Any message written over a fixed set of symbols can be represented as a binary string (a sequence of 0's and 1's)
Binary digits 0 and 1 are called bits
To reduce computation overhead, encryption algorithms should only use operations that are easy to implement
For a binary string X:
The length of X, denoted by |X|, is the number of bits in X
If |X| = l, X is an l-bit binary string
Let a be a binary bit and k a non-negative integer. Denote by ak a binary string consisting of k copies of a
Denote the concatenation of X and Y by XY or...
Encryption is the process of protecting data by using an algorithm to scramble it. The
data is unintelligible, undetectable, unreadable and irretrievable unless a key is used
to reverse the encryption, or decrypt, the data.
Encryption is used all the time, often without you even realising it. Whenever you buy
something online and make a transaction, all your details are heavily encrypted until
they reach the other end, making sure that no third party could be listening in.
If a company’sWeb site is used to collect, compile, or process customer data, that company has an added point of vulnerability. The increased
vulnerability in this situation arises from the potential of a hacker breaking into the Web site and stealing data such as names, address,
account information, or credit card numbers. In addition, if the Web site is integrated with back-end applications or connected to other
systems in the enterprise, there is a greater possibility that hackers and information thieves can access more sensitive information that
otherwise may be kept private.
To use data encryption algorithms in network communications, all parities must first agree on using the same secret keys
Rely on couriers
Set up a meeting to determine a secret key
Use postal service, email service, phone service
However, these conventional methods are inflexible for network communication applications
Public-key cryptography (PKC)
Invented in the 1970’s
Without the need of sharing prior secrets to distribute secret keys securely
Can also be used for authentication
What Is Needed to Build a VPN? Overlay and Peer-to-Peer VPN Architecture VPN Topologies Characteristics of a Secure VPNs VPN Security: Encapsulation VPN Security: IPsec and GRE VPN Security: Symmetric and Asymmetric Encryption Algorithms Symmetric Encryption Algorithms Asymetric Encryption Diffie-Hellman Key Exchange Data Integrity VPN Security: Authentication
E-commerce Security Issues CHAPTER 13
your encrypted messages. As shown in Figure 13.4, both the sender (who encrypts the message) and the recipient (who decrypts the message) have the same key. The most widely used secret key algorithm is the Data Encryption Standard (DES). This scheme was developed by IBM in the 1970s and adopted as the American standard for commercial and unclassified government communications. Computing speeds are orders of magnitudes faster now than in 1970, and DES has been obsolete since at least 1998.
Radio based communication, open air
The attacker, having a radio transmitter and receiver with the same radio frequency of the underlying wireless network, can easily:
Intercept wireless data
Connect his computing devices to a nearby wireless network
Inject new packets to an existing wireless network
Jam a particular wireless channel using a jamming device
Implement encryption algorithms, authentication algorithms, and integrity-check algorithms at the data-link layer
Provide network access with wired equivalent privacy
Higher-layer protocols and applications can be used ...
IPSec—IP Security Protocol. IPSec is a framework of open standards that provides data
confidentiality, data integrity, and data authentication between participating peers. IPSec provides
these security services at the IP layer; it uses IKE to handle negotiation of protocols and algorithms
based on local policy and to generate the encryption and authentication keys to be used by IPSec.
IPSec can be used to protect one or more data flows between a pair of hosts, between a pair of
security gateways, or between a security gateway and a host....
Grid computing architecture was defined to be a complete physical layer. Based on the grid computing architecture, we divided grid nodes into supervisor grid node and execute grid nod. The data transfer in network must be in secure. In this study, we propose the encryption and decryption algorithm in each grid node to keep information processing in security. We create user information database both in supervisor and execute grid nodes. We use them to verify user processing in system.