http://www.grid-support.ac.uk
http://www.ngs.ac.uk
Security on Grids
The Grid Security Infrastructure
Guy Warner
NeSC Training Team
http://www.nesc.ac.uk/
http://www.pparc.ac.uk/
http://www.eu-egee.org/
Acknowledgements
Some of the slides in this presentation are based on / motivated by:
• The presentation given by Carl Kesselman at the GGF Summer
School 2004. This presentation may be found at
– http://www.dma.unina.it/~murli/GridSummerSchool2004/
curriculum.htm
• Lectures given by Richard Sinott and John Watt at the University of
Glasgow. These lectures may be found at
– http://csperkins.org/teaching/2004-2005/gc5/
• The presentation given by Simone Campana of CERN at First
Latinamerican Grid Workshop, Merida, Venezuela. This presentation
may be found at
– http://agenda.cern.ch/fullAgenda.php?ida=a044965
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The Problem
User
Resource
• Question:
How does a user securely access the Resource without having an
account on the machines in between or even on the Resource?
• Question:
How does the Resource know who a user is and that they are
allowed access?
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Overview
Security
Authentication
Grid Security
Infrastructure
Encryption &
Authorization
Data Integrity
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Approaches to Security: 1
The Poor Security House
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Approaches to Security: 2
The Paranoid Security House
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Approaches to Security: 3
The Realistic Security House
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Approaches to Grid
Security
• The Poor Security Approach:
– Use unencrypted communications.
– No or poor (easily guessed) identification means.
– Private identification (key) left in publicly available location.
• The Paranoid Security Approach:
– Don’t use any communications (no network at all).
– Don’t leave computer unattended.
• The Realistic Security Approach:
– Encrypt all sensitive communications
– Use difficult to break identification means.
– Keep identification secure at all times (e.g. encrypted on a
memory stick).
– Only allow access to trusted users.
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The Risks of Poor User
Security
• Launch attacks to other sites
– Large distributed farms of machines, perfect for launching a
Distributed Denial of Service attack.
• Illegal or inappropriate data distribution and
access sensitive information
– Massive distributed storage capacity ideal for example, for
swapping movies.
• Damage caused by viruses, worms etc.
– Highly connected infrastructure means worms spread faster than
on the internet in general.
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Authentication and
Authorization
0598234
John
Jane Doe
755 E. Woodlawn
Urbana IL 61801
• Authentication
– Are you who you claim to be?
• Authorisation
– Do you have access to the resource you are connecting to?
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The Trust Model
No Cross-
Domain Trust
Certification
Authority
Certification
Authority
Policy
Authority
Policy
Authority
Sub-Domain B1
Sub-Domain A1
Domain A
Domain B
Task
Federation
Service
GSI
Server X
Virtual
Organization
Domain
Server Y
slide based on presentation given by Carl Kesselman at GGF Summer School 2004
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Public Private Key
Bob
Alice
SECURE
SECURE
INSECURE
Life Savings
Life Savings
Life Savings
Private Key
Message
Public Key
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Certificates
• Similar to passport or driver’s license:
Identity signed by a trusted party
Name
Issuer
Public Key
Signature
John Doe
755 E. Woodlawn
Urbana IL 61801
State of
Illinois
Seal
BD 08-06-35
Male 6’0” 200lbs
GRN Eyes
slide based on presentation given by Carl Kesselman at GGF Summer School 2004
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Certificate Authorities
• A small set of trusted entities
known as Certificate Authorities
(CAs) are established to sign
certificates
• A Certificate Authority is an entity
that exists only to sign user
certificates
• Users authenticate themselves to
CA, for example by use of their
Passport or Identity Card.
• The CA signs it’s own certificate
which is distributed in a secure
manner.
Name: CA
Issuer: CA
CA’s Public Key
CA’s Signature
slide based on presentation given by Carl Kesselman at GGF Summer School 2004
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Delegation and Certificates
Delegation : The act of giving an organization, person or service the right
to act on your behalf.
• For example: A user delegates their authentication to a service to allow
programs to run on remote sites.
User
CA
Proxy
Service
Signs
own
Certificate
signs
Certificate
signs
Certificate
Stage1:
Stage2:
Stage3:
Low
Frequency
Medium
Frequency
High
Frequency
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User Authorisation to
Access Resource
slide based on presentation given by Carl Kesselman at GGF Summer School 2004
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User Responsibilities
• Keep your private key secure.
• Do not loan your certificate to anyone.
• Report to your local/regional contact if your
certificate has been compromised.
• Do not launch a delegation service for longer than
your current task needs.
If your certificate or delegated service is
used by someone other than you, it
cannot be proven that it was not you.
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Summary
User
via Certificates and
Delegated Services
delegated to VO.
Authentication
Authorisation
Resource
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