encryption scheme usually uses
a pseudo-random encryption
key generated by an algorithm. Information or message, called plaintext,
is encrypted using an encryption algorithm, a cipher used to generate cipher
text that can only be read if decrypted.
The different types of encryption: DES, Triple
DES, RSA, Blowfish, Twofish and AES.
Hash values are used to identify secret
information. It is very hard to find data that will generate the same hash value. Hash functions are
categorized into cryptographic hash functions
and provably secure hash functions.
Cryptography is a computational procedure that takes
variable inputs, including a cryptographic key, and produces an output. When
using an asymmetric or public key in cryptography the need of exchanging keys
is not necessary, therefore the key distribution problem is eliminated. The
Public key cryptography increase the security level and the private keys do not
need to be transmitted or revealed to anyone. Also asymmetric provides digital
signatures that can be repudiated
Advantages of having symmetric cryptosystem are that
they are faster, encrypted data can be transferred on the link even if there is
a possibility that the data will be intercepted, symmetric keys use password
authentication to prove the receiver’s identity, and also use a system only
which possesses the secret key can decrypt a message. But symmetric keys have a
problem of key transportation. Symmetric keys do not provide digital signatures
that cannot be repudiated.
The most common types of attacks:
viruses, malwares, spywares and Trojan horses. Intrusion to database or
accessing Internet without permission.
Data capturing and cryptanalysis: the confidential data is
captured or stolen from the channels and cryptanalysis is performed on it to
extract the original data.
Unauthorized Installing of Applications: installing
unauthorized or uncertified applications within the system leads to virus
intrusion and security breaching.
Unauthorized Access: intrusion of any unauthorized person
within the network resources or in data records leads to loss of confidential
Virus Infection: network or resources are
attacked with viruses