Free SOA S90.20 Exam Dumps Questions & Answers

Service Consumer A sends a request message to Service A (1), after which Service A sends a request message with security credentials to Service B (2). Service B authenticates the request and, if the authentication is successful, writes data from the request message into Database B (3). Service B then sends a request message to Service C (4), which is not required to issue a response message. Service B then sends a response message back to Service A (5). After processing Service B's response, Service A sends another request message with security credentials to Service B (6). After successfully authenticating this second request message from Service A, Service B sends a request message to Service D (7). Service D is also not required to issue a response message. Finally, Service B sends a response message to Service A (8), after which Service A records the response message contents in Database A (9) before sending its own response message to Service Consumer A (10).

To use Service A, Service Consumer A is charged a per usage fee. The owner of Service Consumer A has filed a complaint with the owner of Service A, stating that the bills that have been issued are for more usage of Service A than Service Consumer A actually used.
Additionally, it has been discovered that malicious intermediaries are intercepting and modifying messages being sent from Service B to Services C and D.
Because Services C and D do not issue response messages, the resulting errors and problems were not reported back to Service B.
Which of the following statements describes a solution that correctly addresses these problems?

• A.  Messages sent to Services C and D must be protected using transport-layer encryption in order to ensure data confidentiality. Service consumers of Service A must be authenticated using X.509 certificates because they can be reused for several request messages.
• B.  The Data Confidentiality and Data Origin Authentication patterns need to be applied in order to establish message-layer confidentiality and integrity for messages sent to Services C and D.
  The Direct Authentication pattern can be applied to require that service consumer be authenticated in order to use Service A.
• C.  Apply the Brokered Authentication to establish an authentication broker between Service Consumer A and Service A that can carry out the Kerberos authentication protocol. Before invoking Service A, Service Consumer A must request a ticket granting ticket and then it must request service granting tickets to all services in the service composition, including Services C and D.
  Messages sent by Service B to Services C and D must further be encrypted with the public key of Service Consumer A.
• D.  Apply the Service Perimeter Guard and the Message Screening patterns together to establish a perimeter service between Service Consumer A and Service A.
  The perimeter service screens and authenticates incoming request messages from Service Consumer A.
  After successful authentication, the perimeter service generates a signed SAML assertion that is used by the subsequent services to authenticate and authorize the request message and is also carried forward as the security credential included in messages sent to Services C and D.

Service Consumer A sends a request message to Service A (1), after which Service A sends a request message with security credentials to Service B (2). Service B authenticates the request and, if the authentication is successful, writes data from the request message into Database B (3). Service B then sends a request message to Service C (4), which is not required to issue a response message. Service B then sends a response message back to Service A (5). After processing Service B's response, Service A sends another request message with security credentials to Service B (6). After successfully authenticating this second request message from Service A, Service B sends a request message to Service D (7). Service D is also not required to issue a response message. Finally, Service B sends a response message to Service A (8), after which Service A records the response message contents in Database A (9) before sending its own response message to Service Consumer A (10).

Services A and B use digital certificates to support message integrity and authentication.
With every message exchange between the two services (2, 5, 6, 8), the digital certificates are used. It has been determined that both Databases A and B are vulnerable to malicious attackers that may try to directly access sensitive data records. Furthermore, performance logs have revealed that the current exchange of digital certificates between Services A and B is unacceptably slow.
How can the integrity and authenticity of messages exchanged between Services A and B be maintained, but with improved runtime performance - and - how can Databases A and B be protected with minimal additional impact on performance?

• A.  Apply the Direct Authentication pattern to establish mutual authentication between Services A and B using a shared identity store. Service A attaches a Username token to the first request message sent to Service B and Service B authenticates the request message using the shared identity store. Similarly, when Service B submits a response message to Service A.
  it attaches its own Username token that Service A then authenticates by also using the same shared identity store. Database A is encrypted using the Service A password as a secret encryption key and Database B is encrypted using the Service B password as a secret encryption key.
• B.  Apply the Brokered Authentication pattern to establish an authentication broker that uses WS-Trust based SAML tokens for message exchanges between Services A and B.
  This eliminates the need for Service A to be repeatedly authenticated by Service B.
  Use the public key of Service A to encrypt Database A and use the public key of Service B to encrypt Database B.
• C.  Apply the Brokered Authentication pattern to establish an authentication broker that uses WS-SecureConversation security context tokens (SCTs) to generate and transmit a symmetric session key. The session key is used to encrypt and digitally sign messages exchanged between Services A and B.
  For each database the Trusted Subsystem pattern is applied to require authenticated access to the database and to prevent attackers from accessing the database directly
• D.  Apply the Brokered Authentication pattern to establish an authentication broker that uses WS-Trust based SAML tokens for message exchanges between Services A and B.
  This eliminates the need for Service A to be repeatedly authenticated by Service B.
  Database A is encrypted using the Service A password as a secret encryption key and Database B is encrypted using the Service B password as a secret encryption key.

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 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.
• 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.  None of the above

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.