Network Security Basic Concept
NETWORK SECURITY
Terminology
P = Plaintext = Maintext = Message = Readable
C = Cryptictext = Ciphertext = Unreadable format
E = Encryptionn== Enciphermen
D = Decryption = Decipherment
Cryptography
This means secret writing
Modes of Cryptography
Public Key Cryptography
Public key is used for encryption and is known to all.
Private key is used decryption and it is kept secret.
By looking at the public key,one cannot guess the private key.
Key generation:
(i) n = p * q and z = ( p - 1)(q - 1)
(ii) GCD ( z, d) = 1
(iii) ( e * d ) mod z = 1
RSA Algorithm
Public key is a pair of numbers ( N, e) and similarly Private key is a pair of numbers (N, d), then relation between these two pairs is given as
Terminology
P = Plaintext = Maintext = Message = Readable
C = Cryptictext = Ciphertext = Unreadable format
E = Encryptionn== Enciphermen
D = Decryption = Decipherment
Cryptography
This means secret writing
Modes of Cryptography
Public Key Cryptography
Public key is used for encryption and is known to all.
Private key is used decryption and it is kept secret.
By looking at the public key,one cannot guess the private key.
Key generation:
(i) n = p * q and z = ( p - 1)(q - 1)
(ii) GCD ( z, d) = 1
(iii) ( e * d ) mod z = 1
RSA Algorithm
Public key is a pair of numbers ( N, e) and similarly Private key is a pair of numbers (N, d), then relation between these two pairs is given as
C = Pe Mod N
P = Cd Mod N
Digital Signature (DS)
Excluding first parameter all the remaining network security parameters are achieved through digital signature.
Approaches in DS are:
(i) Signing the whole document: used for large transaction
(ii) Signing the digest of the document:
(a) Used for transaction which last for a shoter period
(b) Digest is the compressed form a specific part of the whole document
(c) Hashing is the method which is used to generate a digest from a document.
In DS , E and D technique are deployed with hashing process.
From digest message can't be generated.
If network security is to be attained , consider the following:
(i) Privacy
(ii) Authentication
(iii) Integrity
(iv) Non-repudiation
Firewall
Basically a firewall can be a machine (server) or a router configured as a firewall. This is used to control access (permit/deny) our network from the outside network.
Firewall can permit or deny a host/subnet/network services/websites.
Type of Firewall:
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