JAVA開発における4つの暗号化方法を簡単に理解できます

文書ディレクトリ
一、工具類

md 5暗号化ツールクラス

base 64暗号化ツールクラス

Bcryptツールクラス

二、暗号化テスト

MD 5暗号化テスト

base 64暗号化テスト

SHA暗号化テスト

BCrypt暗号化テスト

一、工具類
1.md 5暗号化ツールクラス

package   Tester.util;
import java.security.MessageDigest;

public class MD5Utils {

    private static final String hexDigIts[] = {"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};

    /**
     * MD5  
     * @param origin   
     * @param charsetname   
     * @return
     */
    public static String MD5Encode(String origin, String charsetname){
        String resultString = null;
        try{
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if(null == charsetname || "".equals(charsetname)){
                resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
            }else{
                resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
            }
        }catch (Exception e){
        }
        return resultString;
    }

    public static String byteArrayToHexString(byte b[]){
        StringBuffer resultSb = new StringBuffer();
        for(int i = 0; i < b.length; i++){
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    public static String byteToHexString(byte b){
        int n = b;
        if(n < 0){
            n += 256;
        }
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigIts[d1] + hexDigIts[d2];
    }

}

2.base 64暗号化ツールクラス

package   Tester.util;
import org.apache.commons.codec.binary.Base64;
import java.io.UnsupportedEncodingException;

public class Base64Util {

    //      
    private static final String UTF_8 = "UTF-8";

    /**
     *      
     * @param inputData
     * @return
     */
    public static String decodeData(String inputData) {
        try {
            if (null == inputData) {
                return null;
            }
            return new String(Base64.decodeBase64(inputData.getBytes(UTF_8)), UTF_8);
        } catch (UnsupportedEncodingException e) {
        }
        return null;
    }

    /**
     *          
     * @param inputData
     * @return
     */
    public static String encodeData(String inputData) {
        try {
            if (null == inputData) {
                return null;
            }
            return new String(Base64.encodeBase64(inputData.getBytes(UTF_8)), UTF_8);
        } catch (UnsupportedEncodingException e) {
        }
        return null;
    }

    public static void main(String[] args) {
        System.out.println(Base64Util.encodeData("    "));
        String enStr = Base64Util.encodeData("    ");
        System.out.println(Base64Util.decodeData(enStr));
    }
}

3.Bcryptツールクラス

package   Tester.util;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.lang3.StringUtils;
import org.mindrot.bcrypt.BCrypt;

public class BcryptCipher {
    // generate salt seed
    private static final int SALT_SEED = 12;
    // the head fo salt
    private static final String SALT_STARTSWITH = "$2a$12";

    public static final String SALT_KEY = "salt";

    public static final String CIPHER_KEY = "cipher";

    /**
     * Bcrypt encryption algorithm method
     * @param encryptSource 
     *                  need to encrypt the string
     * @return Map , two values in Map , salt and cipher
     */
    public static Map Bcrypt(final String encryptSource) {
        String salt  = BCrypt.gensalt(SALT_SEED);
        Map bcryptResult = Bcrypt(salt, encryptSource);
        return bcryptResult;
    }
    /**
     * 
     * @param salt encrypt salt, Must conform to the rules 
     * @param encryptSource
     * @return
     */
    public static Map Bcrypt(final String salt, final String encryptSource) {
        if (StringUtils.isBlank(encryptSource)) {
            throw new RuntimeException("Bcrypt encrypt input params can not be empty");
        }

        if (StringUtils.isBlank(salt) || salt.length() != 29) {
            throw new RuntimeException("Salt can't be empty and length must be to 29");
        }
        if (!salt.startsWith(SALT_STARTSWITH)) {
            throw new RuntimeException("Invalid salt version, salt version is $2a$12");
        }

        String cipher = BCrypt.hashpw(encryptSource, salt);
        Map bcryptResult = new HashMap();
        bcryptResult.put(SALT_KEY, salt);
        bcryptResult.put(CIPHER_KEY, cipher);
        return bcryptResult;
    }

}

二、暗号化テスト
1.MD 5暗号化テスト

package   Tester;

import   Tester.util.MD5Utils;

/**
 * MD5  
 */
public class MD5Test {
    public static void main(String[] args) {
        String string = "     ";
        String byteArrayToHexString = MD5Utils.byteArrayToHexString(string.getBytes());
        System.out.println(byteArrayToHexString);//e68891e698afe4b880e58fa5e8af9d

    }
}

2.base 64暗号化テスト

package   Tester;

import java.util.Base64;

import   Tester.util.Base64Util;

/**
 * base64  
 */
public class Bast64Tester {

    public static void main(String[] args) {
        String string = "       ";
        String encodeData = Base64Util.encodeData(string); //  
        String decodeData = Base64Util.decodeData(encodeData); //  
        System.out.println(encodeData);//5oiR5piv5LiA5Liq5a2X56ym5Liy
        System.out.println(decodeData);//       

    }

}

3.SHA暗号化テスト

package   Tester;

import org.apache.commons.codec.digest.Sha2Crypt;

/**
 * SHA  
 */
public class ShaTest {

    public static void main(String[] args) {
        String string = "     ";

        String sha256Crypt = Sha2Crypt.sha256Crypt(string.getBytes());
        System.out.println(sha256Crypt);//$5$AFoQTeyt$TiqmobvcQXjXaAQMYosAAO4KI8LfigZMGHzq.Dlp4NC

    }
}

4.BCrypt暗号化テスト

package   Tester;

import java.security.SecureRandom;
import java.util.Map;
import java.util.UUID;

import   Tester.util.BcryptCipher;
import   Tester.util.MD5Utils;

/**
 * BCrypt  
 */
public class BCryptTest {

    public static void main(String[] args) {

        String string = "     ";
        Map bcrypt = BcryptCipher.Bcrypt(string);
        System.out.println(bcrypt.keySet()); //[cipher, salt]

        System.out.println(bcrypt.get("cipher")); //$2a$12$ylb92Z84gqlrSfzIztlCV.dK0xNbw.pOv3UwXXA76llOsNRTJsE/.
        System.out.println(bcrypt.get("salt")); //$2a$12$ylb92Z84gqlrSfzIztlCV.

        Map bcrypt2 = BcryptCipher.Bcrypt(bcrypt.get("salt"),string);
        System.out.println(bcrypt2.get("SALT_KEY")); //null
        System.out.println(bcrypt2.get("CIPHER_KEY")); //null   
    }
}