How does one generate an HMAC string in Elixir? - hmac

I'm attempting to write an Amazon Product Advertising API client in Elixir. The developer guide describes the process for signing an API request in which the an HMAC-SHA26 hash must be created using the request and the "Secret Access Key." This is the function I wrote to handle signing the request:
defp sign_request(url) do
url_parts = URI.parse(url)
request = "GET\n" <> url_parts.host <> "\n" <> url_parts.path <> "\n" <> url_parts.query
url <> "&Signature=" <> :crypto.hmac(:sha256, 'ThisIsMySecretAccessKey', request)
end
The url passed into the function looks something like this: http://webservice.amazon.com/onca/xml?AssociateTag=ThisIsMyAssociateTag&AWSAccessKeyId=ThisIsMyAWSAccessKeyId&Keywords=stuff&Operation=ItemSearch&SearchIndex=Apparel&Service=AWSECommerceService&Timestamp=2014-11-22T12%3A00%3A00Z&Validate=True&Version=2013-08-01
The issue I'm having is that, while:crypto.hmac/3 returns a binary, that binary is not a string; passing the return value to String.valid?/1 returns false. So, I am unable to concatenate the return value onto the end of the url string to sign the request.
Am I using :crypto.hmac/3 incorrectly? Is there something I'm missing? Is there an alternate way I should be going about this?

When you using :crypto.hmac/3 its return base 16 integer in binary format, your problem could be solved like this:
:crypto.mac(:hmac, :sha256, "key", "The quick brown fox jumps over the lazy dog")
|> Base.encode16
This is match example from https://en.wikipedia.org/wiki/Hash-based_message_authentication_code#Examples_of_HMAC_.28MD5.2C_SHA1.2C_SHA256.29

Related

MS Access API Request

This is my first post here though have been using the great advice/solutions here for years so am very grateful. But this one, I can't find solution for.
I have an MS access front end/back end in use for various office admin tasks and records. Much of the data my office works with on a daily basis is cloud based. However API access is provided with app key and secret key. I have no issues using the API explorer with these keys, but can't get anything through code (VBA). I keep reading it is perfectly possible to do this with VBA which is why I kept trying different solutions, but now need help. (I have replaced URL and keys etc)
Dim myObj As New MSXML2.XMLHTTP60
Dim url, endPoint, params, tickers, appKey, secretKey As String
url = "theURL.com"
endPoint = "theEndPoint"
params = "id="
tickers = "1"
appKey = "12345678"
secretKey = "12345678"
myObj.Open "GET", url, False
myObj.setRequestHeader "Content-Type", "application/json"
myObj.setRequestHeader "app-key", appKey
myObj.setRequestHeader "secret-key", secretKey
myObj.send
This returns "App Key is required." I have tried various solutions including converting keys to Base64, putting the keys within the Open request, sending the keys as part of the send request etc. Always get "App Key is required" when reading response. I know in this code I have't actually requested anything but that returns same message when I do. I just wanted to keep what I posted simple.
Any help at all is greatly appreciated as this would allow great deal of automation for our office.
Thanks
James

Format this GET request in VB.NET code behind?

I am trying a "GET" method to request a count of activities from the Accelo API here:
https://api.accelo.com/docs/?http#count-activities
And although i've used a very similar POST method to successfully get the access token using an authentication method, I cannot for the life of me figure out how to get the count of activities. The API says to use "GET" and past the access token as "bearer..." and I've also tried doing a post and getting the stream first, tried sending in some data and accessing the "list activities" endpoint instead...nothing is working. everything I do returns the error "400. Bad Request."
I've tried passing data in a query string format directly in the URI, and tried passing no data since its a GET function. It looks to me like I'm following the API exactly.
Dim data2 = Nothing ' Encoding.UTF8.GetBytes(jsonstring)
Dim _list = GetListOfActivities(New Uri("https://example.api.accelo.com/api/v0/activities/count.xml"), data2, _AccessToken)
Dim reqa As WebRequest = WebRequest.Create(uri)
' reqa.Method = "GET"
reqa.Headers.Add("GET", "/api/v0/activities/count.xml HTTP/1.1")
reqa.Headers.Add("Authorization", "Bearer " & _AccessToken)
reqa.ContentType = "application/x-www-form-urlencoded"
'reqa.ContentLength = jsonDataBytes.Length
' Dim streama = reqa.GetRequestStream()
' streama.Write(jsonDataBytes, 0, jsonDataBytes.Length)
'streama.Close()
Dim responsea As WebResponse = reqa.GetResponse()
Console.WriteLine((CType(responsea, HttpWebResponse)).StatusDescription)
I must be formatting the request wrong - please help?
My problem turned out to be something stupid, and literally beyond the scope of what I posted here. I had specified a "scope" in my initial request to get the access token that was set to read-only "staff" data (I had copied-and-pasted their example online into my code, for other parameters like grant type, and I brought the scope along with it), and in this scenario here I was trying to access "activities" data and not "staff" data. I would have thought I'd get a permissions-related error, instead of "bad request" which confused me, but anyway it works now.
The above code - actually with this line:
reqa.Method = "GET"
instead of this line:
reqa.Headers.Add("GET", "/api/v0/activities/count.xml HTTP/1.1")
Works just fine since I changed my scope to read(all) in my initial web method getting the access token.

