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Claims  |
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What is claimed is:
1. A method of operating a distributed computer system having alias
detection, comprising the steps of:
A) storing, in a user account store of said computer system, identification
information associated with each of a plurality of user accounts, said
identification information for each said user account uniquely
characterizing a computer user associated with said account;
B) storing a list of selected ones of said user accounts in an
authorization store;
C) after steps (A) and (B), initiating execution of a computer system
resources access program in response to a request on behalf of a first of
said user accounts; and
D) after step (C), processing said request from said first user account for
authorizing access to a computer system resource by performing the steps
of
i) comparing said identification information stored in said user account
store in association with said first user account and identification
information associated with each of said user accounts of said list of
selected user accounts, and
ii) executing said computer system access program if said compared
identification information do not match, thereby indicating that said
first user account is not an alias of any of said selected user accounts.
2. A method in accordance with claim 1, wherein said identification
information for each said user account includes authenticating
information, digitized biometric information, and user account
information.
3. A method in accordance with claim 2, further comprising the step of:
an account registrar verifying said digitized biometric information prior
to a representation of said digitized biometric information being stored
in a said user account store.
4. A method in accordance with claim 2, further including the step of
creating said user accounts, and said accounts creation step includes said
account registrar verifying step.
5. A method in accordance with claim 2, further comprising the step of:
an account registrar digitally signing said digitized biometric information
and said authenticating information and said user account information
prior to said digitally signed information being stored in said user
account store.
6. A method in accordance with claim 1, wherein said step of initiating
execution of a computer systems access program comprises the steps of:
E) comparing a validation credential linking said access program to user
certificates of said selected user accounts in said authorization store to
determine whether said user account is authorized to execute said access
program; and
F) allowing said user account to execute said access program if authorized
to do so.
7. A method in accordance with claim 1, wherein said executing step
includes the step of permitting access to said computer resource if said
compared identification information do not match.
8. A method in accordance with claim 1, wherein said processing step
further comprises the step of:
denying said request if said compared identification information match,
thereby indicating that said first user account is an alias of at least
one of said selected user accounts.
9. A method in accordance with claim 1, wherein said processing step
further comprises the step of:
denying said request on the occurrence of any of the following events: i)
said user account is the same as one of said selected user accounts, ii)
said user account has no associated identification information in said
user account store, and iii) said user account's identification
information in said user account store is the same as one of said selected
user account's identification information.
10. A method of operating a distributed computer system having alias
detection, comprising the steps of:
A) storing, in respective user accounts a user account store of said
computer system identification information associated with each of a
plurality of user accounts, said identification information for each said
user account uniquely characterizing a computer user associated with said
account;
B) in response to a first request from a first user account, initiating
execution of a stage of a selected transaction program having a plurality
of stages; and
C) processing a second request from a second user account for authorization
of execution of a subsequent stage of said selected transaction program by
performing the steps of
i) comparing said identification information stored in said user account
store for said first user account and said identification information
stored in said user account store for said second user account, and
ii) denying authorization to said second user account if said compared
identification information do match, thereby indicating that said second
user account is an alias of said first user account.
11. A method in accordance with claim 10, wherein said identification
information for each user account contains a digitally-signed account
certificate.
12. A method in accordance with claim 11, wherein said digitally-signed
account certificate includes authenticating information, digitized
biometric information, and user account information.
13. A method in accordance with claim 12, further including the step of:
an account registrar verifying said digitized biometric information prior
to said digitized biometric information being stored in said user account
store.
14. A method in accordance with claim 12, further comprising the step of:
an account registrar digitally signing said digitized biometric
information, said authenticating information and said user account
information prior to said digitized biometric information, said
authenticating information and said user account information being stored
in said user account.
15. A method in accordance with claim 10, wherein said step of initiating a
stage of a transaction program comprises the steps of:
D) comparing a validation credential linking said transaction program to
user certificates of accounts authorized to execute selected transactions
of said transaction program, with a list of authorized user accounts to
determine whether said first user account is authorized to execute said
first stage of said selected transaction program; and
E) allowing said first user account to initiate execution of said first
stage only if authorized to do so.
16. A method according to claim 10, wherein during said processing step,
said request is allowed to execute said subsequent stage of said selected
transaction program if said second user account is not an alias of said
first user account.
17. A method in accordance with claim 10, wherein said processing step
further comprises the step of:
if said first user account is the same as said second user account, or if
said second user account contains has no associated identification
information in said user account store, or if said second user account's
identification information is the same as said first user account's
identification information, denying authorization to said second request.
