Method for processing access-request message for packet service

1. A method for processing an access-request message for packet service, comprising:

writing a temporary randomly generated authenticator value in an attribute field of an access-request message;

encrypting a user password using the temporary authenticator value;

executing an encryption algorithm using the access-request message having the temporary authenticator value and the encrypted user password to generate a message digest, the access-request message having an authenticator field that is filled with a prescribed value;

generating a final access-request message, the final access-request message being generated by using the access-request message and replacing the value of the authenticator field with the message digest;

transmitting the final access-request message to an Authentication, Authorization and Accounting (AAA) server; and

verifying the final access-request message by the AAA server using the prescribed value,

wherein the prescribed value is a value previously defined between a foreign agent and the AAA server.

2. The method of claim 1 , wherein verifying the final access-request message comprises:

temporarily storing the value of the authenticator field of the final access-request message;

filling the authenticator field with the prescribed value;

performing an encrypting algorithm to obtain a second message digest; and

verifying the access-request message by comparing the temporarily stored value of the authenticator field to the second message digest.

3. The method of claim 2 , wherein verifying the final access-request message further comprises:

determining the final access-request message to be normal if the temporarily stored authenticator value and the second message digest are identical to each other; and

determining the final access-request message to be abnormal if the temporarily stored authenticator value and the second message digest are not identical to each other.

4. The method of claim 3 , further comprising:

processing the final access-request message if the final access-request message is normal; and

performing a user authentication by decrypting the encrypted user password written in the attribute field of the processed final access-request message.

5. The method of claim 4 , wherein performing the user authentication comprises:

decrypting the encrypted user password written in the attribute field of the final access-request message using the temporary authenticator value of the final access-request message;

comparing the decrypted user password with the user password stored in a data base;

determining the user authentication to be successful if the decrypted user password and the stored user password are identical to each other; and

determining the user authentication to have failed if the decrypted user password and the stored user password are not identical to each other.

6. The method of claim 3 , further comprising discarding the final access-request message if the final access-request message is determined to be abnormal.

7. The method of claim 1 , wherein the randomly generated authenticator value is randomly generated every time a message is generated.

8. A method for processing an access-request message for a packet service in a communication system, comprising:

writing an authenticator value for authenticating an access-request message in an authenticator field of an access-request message and transmitting an access-request message;

verifying the access-request message by using the authenticator value of the access-request message when the access-request message is received;

processing the access-request message if the access-request message is successfully verified; and

performing user authentication by decrypting an encrypted user password of the processed access-request message using a temporary authenticator value of the processed access-request message and a shared secret key that is known to each of a message transmitter and a message receiver.

9. The method of claim 8 , wherein verifying the access-request message comprises:

temporarily storing the authenticator value written in the authenticator field of the received access-request message;

replacing the authenticator value with a prescribed value in the authenticator field, the prescribed value being previously defined between the message transmitter and the message receiver to form a verification access-request message;

performing an encrypting algorithm using the verification access-request message and the shared secret key to form a message digest; and

comparing the message digest with the temporarily stored authenticator value, wherein the access-request message is verified if the message digest and the authenticator value are identical to each other, and wherein the access-request message is abnormal if the message digest and the authenticator value are not identical to each other.

10. The method of claim 8 , wherein performing user authentication comprises:

decrypting the encrypted user password written in an attribute field of the processed access-request message using the temporary authenticator value of the processed access-request message;

comparing the decrypted user password and a user password stored in a database;

determining that the user authentication is successful if the decrypted user password and the stored user password are identical to each other; and

determining that the user authentication has failed if the decrypted user password and the stored user password are not identical to each other.

11. The method of claim 8 , wherein transmitting the access-request message comprises:

encrypting a user password using the temporary authenticator value;

creating the authenticator value for authentication of the access-request message using the temporary authenticator value and a prescribed value previously defined between the message transmitter and the message receiver; and

writing the authenticator value in the authenticator field and generating the access-request message.

12. The method of claim 11 , wherein encrypting the user password comprises:

generating an arbitrary value which is arbitrarily created each time a message. is generated as a temporary authenticator value;

writing the temporary authenticator value in the attribute field of the access-request message; and

encrypting the user password using the temporary authenticator value and the shared secret key.

13. The method of claim 11 , wherein generating the authenticator value comprises:

forming the access-request message by filling attribute fields of the access-request message with the temporary authenticator value and the encrypted user password, and filling the authenticator field with the prescribed value;

executing an encryption algorithm using the generated access-request message and the shared secret key to form a message digest; and

taking the message digest as the authenticator value.

14. The method of claim 11 , wherein the temporary authenticator value is randomly generated each time a new access-request message is generated, such that the temporary authenticator value is not known beforehand.

15. The method of claim 8 , wherein the message transmitter is a Foreign Agent (FA) and wherein the message receiver is an Authentication, Authorization, and Accounting (AAA) server.

16. A method of processing an access-request message, comprising:

receiving an access-request message having a code field, an identifier field, a length field, and authenticator value, and at least one attribute field, the authenticator value being a message digest created by encrypting a temporary access-request message, and the at least one attribute field including an encrypted user password;

processing the authenticator value to determine if the access-request message is a valid access-request message or an abnormal access-request message; and

performing user authentication if it is determined that the access-request message is a valid access-request message and discarding the access-request message if it is determined that the access-request message is abnormal.

17. The method of claim 16 , wherein the access-request message is formed by writing a temporary randomly generated authenticator value in a first attribute field of a temporary access-request message, writing a prescribed value into an authenticator field of the temporary access-request message and writing the encrypted password into a second attribute field, encrypting the user password using the temporary authenticator value, executing an encryption algorithm on the temporary access-request message to form a message digest, replacing the temporary authenticator value of the temporary access-request message with the message digest to form the access-request message.

18. The method of claim 16 , wherein processing the authenticator value comprises:

temporarily storing the authenticator value written in the authenticator field of the received access-request message;

replacing the authenticator value with a prescribed value in the authenticator field to form a verification access-request message, the prescribed value being previously defined between the message transmitter and the message receiver;

performing an encrypting algorithm using the verification access-request message and a shared secret key to form a message digest; and

comparing the message digest with the temporarily stored authenticator value, wherein the access-request message is verified if the message digest and the authenticator value are identical to each other, and wherein the access-request message is abnormal if the message digest and the authenticator value are not identical to each other.

19. An improved method of processing an access-request message at a message receiving point, the improvement comprising authenticating the access-request message prior to performing user authentication of the access-request message such that abnormal access-request messages are not processed for user authentication,

wherein authenticating the access-request message comprises:

temporarily storing contents of an authenticator field of the access-request message;

filling the authenticator field with a prescribed value known to each of a message origination point and the message receiving point to form a temporary access-request message;

performing an encrypting algorithm on the temporary access-request message to obtain a message digest; and

verifying the access-request message by comparing the temporarily stored authenticator value to the message digest.

20. The improvement of claim 19 , wherein verifying the access-request message comprises determining the access-request message to be normal if the authenticator value and the message digest are identical to each other, and determining the access-request message to be abnormal if the authenticator value and the message digest are not identical to each other.

21. The method of claim 20 , wherein if the access-request message is determined to be abnormal based on the authentication procedure, the access-request message is discarded, and wherein if the access-request message is determined to be normal, the message is processed for user authentication.