxdVrhgArX5/AnDGGqU2/VGTcrmjcY37SnKxnTR7+5VFaACbj6aSi+S3xyfgu1UHwlDUrpYczCU+ikXrbSQWs9+WGT1CixYrCC04VuxxZ32G4gKLY8Q9Ag904PuTQbA/s/YWuHxfvKykr9r2Epx2wHrZiRKA6eFvVQIQCKzWjvk=}
rsa加密