18. A distributed computer system having alias detection, comprising:
A) a registry store of respective user accounts, said accounts containing
identification information uniquely characterizing each of a plurality of
computer users;
B) a stored application transaction program having at least two stages
requiring separate initiation requests for execution of said stages;
C) means, responsive to a first user account transaction initiation
request, for executing one stage of said application program;
D) means, responsive to an approval of a second user account transaction
initiation request, for executing a subsequent stage of said application
program; and
E) means for comparing identification information of said first and second
user accounts in said store and providing said approval if said compared
identification information do not match, thereby indicating that said
second user account is not an alias of said first user account.
19. A system in accordance with claim 18, further comprising an account
registrar for digitally signing an account certificate included in said
identification information for each said user account.
20. A system accordance with claim 19, wherein said digitally signed
account certificate includes authenticating information and digitized
biometric information and account information.
21. A system in accordance with claim 20, wherein said account registrar
verifies said digitized biometric information prior to said digitized
biometric information being stored in said user account.
22. A system accordance with claim 21, wherein said account registrar
digitally signs said digitized biometric information, said authenticating
information and said user account information prior to said information
being stored in said user account.
23. A system accordance with claim 18, wherein said means responsive to
said first request comprises:
F) means for extracting a delegation certificate from a digitally signed
delegation certificate that associates said first request with a logan
delegation certificate of said first user account;
G) means for verifying said delegation certificate against a list of names
of accounts to determine whether said delegation certificate was generated
on behalf of one of said accounts appearing on said list and is therefore
authorized to execute said first stage of said selected transaction
program; and
H) means for allowing said first user account to initiate execution of said
first stage only if authorized to do so.
24. A system in accordance with claim 18, wherein said means for comparing
comprises: means for terminating said second request in the event said
first user account is the same as said second user account, said second
user account contains no identification information, or said second user
account's identification information is the same as said first use
account's identification information.
25. A distributed computer system for implementing alias detection,
comprising:
A) a store for a plurality of user accounts, said accounts containing
digitally-signed account certificates including authentication
information, digitized biometric information, and user account information
uniquely characterizing, for each said user account, one of a plurality of
computer users;
B) a stored application transaction program having at least two stages
requiring separate initiation requests for execution of said stages;
C) means, responsive to a first user account transaction initiation
request, for executing a first stage of said at least one application
program; and
D) means, responsive to a second user account transaction initiation
request to execute a subsequent stage of said at least one application
program, for comparing said authentication information and said digitized
biometric information contained in said user certificate of said first and
second user accounts in said store; and
E) means for allowing execution of said subsequent stage of said at least
one application program only if said compared authentication information
and digitized biometric information do not match, and thus only if said
second user account is not an alias of said first user account.
26. A system in accordance with claim 25, wherein said digitized biometric
information together with said authenticating information and said user
account information is digitally-signed by an account registrar.
27. A system in accordance with claim 25, wherein said means for comparing
comprises:
means for denying said second request if said first user account is the
same as said second user account, or if said second user account contains
no digitized biometric information, or if said second user account's
identification information is the same as said first user account's
identification information. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
This invention relates to computer systems, and more particularly to a
system for detecting computer user account aliases.
As it is known in the art, effective computer operating system security
measures help prevent unauthorized access to and theft of proprietary
software, software plans, and computer time. These measures can also
protect equipment, software, and computer files from damage caused by
tampering. The source of a security breach on a computer system can
usually be traced to one of three categories: user irresponsibility, user
probing, or user penetration.
User irresponsibility usually refers to situations where an authorized user
purposely or accidently causes some noticeable damage. An example would be
a computer user who is authorized to access certain computer files, makes
an authorized copy of a key file to improperly transfer. This type of
breach can be characterized as a breach of trust. There is little that a
computer operating system can do to protect sites from this source of
security failure, since the initial access to the file was completely
authorized, and the breach occurred by the improper transfer of the fruits
of the authorized access.
User probing refers to situations where a computer user obtains
unauthorized access by exploiting insufficiently protected parts of the
computer system. Probing typically reflects an exploration of top-level
facilities to which a computer user has legitimate access to browse
through the computer system.
User penetration refers to an attempt to bypass existing security controls
by finding relatively obscure flaws in their implementation.
To guard against user probing and user penetration, computer systems
typically include processes to authenticate the identity of a user.
