Introduction
X.800 – OSI Security Services
• Security Service – a service provided by a
protocol layer of communicating open systems,
which ensures adequate security of the systems or
of data transfers
• RFC 2828 – a processing or communication
service that is provided by a system to give a
specific kind of protection to system resources;
security services implement security policies and
are implemented by security mechanisms.
Security Services
• Authentication – assurance that the communicating entity is who they
say they are
• Access Control – prevent the unauthorized access to some system
resource
– Who can access
– Under what conditions
– What they are allowed to do
• Data Confidentiality – protection of data from unauthorized disclosure
• Data Integrity – insure that data received is exactely what was sent
• Nonrepudiation – protection from denial by one of the entities
involved in a communication of having participated in all or part of the
communication
Authentication
• Peer Entity Authentication – in a connection based
environment; provide confidence in the identity of a
connecting entity
– Logging in with a password
– Gaining access via biological identity verification
• DNA identification, retinal scan, finger/hand print identification
– Access via audio voice identification
• Data Origin Authentication – in a connectionless
environment; provide assurance that the source of received
data is as claimed
– Corroborates the source of the data
– Does not proved assurance against duplicate or modified data
Access Control
• This service provides protection against unauthorized use
of resources accessible via OSI. These may be OSI or nonOSI resources accessed via OSI protocols. This protection
service may be applied to various types of access to a
resource or to all accesses to a resource
– e.g., the use of a communications resource; the reading, the
writing, or the deletion of an information resource; the execution
of a processing resource
Data Confidentiality
• Connection Confidentiality
– Protection of all user data on a connection
• Connectionless Confidentiality
– Protection of all data within a single data block
• Selective-Field Confidentiality
– Insure confidentiality of selected fields with within the user data on
a connection or in a single data block connection
• Traffic-Flow Confidentiality
– Protection of information that might be derived by observing the
traffic flow patterns
Data Integrity
• Connection Integrity with Recovery
– Detect any modification of stream data or replay of data and retry;
• Connection Integrity without Recovery
– Detect any modification and report it, no retry…continue on
• Selective-Field Connection Integrity
– Same except for selected fields
• Connectionless Integrity
– Detect modifications in fixed block connectionless data, may provide
replay detection and protection
• Selective-Field Connectionless Integrity
– Same, except for selected fields
• Total stream protection would encompass all of the above and is
probably the best strategy
Nonrepudiation
• Nonrepudiation, Origin
– Proof that the message was sent by the specified party
• Nonrepudiation, Destination
– Proof that the message was received by the specified party
Security Mechanisms (X.800)
•
•
•
•
•
•
•
Encipherment – algorithmic/mathematical conversion
Digital Signature – appending a secret signature
Access Control Access Control
Data Integrity
Authentication Exchange
Traffic Padding – appending extra chars to foil traffic analysis
techniques
• Routing Control – selection of secure routeds through the network
• Notarization – use a trused 3rd party (like a notary public)
Other Security Mechanisms
(non X.800)
• Trusted Functionality
– That which is perceived to be true by some criteria (policy)
• Security Label
– The marking of (bound to) a resource that names or desiginates the
security attributes of the resource
• Event Detection
– Intrusion detection
– Detection of specific hacks (detector hardware)
– Too many log in attempts
• Security Audit Trail
– Logging of all system events
• Security Recovery
– Recovery based on requests from security mechanisms and/or event
handling.
Network Security Model
Trusted 3rd Party
M
F(s)
M’
Info Channel
M’
s
F(s)
s
Opponent
F(s)-some function that mutates M into M’ based on s
F(s) – some function that reverses the mutation of M’ back into M
M
Internet Organizations
• Internet Architecture Board (IAB) – responsible for the
overall design of the Internet, provides guidance to IETF
• Internet Engineering Task Force (IETF) – protocol
engineering and development of the Internet
– Working groups chartered by IETF do actual development work
• Internet Draft, RFC, Standard
• 8 areas – General, Applications, Internet, Operations and
management, Routing, Security, Transport, User Services
– IETF responsible for actual publishing
• Internet Engineering Steering Group (IESG) – responsible
for technical management if IETF activities and the
Internet Standards process
RFC Publication Process
Internet Draft
Proposed
Standard
Best Current
Practice
Experimental
Draft
Standard
Internet
Standard
Historic
Informational