Accept: application/vnd.boacompra.com.v1+json; charset=UTF-8
Content-Type: application/json
Accept-Language: en-US
Authorization: 10:05eddbf68e09cb3d339b08a8e478c020d50d7c3604ad3da67def785e9399daaa

public class Header {
  private String secretKey = "YOURSECRETKEY";
  private String storeId = "10";
  private String contentMD5;
  private String httpVerb;

  public Header(String url, String content) throws NoSuchAlgorithmException, MalformedURLException, UnsupportedEncodingException {
    this.setContentMd5(content);
    this.setHttpVerb(new URL(url));
  }

  private void setHttpVerb(URL url) {
    this.httpVerb = url.getPath() + (url.getQuery() != null ? url.getQuery() : "");
  }

  private void setContentMd5(String content) throws NoSuchAlgorithmException, UnsupportedEncodingException {
    if (content == "") {
      this.contentMD5 = "";
    }else {
      MessageDigest md = MessageDigest.getInstance("MD5");
      byte messageDigest[] = md.digest(content.getBytes("UTF-8"));
      this.contentMD5 = Base64.encodeBase64String(new BigInteger(1,messageDigest).toString(16).getBytes());
    }
  }

  private String generateAuthorization() throws NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException {
    final String data = this.httpVerb+this.contentMD5;
    Mac mac = Mac.getInstance("HmacSHA256");
    mac.init(new SecretKeySpec(this.secretKey.getBytes("UTF8"), "HmacSHA256"));
    return Hex.encodeHexString(mac.doFinal(data.getBytes("UTF-8")));
  }

  public HashMap<String,String> generateHeader() throws InvalidKeyException, NoSuchAlgorithmException, UnsupportedEncodingException {
    HashMap<String, String> headers = new HashMap<>();

    headers.put("Accept", "application/vnd.boacompra.com.v1+json; charset=UTF-8");
    headers.put("Content-Type", "application/json");
    headers.put("Authorization", this.storeId+':'+this.generateAuthorization());
    headers.put("Accept-Language", "en-US");

    return headers;
  }
}

Header header = new Header("https://api.boacompra.com/transactions/87585840", "");
HashMap<String, String> headerMap = header.generateHeader();
System.out.println(Arrays.asList(headerMap));

<?php

class header {

    private $_secretKey = 'YOURSECRETKEY';
    private $_storeId = '10';

    function __construct($url, $content = '') {
        $this->_setContentMd5($content);
        $this->_setHttpVerb($url);
    }

    private function _setContentMd5($content) {
        if ($content == '') $this->_contentMd5 = '';
        else $this->_contentMd5 = base64_encode(md5($content));
    }

    private function _getQueryString($url){
        $queryString = parse_url($url, PHP_URL_QUERY);
        return empty($queryString) ? '' : '?' . $queryString;
    }

        private function _setHttpVerb($url) {
        $this->_httpVerb = parse_url($url, PHP_URL_PATH) . $this->_getQueryString($url);
    }

    private function _generateAuthorization() {
        return hash_hmac('sha256', $this->_httpVerb . $this->_contentMd5, $this->_secretKey);
    }

    public function generateHeader() {
        $headers = array(
        'Accept' => 'application/vnd.boacompra.com.v1+json; charset=UTF-8',
        'Content-Type' => 'application/json',
        'Authorization' => $this->_storeId.':'.$this->_generateAuthorization(),
        'Accept-Language' => 'en-US'
        );
        return $headers;
    }
}

echo '<pre>'. 'GET EXAMPLE <br />';
$headerGet = new header('https://api.boacompra.com/transactions/87585840', '');

print_r($headerGet->generateHeader());

require 'uri'
require 'base64'
require 'openssl'
require 'digest/md5'

class Header

   SECRET_KEY = 'YOURSECRETKEY'
   STORE_ID = 10

   attr_reader :contentMD5, :httpVerb

   def initialize(url, content = '')
    setContentMD(content)
    setHttpVerb(url)
   end

   private
   def setContentMD(content)
      if content.to_s.empty?
          @contentMD5 = ''
      else
          @contentMD5 = Base64.encode64(Digest::MD5.hexdigest(content)).delete!("\n")
      end
   end

   private
   def getQueryString(url)
    uri = URI(url)
    url.to_s.empty? || uri.query.nil? ? '' : '?' + uri.query
   end

   private
   def setHttpVerb(url)
    uri = URI::parse(url)
    @httpVerb = uri.path + getQueryString(url)
   end

   private
   def generateAuthorization()
    OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha256'), SECRET_KEY, @httpVerb + @contentMD5)
   end

   public
   def generateHeader()
    headers = {
     "Accept"           => 'application/vnd.boacompra.com.v1+json; charset=UTF-8',
     "Content-Type"     => 'application/json',
     "Authorization"    => STORE_ID.to_s + ":" + generateAuthorization(),
     "Accept-Language"  => 'en-US'
    }
    headers
   end
end

puts '<pre>GET EXAMPLE <br />'
headerGet = Header.new('https://api.boacompra.com/transactions/87585840', '')
puts headerGet.generateHeader()