Authentication of a user identity in a computer system is the verification
of a user's identity so that security policies can properly be applied to
requests from that user. Authentication typically involves the examination
of an individual's credentials, such as biometric information,
encryptographic information, and so forth.
In medium- to large-scale distributed computer systems, it is often the
case that a given computer user may well have access to the computer
network via several different computer user accounts, each individually
legitimate. For example, a computer user might have access to the computer
across the network via an employee's computer system in the work place,
and via a personal computer with a modem at home. Where separation of
duties or similar policies are to be enforced by a computer network
server, techniques should exist for the computer network server to
determine whether or not two different computer requests are from distinct
or different individuals. Where one individual can access two or more user
accounts those accounts are known as alias accounts of that one
individual.
An alias, therefore, is defined as an alternate identity for any individual
who is held accountable for his/her actions. Where the possibility of
alias computer user accounts exists, the straightforward comparison of
authentication data, e.g., passwords, public keys, etc., is insufficient
to prevent unwanted aliasing of a user, simply because there are typically
no controls in effect to prevent one user from obtaining distinct user
accounts containing potentially distinct authentication information.
One type of computer security required in many business and commercial
applications has come to be called a policy for the separation of duties.
This policy requires that, for critical business procedures, certain steps
of that business procedure must be performed by different individuals. The
purpose of this policy is to distribute responsibility for a transaction
among several different people so that no one person, acting alone, can
cause the action in question to occur. The presumption is that distinct or
different individuals having different responsibilities will act as checks
on each other.
An example of a policy for the separation of duties which may be
encountered in every day life would be a personal safety deposit box. A
bank usually requires a bank employee and the safety deposit owner to use
two distinct keys and both to sign a log book in order for the safety
deposit box owner to gain access to the safety deposit box. Requiring two
keys is referred to as access control. Requiring both individuals to sign
a log is referred to as audit control. The bank policy is that the owner
and bank employee must be two distinct or different individuals. Another
example would be when a business employee hands in an expense form and
would like to be issued a company check for those expenses. Corporate
policy would require that the expense check may not be signed and
authorized by the same person. These two examples illustrate that the
principle of separation of duties is widely required for manual systems.
Several approaches have been advanced in the past for enforcing separation
of duties policies. The most common approach for enforcement of separation
of duties in automated computer systems has been for a security
administrator to define distinct groups or roles and to manually ensure
that the assignment of the individuals to critical groups or roles does
not overlap. One problem with this approach is that it does not prevent a
threat from a given individual who may have access to a computer system
from two distinct accounts.
Known approaches to the authentication and identification of users by user
account have generally presupposed that user account aliasing is prevented
by the use of operational or procedural rules. Approaches for enforcing a
separation of duties policy have assumed that aliasing does not occur, and
that authenticatible user account identities are therefore sufficient to
identify individuals as well. The problem with this approach is that the
premise that alias accounts do not exist particularly in large computer
systems is generally incorrect.
Moreover, preventing account aliasing becomes more and more impracticable
as networks grow larger and larger. Even if identifying information unique
to an individual, such as biometric information, is obtained when a new
account is created, in order to associate that new user account with any
other user account that may exist for that individual on the network, an
exhaustive search over every user account already in the system would have
to be performed. Such a search is costly even for relatively small
computer networks, and is effectively impossible for large computer
networks.
One further type of user authentication uses biometric reader information
which is fed to the computer system during login. Biometric information is
provided from a biometric reader at each login point or station. A
biometric reader can typically detect unique information or
characteristics of an individual such as eye scans, thumbprints, DNA
sampling, and so forth. While the use of biometric information for
purposes of user authentication is often performed, it is generally
expensive because biometric readers are needed at every login point. In
addition, if biometric information is ever disclosed, there is no way to
undo the damage. For these reasons, continued use of encryptographic
information such as passwords and/or smart cards have usually been
indicated as a better alternative for authentication than biometrics.
SUMMARY OF THE INVENTION
A method of performing alias detection on a computer system, includes the
steps of storing in respective user accounts identification information
uniquely characterizing each of a plurality of computer users, initiating
execution of a computer system resource upon a first request from a first
user account, processing a second request for execution using a second
user account, comparing said identification information stored in said
second user account used during said second request with said
identification information in said first user account, and determining
whether said first user account and said second user account used in said
second request are aliases. With such an arrangement, an alias detection
technique that is performed at the time of execution of a computer
resource using a second request for user account information is provided.
