Content Comparison

package com.sunwave;


import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.SimpleDateFormat;
import java.util.Base64;
import java.util.TimeZone;
import java.util.Date;

public class DigestCreator {
    private String userId;
    private String clientId;
    private String clientSecret; // Realm Private Key "select client_secret from sw_external_application where client_id = ? and clinic_id = ?
    private String clinicId;

    private String transactionId; //"select id from sw_api_transaction where transaction_id = ? and clinic_id = ?"

    private String payload;


    private String createMd5Digest() throws NoSuchAlgorithmException {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(payload.getBytes());
        return md.digest().toString();
    }
    private String createSeed() throws NoSuchAlgorithmException, UnsupportedEncodingException {
        String seed = null;
        if (payload == null) {
            seed = userId + ":" + clientId + ":" + getDateTimeBase64() + ":" + clinicId + ":" + transactionId;
        } else {
            seed = userId + ":" + clientId + ":" + getDateTimeBase64() + ":" + clinicId + ":" + transactionId + ":" + createMd5Digest();
        }
        return seed;
    }

    private String getDateTimeBase64() throws UnsupportedEncodingException {
        SimpleDateFormat df = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z");
        df.setTimeZone(TimeZone.getTimeZone("GMT"));
        Date d = new Date();
        java.sql.Timestamp now = new java.sql.Timestamp(new java.util.Date().getTime());
        String dateTime = df.format(now);
        byte[] encodedDate = Base64.getEncoder().encode(dateTime.getBytes());
        return new String(encodedDate, "UTF8");
    }

    private String createTransactionId() {
        return null;
    }

    private String createToken() throws UnsupportedEncodingException, NoSuchAlgorithmException, InvalidKeyException {
        return userId + ":" + clientId + ":" + getDateTimeBase64() + ":" + clinicId + ":" + transactionId + ":" + createHMAC(createSeed());
    }

    private String createHMAC(String message) throws UnsupportedEncodingException, NoSuchAlgorithmException, InvalidKeyException {
        byte[] byteKey = clientSecret.getBytes("UTF-8");
        final String HMAC_SHA512 = "HmacSHA512";
        Mac sha512_HMAC = Mac.getInstance(HMAC_SHA512);
        SecretKeySpec keySpec = new SecretKeySpec(byteKey, HMAC_SHA512);
        sha512_HMAC.init(keySpec);
        byte[] mac_data = sha512_HMAC.
            doFinal(message.getBytes("UTF-8"));
        return Base64.getUrlEncoder().encodeToString(mac_data);
    }


    public DigestCreator(String userId, String clientId, String clientSecret, String clinic_id, String transactionId, String payload) {
        this.userId = userId;
        this.clientId = clientId;
        this.clientSecret = clientSecret;
        this.clinicId = clinic_id;
        this.transactionId = transactionId;
        this.payload = payload;
    }

    public static void main( String args[] ) throws UnsupportedEncodingException, NoSuchAlgorithmException, InvalidKeyException {
        if ((args.length < 5) || (args.length > 6)) {
            System.out.println("usage: java -cp . org.baudekin.DigestCreator user_id clinic_id client_id, client_secret, transaction_id, <pay load>");
            System.exit(-1);
        }
        String payload = null;
        // We are doing post
        if (args.length == 6) {
            payload = args[5];
        }

        DigestCreator dc = new DigestCreator(args[0], args[2], args[3], args[1], args[4], payload);
        System.out.println("Token: " + dc.createToken());
        System.exit(0);
    }


}