"""Boacompra python 2.7"""
import base64
import hashlib
import hmac

from urlparse import urlparse

class Header:
  secretKey = "YOURSECRETKEY"
  storeId = "10"

  def __init__(self, url, content):
    self.setContentMd5(content)
    self.setHttpVerb(url)

  def setContentMd5(self, content):
    self.contentMd5 = '' if content == '' else base64.b64encode(hashlib.md5(content).hexdigest())

  def setHttpVerb(self, url):
    self.httpVerb = '{}''{}'.format(urlparse(url).path, self.getQueryStrint(url))

  def getQueryStrint(self, url):
    return '' if urlparse(url).query == '' else '?{}'.format(urlparse(url).query)

  def generateAuthorization(self):
    return hmac.new(self.secretKey, self.httpVerb + self.contentMd5, hashlib.sha256).hexdigest()

  def generateHeader(self):
    return dict({'Accept':'application/vnd.boacompra.com.v1+json; charset=UTF-8', 'Content-Type':'application/json', 'Authorization': '{}'':{}'.format(self.storeId, self.generateAuthorization()), 'Accept-Language':'en-US'})


"""Boacompra python 3.x"""
import base64
import hashlib
import hmac

from urllib.parse import urlparse

class Header3(object):
  secretKey = "YOURSECRETKEY"
  storeId = "10"

  def __init__(self, url, content):
    self.setContentMd5(content)
    self.setHttpVerb(url)
    self.generateAuthorization()

  def setContentMd5(self, content):
    self.contentMd5 = ''
    if content == ''
    else base64.b64encode(hashlib.md5(content.encode()).hexdigest().encode('ascii')).decode('ascii')

  def setHttpVerb(self, url):
    self.httpVerb = '{}''{}'.format(urlparse(url).path, self.getQueryStrint(url))

  def getQueryStrint(self, url):
    return '' if urlparse(url).query == '' else '?{}'.format(urlparse(url).query)

  def generateAuthorization(self):
    message = bytes('{}''{}'.format(self.httpVerb, self.contentMd5), 'utf-8')
    secret = bytes(self.secretKey, 3 'utf-8')

    return hmac.new(secret, message, hashlib.sha256).hexdigest()

  def generateHeader(self):
    return dict({'Accept':'application/vnd.boacompra.com.v1+json; charset=UTF-8', 'Content-Type':'application/json', 'Authorization': '{}'':{}'.format(self.storeId, self.generateAuthorization()), 'Accept-Language':'en-US'})

POST http://your-virtual-store.com/transaction-notification/ HTTP/1.1
Host: boacompra.com
Content-Length:86
Content-Type: application/x-www-form-urlencoded
transaction-code=1234567890
notification-type=transaction

{
    "transaction-result": {
        "store-id": "10",
        "transactions": [
            {
                "transaction-code": "87990145",
                "order-id": " 1500397602",
                "order-description": "Purchase Test",
                "status": "REFUNDED",
                "currency": "BRL",
                "amount": "10.00",
                "customer-email": "test@boacompra.com",
                "customer-country": "BR",
                "notify-url": "https://loja_teste.boacompra.com/consume_notifications.php",
                "payment-country": "BR",
                "payment-id": "3",
                "payment-name": "mastercard",
                "order-date": "2017-07-18T14:18:44-03:00",
                "payment-date": "2017-07-18T14:21:02-03:00",
                "last-status-change-date": "2017-07-18T14:30:10-03:00",
                "chargeback-date": null,
                "refundable": false,
                "refunds": [
                    {
                        "refund-id": "32926",
                        "refund-status": "PROCESSED",
                        "refund-amount": "10.00",
                        "refund-date": "2017-07-18T14:21:47-03:00",
                        "refund-processing-date": "2017-07-18T00:00:00-03:00",
                        "refund-reference": "BC-34134"
                    }
                ],
                "payment-methods": [
                    {
                        "code": "123E4567E89B12D3A456426655440000",
                        "date-created": "2018-04-11T11:31:11.571488493-03:00",
                        "credit-card": {
                            "brand": "visa",
                            "masked-number": "************0002",
                            "expiration-date": "2026-12"
                        }
                    }
                ]
            }
        ]
    },
    "metadata": {
        "found": "1",
        "page-results": 1,
        "current-page": 1,
        "total-pages": 1
    }
}

{
    "errors": [
        {
            "code": "17078",
            "description": "currency_not_accepted"
        }
    ]
}

POST http://your-virtual-store.com/transaction-notification/ HTTP/1.1
Host: boacompra.com
Content-Length:86
Content-Type: application/x-www-form-urlencoded
transaction-code=1234567890
notification-type=transaction
test-mode=true