Why does Stripe.com return error (402) Payment Required?

I'm not seeing this particular error described in stripes API anywhere. Anyone know what's going on?
Here is my VB.net code to create a customer:
Function CreateStripeCustomer(ByVal Token As String) As String
'' The Stripe Account API Token - change this for testing
Dim STR_Stripe_API_Token As String = "sk_test_SECRET_TEST_KEY" '<-- test secret key. Change to live later.
''The Stripe API URL
Dim STR_Stripe_API_URL As String = "https://api.stripe.com/v1/customers"
''Creates a Web Client
Dim OBJ_Webclient As New System.Net.WebClient()
''Creates Credentials
Dim OBJ_Credentials As New System.Net.NetworkCredential(STR_Stripe_API_Token, "MY_STRIPE.COM_PASSWORD")
''Sets the Credentials on the Web Client
OBJ_Webclient.Credentials = OBJ_Credentials
''Creates a Transaction with Data that Will be Sent to Stripe
Dim OBJ_Transaction As New System.Collections.Specialized.NameValueCollection()
OBJ_Transaction.Add("email", "PERFECTLY_VALID_EMAIL")
OBJ_Transaction.Add("card", "PERFECTLY VALID TOKEN RETURNED BY STRIPE.JS")
''The Stripe Response String
Dim STR_Response As String = Encoding.ASCII.GetString(OBJ_Webclient.UploadValues(STR_Stripe_API_URL, OBJ_Transaction))
Return STR_Response
End Function
The 402 "payment required" error is happening on the line:
Dim STR_Response As String = Encoding.ASCII.GetString(OBJ_Webclient.UploadValues(STR_Stripe_API_URL, OBJ_Transaction))
If you're seeing this in live, it's also possible the card number is simply incorrect, eg: if you inspect the body of the 402 response:
Well, I switched to my "LIVE" keys instead of my "TEST" keys, and that fixed it. Just wasted 3 hours of my life trying to fix this. Hope this helps somebody else.
The more correct answer is that you need to use the appropriate test card numbers. See https://stripe.com/docs/testing
Stripe provides a test environment in which you use the test publishable/secret keys, as oppose to waiting till production. However, what seems like the down side, which is in fact very helpful is that you need to comply to Stripe's testing conditions and use their given card numbers and inputs to test different aspects of your api call.
For example, in order to receive certain errors you can input these numbers:
card_declined: Use this special card number - 4000000000000002.
incorrect_number: Use a number that fails the Luhn check, e.g. 4242424242424241.
invalid_expiry_month: Use an invalid month e.g. 13.
invalid_expiry_year: Use a year in the past e.g. 1970.
invalid_cvc: Use a two digit number e.g. 99.
For more information refer to the link that Samir posted.
For iOS
If you are following tutorial from Ray Wunderlich website the reason why error may appear is that you run your test back end (web.rb file) and after that add you TEST_SECRET_KEY.
Go to the terminal click control+C, make sure you have already added your TEST_SECRET_KEY, save file and do ruby web.rb.
For now, everything should work fine.
For reference, I used this number of the card for testing: 4242 4242 4242 4242

