GRID Security Review - Computer Network Security - page 107

object. Each copy of the local object stores all or part of the DSO's state (in the Se-
mantics sub-object) and is called a replica object . Sometimes a replica object does not
store the DSO's state at all but simply forwards the user requests to replicas that can
execute them in which case it is called a user proxy .
Each user or programmer in a local system interacts with the DSO in the same way
as if the original local object was stored in the local system. Separate sub objects of
local objects control replication of local objects and communication between them,
while the semantics sub object implements the main functionality of the local objects.
The DSO notion is important as it gives the Globe objects the ability to be shared
amongst different systems that form a wide area network in excess of their normal
ability to be shared amongst the users of the same system [10].
3.4.2 Proposed Security Architecture
During the initial development phase of the Globe Security Architecture, security
issues concerning wide-area distributed systems were categorized in three major
groups [11]:
- Secure binding . Verification of the local and replica objects being part of a certain
DSO and association of the DSO to real world entities.
- Platform security . Protection of hosts from malicious mobile code and protection of
mobile code from malicious hosts.
- Secure method invocation . User authentication and access control, communications
protection and reverse access control (verification of replica objects trustworthi-
ness).
The Globe Security Architecture is based on public key cryptography and digital
certificates in order to address the above issues. In detail, DSOs, replicas and users are
assigned public/private key pairs in order to be identified and are granted permissions
through the use of the above-mentioned certificates. Next, we present the means
through which Globe security architecture addresses the above mentioned issues [11].
3.4.2.1 Secure Binding
As mentioned above, secure binding is concerned with securely associating a DSO to
its public key, a replica to corresponding DSO and a DSO to corresponding real world
entity. Secure association of a DSO to its public key is achieved through public key
integration with the OID. The second issue is addressed by looking at the OID, at the
replica certificate and its administrative certificate chain. Finally, the individual cli-
ents are responsible to establish a secure name binding for the DSOs they are using
although external trust authorities could mediate this.
3.4.2.2 Platform Security
Platform security is concerned with the protection of hosts from malicious mobile
code and the protection of mobile code from malicious hosts. The former issue is
addressed with the use of the java “sand boxing” technique in combination with code
signing while the later is addressed with the use of the reverse access control mecha-
nism or state signing.