Such a technique can be used for example to control access to restricted
computer resources, monitor and control the existence of alias accounts on
the computer system, and implement a separation of duties policy on
resources of the computer system.
In accordance with a further aspect of the present invention, a method of
operating a distributed computer system includes the steps of storing in
respective user accounts identification information uniquely
characterizing each of a plurality of computer users, storing a list of
selected user accounts in an authorization store, initiating execution of
a computer system resources access program upon request from a user
account, and processing the request from the user account to authorize
access to a plurality of computer system resources by comparing the
identification information stored in the user account and in the list of
authorized user accounts, and determining whether the user account is an
alias of any of the list of authorized user accounts. With such an
arrangement, alias detection is determined at the time that a user
attempts to gain access to a computer system resource.
In accordance with a further aspect of the present invention, a method of
operating a distributed computer system includes the steps of storing in
respective user accounts identification information uniquely
characterizing each of a plurality of computer users, and initiating
execution of a stage of a selected transaction program having a plurality
of stages upon request from a first user account. The method further
comprises the steps of processing a request from a second user account to
authorize execution of a subsequent stage of the selected transaction
program by comparing the identification information stored in the first
user account and in the second user account, and determining whether the
second user account is an alias of the first user account. With such an
arrangement, alias detection is determined at the time that a subsequent
user attempts to complete the selected transaction. By not assuming that
login authentication also uniquely identifies a user, who may, in fact,
have alias accounts, this arrangement provides for detection of aliases at
the point of policy application without ever requiring an exhaustive
search throughout the network for potentially aliased accounts. The
present invention does not assume that user account aliasing is prevented.
Rather, it assumes that alias accounts may be freely created, and uses
data that uniquely identifies the owner of each account to detect the
existence of unwanted aliasing at the point in time just before execution
of a protected activity is to commence.
In accordance with a further aspect of the present invention, a system of
operating a distributed computer system to implement alias detection is
provided, including storing in respective user accounts, digitally-signed
account certificates including identification information uniquely
characterizing each of a plurality of computer users, initiating execution
of one stage of a selected transaction program having a plurality of
stages from a store of application programs on the computer system upon
request from a first user account, processing a request from a second user
account to authorize execution of a subsequent stage of the selected
transaction program by comparing the identification information included
in account certificates stored in the first user account and in the second
user account, determining whether the second user account is an alias of
the first user account, and allowing the processing request to execute the
subsequent stage of the selected transaction program if the second user
account is not an alias of the first user account. With such an
arrangement a computer security system which uses a combination of
biometric and cryptographic techniques is provided. Specifically it
provides a system for supporting a separation of duties policy that is not
dependent on a single authority for registering accounts, or rigorous
account administration to segregate accounts into different
non-overlapping groups or roles (i.e., static enforcement of separation of
duties), or preventing multiple accounts for an individual. Such a system
embodying the invention can support dynamic enforcement of separation of
duties by allowing an individual to assume multiple roles if need be, and
ensure that within the context of a given business function, the
individual has not assumed conflicting roles. It achieves this by the use
of digitized biometric data or other uniquely identifying data to
determine if different accounts are used by a single individual, i.e., are
aliases of each other.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth
in the appended claims. The invention itself, however, as well as other
features and advantages thereof, will be best understood by reference to
the detailed description of specific embodiments which follows, when read
in conjunction with the accompanying drawings, wherein:
FIG. 1 is a diagram in block form of a distributed computer system which
may be used to implement certificate-based alias detection according to
one embodiment of the invention;
FIG. 2 is a diagram in block form of how an account certificate
incorporating certificate-alias detection data is created;
FIG. 3 is a diagram in block form of how certificate-based alias detection
is utilized in the present invention; and
FIG. 4 is a diagram in block form of an example system incorporating
certificate-based alias detection.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, a computer system 10 is depicted with access
available to individual users 10a-10c. Each individual user 10a-10c has a
workstation 12a-12c connected to a local area network 14. The workstations
12a-12c provide each individual user 10a-10c access to a set of
applications to perform his/her duties. The applications reside on an
application server system 16 connected to the local area network 14.
The application server system 16 is a computer system which contains a set
of application programs (hereinafter "applications") that can also be
accessed by other computer users (not shown) via the local area network
14. Each individual user 10a-10c is identified by one or more accounts
maintained in a name service program 19 on a name server system 18.
The name server system 18 is a computer system containing name service
software 19 and accessed by any computer user via the local area network
14. The name service software 19 allows the names of network applications,
systems, and other network-accessible objects to be independent of their
physical location in the local area network 14. For example, a unique name
will be stored in the name service program 19 on the name server system 18
to allow individual users 10a-10c to execute a unique application on an
application server system 16.
