Google OAuthGetRequestToken returns "signature_invalid" - oauth

Question

Trying for hours to get a request token using Google OAuthGetRequestToken but it always returns "signature_invalid".
For a test I use the oAuth Playground to successfully request the token. Here are the results:
Signature base string
GET&https%3A%2F%2Fwww.google.com%2Faccounts%2FOAuthGetRequestToken&oauth_callback%3Dhttp%253A%252F%252Fgooglecodesamples.com%252Foauth_playground%252Findex.php%26oauth_consumer_key%3Dwww.embeddedanalytics.com%26oauth_nonce%3D56aa884162ed21815a0406725c79cf79%26oauth_signature_method%3DRSA-SHA1%26oauth_timestamp%3D1321417095%26oauth_version%3D1.0%26scope%3Dhttps%253A%252F%252Fwww.google.com%252Fanalytics%252Ffeeds%252F
Request/Response
GET /accounts/OAuthGetRequestToken?scope=https%3A%2F%2Fwww.google.com%2Fanalytics%2Ffeeds%2F HTTP/1.1
Host: www.google.com
Accept: */*
Authorization: OAuth oauth_version="1.0", oauth_nonce="56aa884162ed21815a0406725c79cf79", oauth_timestamp="1321417095", oauth_consumer_key="www.embeddedanalytics.com", oauth_callback="http%3A%2F%2Fgooglecodesamples.com%2Foauth_playground%2Findex.php", oauth_signature_method="RSA-SHA1", oauth_signature="qRtorIaSFaQdOXW1u6eMQlY9LT2j7ThG5kgkcD6rDcW4MIvzluslFgYRNTuRvnaruraNpItjojtgsrK9deYRKoHBGOlU27SsWy6jECxKczcSECl3cVAcjk7dvbywFMDkgi1ZhTZ5Q%2BFoD60HoVQUYnGUbOO0jPXI48LfkiA5ZN4%3D"
HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8
Date: Wed, 16 Nov 2011 04:18:15 GMT
Expires: Wed, 16 Nov 2011 04:18:15 GMT
Cache-Control: private, max-age=0
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Content-Length: 118
Server: GSE
oauth_token=4%2FmO86qZzixayI2NoUc-hewC--D53R&oauth_token_secret=r0PReF9D83w1d6uP0nyQQm9c&oauth_callback_confirmed=true
I am using Fiddler to trace my calls. It returns the Signature base string:
GET&https%3A%2F%2Fwww.google.com%2Faccounts%2FOAuthGetRequestToken&oauth_callback%3Dhttp%253A%252F%252Fgooglecodesamples.com%252Foauth_playground%252Findex.php%26oauth_consumer_key%3Dwww.embeddedanalytics.com%26oauth_nonce%3Dl9Jydzjyzt2fJfM3ltY5yrxxYy2uh1U7%26oauth_signature_method%3DRSA-SHA1%26oauth_timestamp%3D1321417107%26oauth_version%3D1.0%26scope%3Dhttps%253A%252F%252Fwww.google.com%252Fanalytics%252Ffeeds%252F
Aside from the oauth_timestamp and oauth_nonce (which should be different), the base string are pretty much identical.
Anyone know what I am doing wrong?
Update 11/20/2011 Thinking it might be something wrong with my RSA-SHA signing, I have since tried HMAC-SHA. It gives the same results. I thought it might be beneficial to include the Fiddler results (I added carriage returns to have it format better).
GET https://www.google.com/accounts/OAuthGetRequestToken?
scope=https%3A%2F%2Fwww.google.com%2Fanalytics%2Ffeeds%2F HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Authorization: OAuth oauth_version="1.0",
oauth_nonce="7C4C900EAACC9C7B62E399A91B81D8DC",
oauth_timestamp="1321845418",
oauth_consumer_key="www.embeddedanalytics.com",
oauth_signature_method="HMAC-SHA1",
oauth_signature="ows%2BbFTNSR8jVZo53rGBB8%2BfwFM%3D"
Host: www.google.com
Accept: */*
Accept-Encoding: identity
Response
HTTP/1.1 400 Bad Request
Content-Type: text/plain; charset=UTF-8
Date: Mon, 21 Nov 2011 03:16:57 GMT
Expires: Mon, 21 Nov 2011 03:16:57 GMT
Cache-Control: private, max-age=0
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Content-Length: 358
Server: GSE
signature_invalid
base_string:GET&https%3A%2F%2Fwww.google.com%2Faccounts%2FOAuthGetRequestToken
&oauth_consumer_key%3Dwww.embeddedanalytics.com
%26oauth_nonce%3D7C4C900EAACC9C7B62E399A91B81D8DC
%26oauth_signature_method%3DHMAC-SHA1
%26oauth_timestamp%3D1321845418
%26oauth_version%3D1.0
%26scope%3Dhttps%253A%252F%252Fwww.google.com%252Fanalytics%252Ffeeds%252F
Update 11/24/2011 - I want to add more information based on the answers from #Meysam and #Bob Aman. First, my domain is properly registered with Google. I have been using AuthSub for quite some time now with Target URL path prefix set to http://www.embeddedanalytics.com/authsubsuccess.html. Now when I go to the Manage Domains section it states my oAuth consumer key is www.embeddedanalytics.com. Now perhaps this could be a problem. In the Registration for Web-Based Applications document it states:
If you're using the OAuth interface, this URL (the "Target URL path prefix") must match the value of the oauth_consumer_key parameter
In my case I have a target URL different from my oauth_consumer_key. Could this be a problem? I use www.embeddedanalytics.com as the consumer_key in the playground and it works. I don't want to mess with the target URL because it is currently being used with my AuthSub authorizations.

