Network Security

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Network Security Kerberos
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INTRODUCTION

• Kerberos is a network authentication protocol. It
  is designed to provide strong authentication for
  client/server applications by using secret-key
  cryptography.
• Authentication is the process of verifying
  whether the client is genuine or not. It is
  widely used in Internet to prevent corruption of
  files and to provide safe networking

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encrypted database.
The Kerberos keeps a database of its clients
and their private keys. The private key is a
large number known only to Kerberos and the
client it belongs to. In the case that the client
is a user, it is an encrypted password.

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FOCUS IN DEPTH

• KERBEROS
• Kerberos is a trusted third-party authentication
  service. It is trusted in the sense that each of
  its clients believes Kerberos judgment as to the
  identity of each of its other clients to be
  accurate.
• Timestamps have been added to make the
  authentication and detection of replay.
• Replay is something that occurs when a message is
  stolen from the network and resent later.

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CREDENTIALS

• There are two types of credentials used in the
  Kerberos authentication model tickets and
  authenticators.
• The ticket is used to securely pass the identity
  of the person to the end server.
• When single server and single client are
  involved, the ticket contains the name of the
  server, the name of the client, the internet
  address of the client, timestamp, lifetime and a
  random session key.
• This information is actually encrypted using the
  key of the server. After the ticket is issued,
  the client may use it many times to gain access
  to the server until the ticket is expired.
• The ticket is actually encrypted by the end
  server.
• So it is safe for the client to pass it on to the
  server

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KERBEROS SOFTWARE COMPONENTS

• DATA ENCRYPTION AND DECRYPTION
• In Kerberos the encryption is based on the Data
  Encryption Standard (DES).
• Several encryption methods are provided with
  balance between speed and security.
• It is responsible to change the data to cipher
  text and is an independent module

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DATABASE MANAGEMENT SYSTEM

• WS Work station
• It has a record for each principal containing the
  name, private key, expiration date of the
  principal and additional information for that
  principal.
• Sensitive information like passwords should be
  handled carefully using high security measures.

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ADMINISTRATIVE DATABASE This takes care of the
administrative requests from the user. The user
may wish to change his password. Or there may be
a new principal. This cannot be done in slave
machines. This will be done in the administrative
module maintained by the master.
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THE WORKING OF KERBEROS

• Kerberos maintains a database of its clients and
  their corresponding private key. The private key
  is known only to the Kerberos and the client.
• If the client is a user then the private key will
  be an encrypted password.
• Since the private key is known only to the
  Kerberos, it convinces its clients that the
  message is truly from the other

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• Authentication on the sender.
• Authentication for all incoming messages.
• Creating private message
• i.e., encrypting the message.

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APPLICATION OF KERBEROS IN WINDOWS 2000

• Windows 2000 will have a Kerberos client
  installed with extensions that permit initial
  authentication using public key certificates.
• The windows 2000 implementation of Kerberos (MIT
  KERBEROS V5) encryption based on RC-4 algorithm
  and using a MD5 HMAC.
• This is of 128 bit key length and provides an
  alternative to the existing DES (Data Encryption
  Standard) based encryption

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OUR VIEW ON ENHANCING KERBEROS

• The conversion of the data to cipher text
  involves data encryption module.
• We presume that the conversion should follow
  different and complicated techniques thereby
  making it difficult for the hackers to work on
  it.
• The password generated should be highly random
  and non-sequential.
• So that it is highly securitized.

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CONCLUSION

• Network security is a vast ocean and only a drop
  of it has been dealt with. Security is not a
  static thing it is a continually evolving
  process.
• To obtain true security, constant vigilance is to
  be maintained. Kerberos can keep network
  resources from being exploited by hackers.
• Kerberos represents a big advance in network
  authentication techniques, and continues to be
  the most widely used single-sign on system. .
  Passwords remain the Achilles heal for Kerberos
  users.

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