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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. 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.
• 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 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.
• D. None of the above

Service Consumer A sends a request to Service A (1). Service A replies with an acknowledgement message (2) and then processes the request and sends a request message to Service B (3). This message contains confidential financial data. Service B sends three different request messages together with its security credentials to Services C.
D.
and E (4, 5, 6). Upon successful authentication, Services C.
D. and E store the data from the message in separate databases (7.8, 9). Services B.
C.D, and E belong to Service Inventory A, which further belongs to Organization B.
Service Consumer A and Service A belong to Organization A.

Organization B decides to create a new service inventory (Service Inventory B) for services that handle confidential data. Access to these services is restricted by allocating Service Inventory B its own private network. Access to this private network is further restricted by a dedicated firewall. Services C, D and E are moved into Service Inventory B, and as a result. Service B can no longer directly access these services.
How can this architecture be changed to allow Service B to access Services C, D and E in a manner that does not jeopardize the security of Service Inventory B while also having a minimal impact on the service composition's performance?

• A. The Data Confidentiality pattern is applied together with the Direct Authentication pattern. A new utility service is created to validate request messages sent to Service Inventory B.
  Service B must encrypt the message content using the utility service's public key and attach its own digital certificate to the request message. This message is first evaluated by the firewall to filter out requests from disallowed sources and can then be forwarded to the utility service, which then verifies the identity of the message originator (using a digital certificate) and decrypts the request message contents. If the originator is authorized to access Services C, D, and E, the appropriate request messages are sent to these services.
• B. The Service Perimeter Guard pattern is applied together with the Brokered Authentication pattern. A new perimeter service is created to intercept all request messages sent to services inside the private network (inside Service Inventory B), before they reach the firewall. The perimeter service also acts as the authentication broker that authenticates request messages sent to Services C, D, and E by evaluating the accompanying security credentials and issuing a security token to be used by Service B when accessing Services C, D, and E.
• C. The Service Perimeter Guard pattern is applied together with the Message Screening pattern. A new perimeter service is created specifically for Service Inventory B.
  This service filters all messages before they reach the firewall and further evaluates the IP address of the messages to verify the identity of the message originators. If the originator is successfully authenticated, then the perimeter guard checks the request message for potentially malicious content. If the request message does not contain malicious content, it is sent through the firewall to proceed to Services C, D, and E for further processing.
• D. The Brokered Authentication pattern is applied by extending the firewall functionality with a single sign-on mechanism. Because the firewall already restricts accesses to Service Inventory B, adding authentication logic to the firewall optimizes the performance of the overall security architecture. Service B needs to be authenticated by the authentication broker only once in order to get a security token that can be used to access Services C, D, and E.
  This eliminates the need for Service B to authenticate several times during the same service composition.

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. 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.
• D. 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.