In the name server system 18, each individual user 10a-10c will have a
personal account, and one or more "special" accounts; each account,
whether personal or special, has a respective account identification to
enable each individual user 10a-10c to log on to the computer system 10 to
use a particular application identified in the name server system 18. Each
"special account" corresponds to a specific job function, e.g.,
organizational role. An individual user logged in under such a specialized
account is able to perform those applications particular to the
corresponding job function.
Referring now to FIG. 2, an applicant 100 supplies biometric information
105 to a registrar 110 as part of the processing of an account. All
accounts in the computer system 10 are administered by the account
registrar 110, an entity having its own identity, with responsibility for
account administration for some enterprise. During the production or
modification of an account, the registrar 110 captures an applicant's
biometric information 105. The system uses a public key encryption
technology for authentication to provide authentication data. The
authentication data will be associated with the account for use in login
authentication and will be the public key of a public key/private key
pair.
The registrar 110 causes a new public/private key pair to be generated. The
private key is issued to the user (typically in the form of stored
information in some device 115 such as a passcard) while the public key
for the account is stored along with other account information in a
so-called "certificate" for that account. The biometric data 105 supplied
by the applicant 100 is preferably integrity locked into the certificate
along with the authentication data (e.g. user's public key) and other
security-critical information which may be needed by the system (e.g.,
such as the user's authorized role).
The integrity-locked digitized canonical biometric data is hereinafter
referred to as "certificate-based alias detection data (CBAD)." The
registrar integrity locks the certificate by appending a digital signature
to it. A digital signature in its simplest form is simply an encrypted
copy of the certificate that is encrypted using the registrar's assigned
private key (which is known only to the registrar 110 and the registrar's
work station). The digital signature is used with the data to be
"integrity-locked" by using the signature to provide an encryptographic
checksum or other appropriate code. Appending the digital signature
provides "integrity-locked" or digitally signed
account/authentication/certificate-based alias detection data 120 where it
is stored in the name service program 19. The above mentioned public key
cryptographic type techniques are used to ensure that tampering of
account/authentication/certificate-based alias detection data is
detectable.
At a later time, any entity may verify that the account certificate 130
was, indeed, signed by the registrar 110 by decrypting the digital
signature using the registrar's 110 public key (which is known throughout
the system) and comparing the results with an associated plaintext
certificate of the decrypted digital signature. The plaintext certificate
is a decrypted version of the digital signature. If they are identical,
the entity using the account certificate is confident that neither the
plaintext nor encrypted versions of the account certificate were modified
after they were created or modified by the registrar 110, and that the
account certificate data did originate from the registrar's workstation.
When an individual user logs on to a workstation, the individual user
provides information (such as the user's name) that is used by the local
operating system to locate and fetch an account certificate from the name
service program 19 as the first step in authenticating, or confirming the
identity, of the individual user. The local operating system then
validates the account certificate's digital signature using the
registrar's public key. If the account certificate is valid, the public
key assigned to that account by the registrar 110 is known.
The individual user trying to log in then presents a digitally signed
"login delegation certificate" to the workstation. A login delegation
certificate is what the user sends to the local operating system to be
authenticated. (Typically, this would be done by a smartcard issued to the
individual user by the registrar 110, containing the individual user's
personal private key.) The operating system validates the login delegation
certificate by decrypting it using the public key it obtained from the
account certificate. If the validation is successful, the operating system
knows that the public key obtained from the account certificate matches
the private key in the possession of the individual user trying to log on,
and is justified in assigning to that individual user any rights or
privileges associated with the account. At no time during the
authentication process is the CBAD data in the account certificate used.
Since CBAD data does not determine the success or failure of a login
authentication, there is no compromise to the integrity of the login
authentication system if CBAD data is public.
In order to invoke a remote application (e.g., from the application server
system 16) to be executed on behalf of, or at the request of, a properly
authenticated local user, the workstation operating system generates a
so-called remote delegation certificate for the request by appending to
the request the individual user's login delegation certificate and
digitally signing it using the workstation's private key. A remote
delegation certificate is what the local computer operating system sends
to the applications server system 15 to obtain services on behalf of the
individual user. The application server system 16 can then verify that the
remote delegation certificate came from the workstation (by applying the
workstations public key to the signature), and, if this is successful, can
reauthenticate the identity of the individual user by verifying the user's
signature on the included remote delegation certificate using the user's
assigned public key. Provided that both of these tests are successful, the
application server system 16 knows that the included request emanated from
the workstation claimed, acting on behalf of the user account claimed,
and/or can use this information to determine whether or not the request
should be honored. Since CBAD-data is not used to determine the validity
of a remote delegation certificate, there is no compromise to the remote
request authentication system if CBAD data is public.