Answer 1

I assume you have not registered your application domain with Google. Therefore, whatever consumer secret you are using to sign your request (in HMAC-SHA1 method) will be denied unless you provide anonymous as your oauth_consumer_key and consumer secret. This way, Google will recognize you as an unregistered application and will successfully return you a Request Token.
If you use the HMAC-SHA1 method, the Consumer Secret and Token Secret will be used to sign your requests. These two secret parameters are known both to your application, and Google, and act like a secret key in a symmetric encryption algorithm.
In order to use RSA-SHA1 method however, you should have already uploaded your Public Key to the server (Google Server) during the registration process of your application. After that, you will use your Private Key to sign your OAuth requests. In your case, since you have not registered your application, Google is not aware of your Public Key, and therefore using RSA-SHA1 method to sign your requests with an unknown Private Key is of no use.
The first method is usually preferred over the RSA-SHA1 method for performance reasons. (symmetric encryption is faster than asymmetric one)
So this is the way I could successfully get a Request Token in the OAuth Playground:
Set 'oauth_consumer_key' to anonymous (unless you have
registered your application and have a real Consumer Key)
Set 'consumer secret' to anonymous (unless you have registered your
application and have a real Consumer Secret)
Choose https://www.google.com/analytics/feeds/ as the scope of request.
Press 'Request token' button
Result:
GET /accounts/OAuthGetRequestToken?scope=https%3A%2F%2Fwww.google.com%2Fanalytics%2Ffeeds%2F HTTP/1.1
Host: www.google.com
Accept: */*
Authorization: OAuth oauth_version="1.0", oauth_nonce="116d4df85e784f51cf40f0bc3a967883", oauth_timestamp="1322083727", oauth_consumer_key="anonymous", oauth_callback="http%3A%2F%2Fwww.googlecodesamples.com%2Foauth_playground%2Findex.php", oauth_signature_method="HMAC-SHA1", oauth_signature="vVxpbtHlTR%2BJ1yT%2BYS1HOvRzhOs%3D"
HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8
Date: Wed, 23 Nov 2011 21:28:47 GMT
Expires: Wed, 23 Nov 2011 21:28:47 GMT
Cache-Control: private, max-age=0
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Content-Length: 118
Server: GSE
oauth_token=4%2F7E_YtZFHuKFPbuAGuCzyj2AsHcha&oauth_token_secret=NHZBJCj2BPxR2HQZhCTwdq2A&oauth_callback_confirmed=true
Now that you have acquired oauth_token and oauth_token_secret, you can press Authorize button. This will redirect you to the login page of Google (if you are not signed in) and then to the page you grant access to the application. By granting access, you will get back to the callback url in the playground with a verifier code. Pressing 'Access token' button, will get you the access token:
GET /accounts/OAuthGetAccessToken HTTP/1.1
Host: www.google.com
Accept: */*
Authorization: OAuth oauth_version="1.0", oauth_nonce="c222a88cc9f027430b239f4cc6f3f154", oauth_timestamp="1322084080", oauth_consumer_key="anonymous", oauth_verifier="TA6vWcDJC51A9YwMNfmUzmUQ", oauth_token="4%2F7E_YtZFHuKFPbuAGuCzyj2AsHcha", oauth_signature_method="HMAC-SHA1", oauth_signature="q9M%2BjeHNxB2ONPd1DPMn6GriUC8%3D"
HTTP/1.1 200 OK
Content-Type: text/plain; charset=UTF-8
Date: Wed, 23 Nov 2011 21:34:40 GMT
Expires: Wed, 23 Nov 2011 21:34:40 GMT
Cache-Control: private, max-age=0
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Content-Length: 103
Server: GSE
oauth_token=1%2Fxy49iwSQEcqSDbo3cKO-UuPLqvt9qKFit9vaLqR6P-M&oauth_token_secret=IJWB1CVSQfYJJPrf9jXv6SS8
*Note: One time, I got the signature_invalid response too, even though I had entered anonymous credentials. But after trying again and pressing 'Request token' button one or two more times I made it. I think this should be due to how nonce and timestamp parameters work to sign the request. This could be the cause of problem. Read this article for more info.
Further reading:
Managing the OAuth key and secret
Registration for Web-Based Applications

Answer 2

Googler here. Haven't fielded OAuth 1 questions in a long time because everyone's moving to OAuth 2 (and you should too) but I'll try to go through the usual suspects on invalid signature errors:
Your server's clock may be wrong. There's a timestamp component and it needs to match ours pretty closely. Try updating your clock against one of the major reference time servers. This happens, but it's an uncommon issue.
Depending on how low-level the OAuth client you're using is, you may have forgotten to supply part of the key used to generate the signature. The key has two pieces, colon-separated, IIRC. In some parts of the protocol, only one half is needed, but for other parts of the protocol, you need both. I've seen cases where someone kept supplying only the first half when both were needed. Actually, I think I made this mistake myself a couple times.
Probably not an issue in your case, because you haven't even gotten past the request token, but OAuth 1 requires you to sign the URI query parameters. Failure to do this will cause the signature base strings to mismatch, thus causing the signature to be invalid.
By far the most common issue is improper encoding. This usually gets expressed as signatures that work sometimes, but fail other times, because sometimes you get lucky and nothing needs to get encoded. I suspect this is what #Meysam ran into based on his comment that he pressed the button a few more times and suddenly it worked.
By the way, if you have to use OAuth 1, you should be using HMAC-SHA1 unless you've got a really good reason to do RSA-SHA1.