Francois Lascelles

Last week, I had the pleasure of discussing REST access control patterns with Enterprise Architects and partnering technology folks. I also had the opportunity to present on this topic and one of the questions that came up afterwards was from a security architect who was unsure whether OAuth would be a good fit for some existing APIs that they have because those APIs happen to be consumed from two very different sources: from the inside, by internal applications that do not act on behalf of a particular subscriber but from the provider’s perspective from the outside, by applications that act on behalf of individual subscribers OAuth 2.0 provides 4 core grant types that address different situations. In the case of the example described above, you could use the client creds grant type for the first type of access. It should be possible to permit different scopes to dif... (more)

OAuth Token Management

Tokens are at the center of API access control in the Enterprise. Token management, the process through which the lifecycle of these tokens is governed emerges as an important aspect of Enterprise API Management. OAuth access tokens, for example, can have a lot of session information associated to them: scope; client id; subscriber id; grant type; associated refresh token; an SAML assertion or other token the oauth token was mapped from; how often it’s been used, from where. While some of this information is created during OAuth handshakes, some of it continues to evolve througho... (more)

Flexible Identity Federation XML Gateways to The Rescue

Imagine a fresh business relationship between ACME Corporation and Partner. As a result of this relationship, ACME wants to grant Partner limited access to one of its core internal applications. They do this, naturally, by exposing a Web service. Why Identity Federation? Boris (an employee at Partner) sends a SOAP request to the ACME Web service along with some password or proof-of-possession type credentials. Because Boris's identity is managed outside of ACME, those credentials cannot be authenticated using ACME's authentication infrastructure. To circumvent this issue, one cou... (more)

WS Security Performance

The WS Secure Conversation specification describes a mechanism letting multiple parties establish a context (using the WS Trust Request Security Token standard) and secure subsequent SOAP exchanges. Each WS Secure Conversation session has an associated shared secret. Instead of using this shared secret directly to sign and encrypt the conversation's messages, symmetric keys are derived from the secret itself. Deriving new keys for each message and different keys for signature and encryption limits the amount of data that an attacker can analyze in attempting to compromise the con... (more)

Standardize HMAC, OAuth RESTful Authentication Schemes

As the enterprise is increasingly taking notice of WOA (Web Oriented Architecture) these days, the need for security guidelines and standards for RESTful Web services is becoming more pressing. Sure, RESTful Web services are meant to borrow existing security mechanisms from the web and HTTP Basic over SSL, when done right, is a great way to accomplish shared-secret based authentication. Yet, for better or for worse, it is common to find REST API providers defining their own authentication mechanisms. Take for example the Amazon S3 REST API’s custom HTTP authentication scheme. Us... (more)