Google Cloud Storage - JAVA REST API - Getting SignatureDoesNotMatch - google-cloud-storage

Question

I am using jersey-client to make REST Call . I am getting SignatureDoesNotMatch error in response.
I was trying to List down Bucket names using GET Service , also tried to list Bucket object using GET Bucket method.
here is my sample code.
Any hint or solution ?
public class restSample {
private static final String HMAC_SHA1_ALGORITHM = "HmacSHA1";
private static final String PROJECT_ID = "10XXXXXXXX478";
public static String Base64Encoding()
throws java.security.SignatureException, UnsupportedEncodingException {
String access_id = "GOOGBAXXXXXXXXXXBI";
String secret_key = URLEncoder.encode("pWTXXXXXXXXXXXXXXXRo85T+XXXXXXXXX3O","UTF-8");
String bucket = "bucket_name";
String version_header = "x-goog-api-version:1";
String project_header = "x-goog-project-id:"+PROJECT_ID;
String canonicalizedResources = "/"+bucket+"/";
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.MINUTE, 30);
long expiration = calendar.getTimeInMillis();
String stringToSign = URLEncoder.encode("GET\n\n\n"+expiration+"\n"+version_header+"\n"+project_header+"\n"+canonicalizedResources,"UTF-8");
//String stringToSign = URLEncoder.encode("GET\n\n\n"+getdate()+"\n"+version_header+"\n"+project_header+"\n"+canonicalizedResources,"UTF-8");
String authSignature="";
try {
SecretKeySpec signingKey = new SecretKeySpec(secret_key.getBytes(),HMAC_SHA1_ALGORITHM);
Mac mac = Mac.getInstance(HMAC_SHA1_ALGORITHM);
mac.init(signingKey);
// compute the hmac on input data bytes
byte[] rawHmac = mac.doFinal(stringToSign.getBytes("UTF-8"));
// base64-encode the hmac
authSignature = new String(Base64.encode(rawHmac));
} catch (Exception e) {
throw new SignatureException("Failed to generate HMAC : " + e.getMessage());
}
authSignature = (access_id +":"+ authSignature);
return authSignature;
}
public static void main(String[] args) {
ClientConfig config = new DefaultClientConfig();
Client client = Client.create(config);
String authSignature = null;
try {
authSignature = "GOOG1 "+ Base64Encoding();
} catch (SignatureException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
WebResource service = client.resource(getBaseURI());
ClientResponse response = service.accept(MediaType.APPLICATION_XML)
.header("Authorization",authSignature)
.header("Date", getdate())
.header("Content-Length", "0")
.header("x-goog-api-version", "1")
.header("x-goog-project-id", PROJECT_ID)
.get(ClientResponse.class);
System.out.println(response.getClientResponseStatus().getFamily());
System.out.println("response1 :: " + response.getEntity(String.class));
}
private static URI getBaseURI() {
String url = "https://bucket_name.storage.googleapis.com";
return UriBuilder.fromUri(url).build();
}
private static String getdate(){
SimpleDateFormat format = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z ", new Locale("US"));
Calendar cal = Calendar.getInstance(new SimpleTimeZone(0, "GMT"));
format.setCalendar(cal);
return format.format(new Date());
}
}
Thanks!

Answer 1

Make sure the string you are signing matches the expected string to sign. Google cloud storage returns the expected string to sign in the HTTP response if authentication fails.
In your particular example it looks like you are adding both the version_header and project_header into the string to sign. These are not in the list of CanonicalHeaders nor CanonicalExtensionHeaders, so you are signing a different string than the server.
You can review the list here: https://developers.google.com/storage/docs/reference/v1/developer-guidev1#authentication