Difference between revisions of "Updox HMAC Authentication"

Latest revision as of 07:33, 8 July 2014

Description

For enhanced security, Updox provides an additional layer of authentication using a keyed-hash message authentication code (HMAC) with SHA1 as the cryptographic hash function. This document outlines how to use the Updox HMAC-SHA1 authentication.

Note: Updox HMAC-SHA1 enhances the Individual and Application Authorization schemes, it does not replace it. The auth header in the body of the post is still required for authorizing as a vendor, account, and user.

Outline

The Updox HMAC-SHA1 authentication layer requires two http header fields for every request:

1. updox-timestamp - the current time in the format "yyyy-MM-dd HH:mm:ss (z)".

2. Authorization - "HMAC " + the Base64 encoded HMAC SHA1 hash of the message with the secret key. Note the <SPACE> character following the letters HMAC.

The message is defined as (implementation shall exclude brackets):

 [vendorId]:[vendorPassword]:[accountId]:[userId]:[updox-timestamp]

where [accountId] and [userId] are required to be part of the string to be hashed for each each request. If either of the accountId or userId are not used or populated, their place-holder in the message to be hashed must still be provided. In other words (excluding the 2 colons in the timestamp value) there should always be five values and four colons in the message to be hashed.

Example Messages To Be Hashed

For the following examples, each uses a timestamp value of 2013-11-20 17:36:00 (GMT)

Verification

Updox will verify two things:

1. The timestamp header (updox-timestamp) is within the minutes defined for the vendor (defaults to 10 minutes).

2. The hash passed in matches the hash we compute (therefore, the message was signed with the secret key).

Code Samples

      public void setHmacHeaders(HttpWebRequest request)
       {
           string applicationId = "vendor-id";
           string applicationPassword = "vendor-password";
           string accountId = "accountId";
           string userId = "userId";
           string apiSecret = "vendor-private-secret-key"; 
 
           // Create the date string
           String timestampString = DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss") + " (GMT)"
  
           // Build authentication string
           string message = 
                applicationId + ":" + 
                applicationPassword + ":" + 
                accountId + ":" + 
                userId + ":" + 
                timestampString; 
 
           // Create the athentication hash - note the intentional <space> after HMAC
           string auth = "HMAC " + hmacSha1ToBase64(message, apiSecret);  //
 
           // Set the request headers
           request.Headers.Add("updox-timestamp", timestampString);
           request.Headers.Add("Authorization", auth);
       }
 
       public string hmacSha1ToBase64(String value, String key)
       {
           // Get an hmac_sha1 key from the raw key bytes
           byte[] keyBytes = Encoding.UTF8.GetBytes(key);
           byte[] valueBytes = Encoding.UTF8.GetBytes(value);
               
             
           // Get an hmac_sha1 Mac instance and initialize with the signing key
           HMACSHA1 myhmacsha1 = new HMACSHA1();
 
           myhmacsha1.Key = keyBytes;
 
           byte[] final = myhmacsha1.ComputeHash(valueBytes);
 
           // Covert array of Hex bytes to a String
           return Convert.ToBase64String(final);
       }

   public static void generateHmacHeaders(HttpURLConnection connection, String applicationId, String applicationPassword, String accountId, String userId) throws Exception{
       final SimpleDateFormat d = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss (z)");
       d.setTimeZone(TimeZone.getTimeZone("GMT"));
       final String timestampString = d.format(new Date());
       final String message = 
          (applicationId == null ? "" : applicationId) + ":" + 
          (applicationPassword == null ? "" : applicationPassword) + ":" + 
          (accountId == null ? "" : accountId) + ":" + 
          (userId == null ? "" : userId) + ":" + 
          timestampString;
       final String auth = "HMAC " + hmacSha1ToBase64(message, apiSecret); //note space after HMAC
       connection.setRequestProperty("updox-timestamp", timestampString);  
       connection.setRequestProperty("Authorization", auth);
   }
   
   public static String hmacSha1ToBase64(String value, String key) throws Exception{
       byte[] keyBytes = key.getBytes();
       SecretKeySpec signingKey = new SecretKeySpec(keyBytes, "HmacSHA1");
       Mac mac = Mac.getInstance("HmacSHA1");
       mac.init(signingKey);
       byte[] rawHmac = mac.doFinal(value.getBytes());
       byte[] base64Bytes = Base64.encodeBase64(rawHmac);
       return new String(base64Bytes, "UTF-8");
   }

Messages (Example)

Destination Address

 https://updoxqa.com/io/pingWithApplicationAuth

Request and Response

Headers Construction

The message to be hashed is constructed thusly (note that while the accountId and userId values are not provided to the pingWithAuth API call, their placeholders are still present in the message to be hashed):

applicationId:applicationPassword:::2013-11-20 17:36:00 (GMT)

It is then hashed with the vendor's secret key:

vendorSecretKey applied to message to be hashed results in output (note that this hash string is not the actual result of encrypting the sample data):

fH2JyYwiERQbwXL4XF6ZvtLjRvQ=

HMAC authentication data is delivered to Updox as headers on the JSON request transaction:

Headers

 updox-timestamp: 2013-11-20 17:36:00 (GMT)
 
 Authorization: HMAC fH2JyYwiERQbwXL4XF6ZvtLjRvQ=
 
 Content-type: application/json

Note that the Content-type header is not part of HMAC encryption, but a standard header required when sending JSON data.

Request

{
    "auth": {
        "applicationId": "applicationId",
        "applicationPassword": "applicationPassword",
        "accountId": "",
        "userId": ""
    }
}

Response

{
    "successful": true,
    "responseMessage": "OK",
    "responseCode": 2000
}

Relevant Response Codes

In addition to the General Error Set, this method may return the following values in the responseCode and responseMessage fields: