[ Computer Network ]
[ Unit 6 ]
[ Network Security ]
Computer network security consists of measures taken by business or some
organizations to monitor and prevent unauthorized access from the outside
attackers.
Different approaches to computer network security management have different
requirements depending on the size of the computer network. For example, a home
office requires basic network security while large businesses require high
maintenance to prevent the network from malicious attacks.
Network Administrator controls access to the data and software on the network.
A network administrator assigns the user ID and password to the authorized
person.
Aspects of Network Security:
Following are the desirable properties to achieve secure communication:
,o Privacy:
Privacy means both the sender and the receiver expects
confidentiality. The transmitted message should be sent only to the
intended receiver while the message should be opaque for other users. Only
the sender and receiver should be able to understand the transmitted
message as eavesdroppers can intercept the message. Therefore, there is a
requirement to encrypt the message so that the message cannot be
intercepted. This aspect of confidentiality is commonly used to achieve
secure communication.
o Message Integrity:
Data integrity means that the data must arrive at the receiver
exactly as it was sent. There must be no changes in the data content during
transmission, either maliciously or accident, in a transit. As there are more
and more monetary exchanges over the internet, data integrity is more
crucial. The data integrity must be preserved for secure communication.
o End-point authentication:
Authentication means that the receiver is sure of the sender?s
identity, i.e., no imposter has sent the message.
o Non-Repudiation:
Non-Repudiation means that the receiver must be able to prove that
the received message has come from a specific sender. The sender must not
deny sending a message that he or she send. The burden of proving the
identity comes on the receiver. For example, if a customer sends a request
to transfer the money from one account to another account, then the bank
must have a proof that the customer has requested for the transaction.
, [ Privacy ]
The concept of how to achieve privacy has not been changed for thousands of
years: the message cannot be encrypted. The message must be rendered as opaque
to all the unauthorized parties. A good encryption/decryption technique is used to
achieve privacy to some extent. This technique ensures that the eavesdropper
cannot understand the contents of the message.
Encryption/Decryption
Encryption: Encryption means that the sender converts the original information
into another form and sends the unintelligible message over the network.
Decryption: Decryption reverses the Encryption process in order to transform the
message back to the original form.
The data which is to be encrypted at the sender site is known as plaintext, and the
encrypted data is known as ciphertext. The data is decrypted at the receiver site.
There are two types of Encryption/Decryption techniques:
o Privacy with secret key Encryption/Decryption
o Privacy with public key Encryption/Decryption
[ Unit 6 ]
[ Network Security ]
Computer network security consists of measures taken by business or some
organizations to monitor and prevent unauthorized access from the outside
attackers.
Different approaches to computer network security management have different
requirements depending on the size of the computer network. For example, a home
office requires basic network security while large businesses require high
maintenance to prevent the network from malicious attacks.
Network Administrator controls access to the data and software on the network.
A network administrator assigns the user ID and password to the authorized
person.
Aspects of Network Security:
Following are the desirable properties to achieve secure communication:
,o Privacy:
Privacy means both the sender and the receiver expects
confidentiality. The transmitted message should be sent only to the
intended receiver while the message should be opaque for other users. Only
the sender and receiver should be able to understand the transmitted
message as eavesdroppers can intercept the message. Therefore, there is a
requirement to encrypt the message so that the message cannot be
intercepted. This aspect of confidentiality is commonly used to achieve
secure communication.
o Message Integrity:
Data integrity means that the data must arrive at the receiver
exactly as it was sent. There must be no changes in the data content during
transmission, either maliciously or accident, in a transit. As there are more
and more monetary exchanges over the internet, data integrity is more
crucial. The data integrity must be preserved for secure communication.
o End-point authentication:
Authentication means that the receiver is sure of the sender?s
identity, i.e., no imposter has sent the message.
o Non-Repudiation:
Non-Repudiation means that the receiver must be able to prove that
the received message has come from a specific sender. The sender must not
deny sending a message that he or she send. The burden of proving the
identity comes on the receiver. For example, if a customer sends a request
to transfer the money from one account to another account, then the bank
must have a proof that the customer has requested for the transaction.
, [ Privacy ]
The concept of how to achieve privacy has not been changed for thousands of
years: the message cannot be encrypted. The message must be rendered as opaque
to all the unauthorized parties. A good encryption/decryption technique is used to
achieve privacy to some extent. This technique ensures that the eavesdropper
cannot understand the contents of the message.
Encryption/Decryption
Encryption: Encryption means that the sender converts the original information
into another form and sends the unintelligible message over the network.
Decryption: Decryption reverses the Encryption process in order to transform the
message back to the original form.
The data which is to be encrypted at the sender site is known as plaintext, and the
encrypted data is known as ciphertext. The data is decrypted at the receiver site.
There are two types of Encryption/Decryption techniques:
o Privacy with secret key Encryption/Decryption
o Privacy with public key Encryption/Decryption