Each user also has an associated account certificate 130. A user
certificate 130 is a data structure, generated by the operating system,
that includes user information 120 and CBAD data, if it exists , which are
bound together. The binding of these data can be provided by using a
cryptographic checksum. The checksum ensures that any corruption of the
user information 120 is detectable by the system. The encryption uses the
registrar's 110 private key or encryption code, thus generating a digital
signature that uniquely identifies the source of the account information
as the registrar 110. The account certificate 130 is then posted by the
operating system to the name service system 135. Thus, execution of
selected tasks can be restricted to selected users or groups of users.
During user logon the computer system 10 collects user certificate
information 130, as mentioned above to produce a validation credential for
the particular user. Such validation credentials are used by the computer
system 10 to identify each user and to determine whether the identified
user has the necessary privileges to execute a particular application. At
this juncture the computer system 10 is using the account certificate
information 130 to produce a validation credential if the particular user
has been authorized to execute the particular identified transaction.
Thus, to produce validation credentials, to determine which users may
access certain computer applications, individual
account/authentication/certificate-based alias detection data is collected
by the registrar 110. Such information includes both the conventional user
information such as the user's name, mentioned above, authentication data
assigned to, or obtained from, the user, and digitized canonical biometric
data (BioM), here referred to as Certificate-Based Alias Detection Data
(CBAD), as mentioned above. The system may include accounts which include
CBAD data and accounts which do not include CBAD data. The effect of the
presence or absence of CBAD data will be described below.
Although an alias detection system to be described below is here discussed
in the context of a single computer system, it should be understood that
this alias detection can be implemented on a multi-computer system joined
together via large computer networks, such as wide area networks. This
allows computer users located throughout the large computer network to
execute a common application.
As illustrated in FIG. 2, the CBAD data is captured as part of the account
operation and stored for later use when a separation of duties policy
needs to be enforced (as will be fully described below). Here, it is used
for determining user distinctness and detecting alias accounts. This use
permits the enforcement of a separation of duties policy that is resistant
to attacks by unscrupulous users who assume multiple everyday identities.
It also allows for enforcement of separation of duties policy even with
systems using lax administration that do not minimize the number of
accounts granted to an individual user. It also facilitates creating
separate accounts for individuals for specialized purposes. Such
approaches resist privilege accumulation, since users log in only with
specific sets of privileges, rather than with the accumulated total of all
possible privileges which they are permitted to exercise.
Referring now to FIG. 3, the steps involved in certificate-based alias
detection which is invoked when a particular unit of processing executes
on behalf of more than one user are shown. Certificate based alias
detection is provided in the operating platform (e.g., operating system,
transaction monitor) of the computer system 10 in FIG. 1.
The computer system 10 produces a validation credential for the associated
user from the account certificate. As previously mentioned, a validation
credential is an integrity-sealed (i.e., digitally signed) packet that
logically bound together the identity of an authenticated user, a request
made on behalf of that user, and the CBAD data, if any, for the user. An
authenticated user is a user having predetermined authorization to execute
the particular application. The predetermined authorization is granted to
the user by a system manager or registrar who has the necessary privileges
to do so. Binding of the integrity-sealed packet is provided by the
operating system appending the user information with the application
transaction. Prior to executing the unit of processing, however, the
security policy for that unit of processing is examined. If necessary to
protect security, certificate based alias detection is triggered by an
appropriate statement in the security policy (38 in FIG. 4) for the
specific application transaction which the user chooses to execute.
The general manner in which user data and alias detection data may be used
in a data processing system in the context of the present invention will
now be explained. It will be assumed that the transaction to be described,
by way of example, requires an application initiation request and an
application approval entry to be inputted into the system by different
permitted users.
As shown in FIG. 3, the transaction is initiated at step 158 when an
individual user who has logged on to the system, and submits a data
processing application initiation request. A review or an approval entry
then is submitted at step 158 before further processing of the transaction
can proceed.
At step 160 the digital signature on the delegation certificate for the
user initiation request and the digital signature on the delegation
certificate for | | |
