Service A is a publically accessible service that provides free multimedia retrieval capabilities to a range of service consumers. To carry out this functionality, Service A is first invoked by Service Consumer A (1). Based on the nature of the request message received from Service Consumer A, Service A either invokes Service B or Service C.
When Service B is invoked by Service A (2A) it retrieves data from publicly available sources (not shown) and responds with the requested data (3A). When Service C is invoked by Service A (2B) it retrieves data from proprietary sources within the IT enterprise (not shown) and responds with the requested data (3B). After receiving a response from Service B or Service C, Service A sends the retrieved data to Service Consumer A (4).
Service B does not require service consumers to be authenticated, but Service C does require authentication of service consumers. The service contract for Service A therefore uses WS-Policy alternative policies in order to express the two different authentication requirements to Service Consumer A.
When Service Consumer A sends a request message (1), Service A determines whether the request requires the involvement of Service C and then checks to ensure that the necessary security credentials were received as part of the message. If the credentials provided by Service Consumer A are verified. Service A creates a signed SAML assertion and sends it with the request message to Service C (2B) This authentication information is protected by public key encryption However, responses to Service Consumer A's request message (3B, 4) are not encrypted for performance reasons.

The owner of Service C is planning two changes to the service architecture: 1. A fee will be charged to Service Consumer A (or any service consumer) using Service C.
2. The response messages issued by Service C need to be secured in order to prevent unauthorized access. An analysis of Service C's usage statistics reveals that a group of service consumers specifically request the retrieval of multimedia data on a frequent basis.
To promote the usage of Service C to these types of service consumers, the owner of Service C plans to offer a special discount by allowing unlimited multimedia retrievals for a fixed monthly price. Service consumers that do not subscribe to this promotion will need to pay for each request individually. It is anticipated that the new promotion will significantly increase the usage of Service C.
The owner of Service C therefore wants to ensure that the security added to the response messages has a minimal impact on Service C's runtime performance.
What steps can be taken to fulfill these requirements?

• A. Design the service composition architecture so that the encryption of the response messages is performed by Service B and Service C.
  To reduce the performance impact, a policy can be added to Service A's service contract in order to require the encryption of all response messages, regardless of the type of service consumer making the request.
  Further, a new utility service can be added to the service composition. This service can be responsible for obtaining the public key of the service consumer and forwarding the key along with the request message to the appropriate service (Service B or Service C). The service receiving the message can then encrypt the response message with the received public key. Service A can then forward the encrypted response to the service consumer.
  This approach ensures that only authorized service consumers will be able to access response messages.
• B. Because the services in this service composition already rely on public key encryption to provide authentication, Service C can provide message confidentiality by encrypting the response message with Service Consumer A's public key. This will ensure that only the intended recipient, in possession of the corresponding private key, can decrypt the response message. To further reduce the performance impact of encryption, Service C can generate a new public-private key pair to be used by service consumers subscribed to the promotion. By securely distributing the private key to each of these service consumers, Service C only needs to encrypt the response messages once with the public key.
• C. Design Service C to generate a message digest of the response message and encrypt it with the service consumer's public key. Because the message digest is typically small, the performance of public key encryption is acceptable. This approach also ensures that only the service consumer can decrypt the response message using the corresponding private key.
• D. Use symmetric session keys so that for each response message, Service C generates a session key and encrypts the response message using this session key. The session key is then encrypted (using the service consumer's public key) and attached to the encrypted response. A single session key can then be used by Service C for communication with all service consumers that subscribe to the promotion.

Service A provides a customized report generating capability. Due to infrastructure limitations, the number of service consumers permitted to access Service A concurrently is strictly controlled. Service A validates request messages based on the supplied credentials (1). If the authentication of the request message is successful, Service A sends a message to Service B (2) to retrieve the required data from Database A (3). Service A stores the response from Service B (4) in memory and then issues a request message to Service C (5). Service C retrieves a different set of data from Database A (6) and sends the result back to Service A (7). Service A consolidates the data received from Services B and C and sends the generated report in the response message to the service consumer (8).

It has been discovered that attackers have been gaining access to confidential data exchanged between Service A and Service B, and between Service A and its service consumers. What changes can be made to this service composition architecture in order to counter this threat?

• A. None of the above
• B. Apply the Service Perimeter Guard pattern in order to protect message exchanges between Service A and its service consumers. Apply the Direct Authentication pattern in order to protect message exchanges between Service A and Service B.
• C. Apply the Direct Authentication pattern in order to protect message exchanges between Service A and its service consumers and between Service A and Service B.
  This approach will establish a password-based authentication mechanism that relies on a local identity store and will therefore prevent access by attackers.
• D. Apply the Data Origin Authentication pattern to protect the final report sent by Service A to its service consumer. Service A can generate a message digest of the final report, after which it can sign the digest with its own private key. It then can send both the final report and the signed message digest to its service consumer. This service consumer can generate its own message digest, decrypt the signed digest using the public key of Service A (which proves that Service A sent the message), and then compare the two digests. If the digests match, it guarantees that the final report was not tampered with during transmission.

Services A, B, and C reside in Service Inventory A and Services D, E, and F reside in Service Inventory B.
Service B is an authentication broker that issues WS-Trust based SAML tokens to Services A and C upon receiving security credentials from Services A and
C. Service E is an authentication broker that issues WS-Trust based SAML tokens to Services D and F upon receiving security credentials from Services D and E.
Service B uses the Service Inventory A identify store to validate the security credentials of Services A and C.
Service E uses the Service Inventory B identity store to validate the security credentials of Services D and F.

To date, the two service inventories have existed independently from each other. However, a requirement has emerged that the services in Service Inventory A need to be able to use the services in Service Inventory B, and vice versa.
How can cross-service inventory message exchanges be enabled with minimal changes to the existing service inventory architectures and without introducing new security mechanisms?

• A. The current security mechanism already fulfills the requirement because SAML tokens can be used across multiple security domains. The only change required is for each authentication broker to be configured so that it issues service inventory-specific assertions for SAML tokens originating from other service inventories.
• B. The individual domain service inventories need to be combined into one enterprise service inventory. The Service Perimeter Guard pattern can be applied to establish a contact point for request messages originating from outside the service inventory. Within the service inventory, services no longer need to be authenticated because they are all part of the same trust boundary.
• C. The Trusted Subsystem pattern is applied to encapsulate Services B and E using a central utility service that balances request and response messages exchanged between Services B and E, depending on which service inventory the messages originate from. The utility service also contains transformation logic to ensure that the SAML tokens issued by Services B and E are compatible. This guarantees that an issued SAML token can be used across Service Inventories A and B without further need for runtime conversion.
• D. Because SAML tokens cannot be used across multiple security domains, authentication brokers C and E need to be replaced with one single authentication broker so that one token issuer is used for all services across both of the service inventories.