Authenticate in Xero from Salesforce

I'm new to Oauth and I stack on getting oauth_access_token to work with Xero. Web Service authentication doesn't work for me.
Xero returns the following error message "oauth_problem=signature_invalid&oauth_problem_advice=Failed to validate signature".
The generated signature is incorrect, but what is right way to generate it?
Here is APEX code which generates Endpoint. What is wrong?
Http h = new Http();
String consumer_key='XXX';
Long tmp=(System.now().getTime()/1000);
Blob isItCorrect = Crypto.generateMac('HMacSHA1', Blob.valueOf('https://api.xero.com/api.xro/2.0'), Blob.valueOf(consumer_key));
String signature= EncodingUtil.urlEncode(EncodingUtil.base64Encode(isItCorrect), 'UTF-8');
// Try to get access token
HttpRequest req = new HttpRequest();
req.setEndpoint('https://api.xero.com/oauth/RequestToken?oauth_consumer_key='+consumer_key+
'&oauth_signature_method=RSA-SHA1'+
'&oauth_signature='+signature+
'&oauth_timestamp='+tmp+ '&oauth_nonce='+tmp+'&oauth_version=1.0&scope=https%3A%2F%2Fapi.xero.com%2Fapi.xro%2F2.0');
req.setMethod('GET');
// Send the request, and return a response
HttpResponse res = h.send(req);
System.debug('~~~ '+res.getBody());
It generates following Endpoint:
Endpoint=https://api.xero.com/oauth/RequestToken?oauth_consumer_key=ICSP7Y5K2TG7RIIC6Y7R7KLC1AHWYC&oauth_signature_method=RSA-SHA1&oauth_signature=gWP02y2EIatw4xilTvd5Iq3e0%2Fw%3D&oauth_timestamp=1372123781&oauth_nonce=1372123781&oauth_version=1.0&scope=https%3A%2F%2Fapi.xero.com%2Fapi.xro%2F2.0
Just as an aside: I've never worked with salesforce so I'm not sure if there's a better
way to leverage existing oauth work on the platform, it's very rare
now to have to write all the oauth signature stuff yourself and it's
easy to make a mistake but here goes]
I think your signature base string is incorrect.
As far as I can tell you're just performing HMAC-SHA1 over https://api.xero.com/api.xro/2.0
if you read the OAuth Spec here: http://oauth.net/core/1.0/#anchor14 you need to construct the following base string (based on the request above)
GET&https%3A%2F%2Fapi.xero.com%2Foauth%2Frequesttoken&oauth_consumer_key%3DCONSUMER_KEY%26oauth_nonce (etc etc, just append all your query parameters apart from oauth_consumer as url encoded key=value pairs, in alphabetical order)
and then you need to create the hash with the key CONSUMER_KEY&CONSUMER_SECRET (both CONSUMER_KEY and CONSUMER_SECRET should be parameter encoded as per the OAuth Spec)
That should give you a valid signature..
Edit: I found this library which might be of help: https://code.google.com/p/sfdc-oauth-playground/

Problems Connecting to MtGox API 2 with Python

I am writing a trading program that I need to connect to MtGox (a bitcoin exchange) through the API v2. But I keep getting the following error:
URL: 1 https://data.mtgox.com/api/2/BTCUSD/money/bitcoin/address
HTTP Error 403: Forbidden.
Most of my script is a direct copy from here (that is a pastebin link). I just had to change it to work with Python 3.3.
I suspect that it has to do with the part of script where I use base64.b64encode. In my code, I have to encode my strings to utf-8 to use base64.b64encode:
url = self.__url_parts + '2/' + path
api2postdatatohash = (path + chr(0) + post_data).encode('utf-8') #new way to hash for API 2, includes path + NUL
ahmac = base64.b64encode(str(hmac.new(base64.b64decode(self.secret),api2postdatatohash,hashlib.sha512).digest()).encode('utf-8'))
# Create header for auth-requiring operations
header = {
"User-Agent": 'Arbitrater',
"Rest-Key": self.key,
"Rest-Sign": ahmac
}
However, with the other guy's script, he doesn't have too:
url = self.__url_parts + '2/' + path
api2postdatatohash = path + chr(0) + post_data #new way to hash for API 2, includes path + NUL
ahmac = base64.b64encode(str(hmac.new(base64.b64decode(self.secret),api2postdatatohash,hashlib.sha512).digest()))
# Create header for auth-requiring operations
header = {
"User-Agent": 'genBTC-bot',
"Rest-Key": self.key,
"Rest-Sign": ahmac
}
I'm wondering if that extra encoding is causing my header credentials to be incorrect. I think this is another Python 2 v. Python 3 problem. I don't know how the other guy got away without changing to utf-8, because the script won't run if you try to pass a string to b64encode or hmac. Do you guys see any problems with what I am doing? Is out code equivalent?
This line specifically seems to be the problem -
ahmac = base64.b64encode(str(hmac.new(base64.b64decode(self.secret),api2postdatatohash,hashlib.sha512).digest()).encode('utf-8'))
To clarify, hmac.new() creates an object to which you then call digest(). Digest returns a bytes object such as
b.digest()
b'\x92b\x129\xdf\t\xbaPPZ\x00.\x96\xf8%\xaa'
Now, when you call str on this, it turns to
b'\\x92b\\x129\\xdf\\t\\xbaPPZ\\x00.\\x96\\xf8%\\xaa'
So, see what happens there? The byte indicator is now part of the string itself, which you then call encode() on.
str(b.digest()).encode("utf-8")
b"b'\\x92b\\x129\\xdf\\t\\xbaPPZ\\x00.\\x96\\xf8%\\xaa'"
To fix this, as turning bytes into a string back into bytes was unnecessary anyhow(besides problematic), I believe this will work -
ahmac = base64.b64encode(hmac.new(base64.b64decode(self.secret),api2postdatatohash,hashlib.sha512).digest())
I believe you are likely to find help in a related question of mine although it deals with the WebSocket API:
Authenticated call to MtGox WebSocket API in Python 3
Also, the HTTP 403 error seems to indicate that there is something fundamentally wrong with the request. Even if you threw the wrong authentication info at the API you should have gotten an error message as a response and not a 403. My best guess is that you are using the wrong HTTP method so check if you are using the appropriate one (GET/POST).