Wireless, and Security
Spring 2017
Circuit Switching: A form of data communication which establishes a single connection or circuit between source and destination to carry the data stream.
Like a conventional telephone system.
Packet Switching: A form of data communications which breaks a data stream into small sections, sends them separately by the best available channels and reassembles the original data stream at its destination.
An alternative is to allocate the capacity to the traffic only when it is needed, and share the available capacity between many users.
A wireless access point is a device that connects wireless devices (laptops, etc.) to a wired network, usually an Ethernet LAN.
Wireless Settings:
SSID (Service Set Identifier) – Name of your network
Security: WPA2, WPA, WEP, or none
The following information is from my own research and experience.
Wireless Frequency
Wireless APs operate at:
– 2.4 GHz
– 5 GHz
2 GHZ! That’s the same as my microwave oven, isn’t that dangerous?
Answer: No.
– Electromagnetic waves happen naturally.
• Light is an electromagnetic wave
– It is not the frequency, but the wattage, the power.
• Any electromagnetic wave can be dangerous with too much power.
• A 25 watt light bulb is safe, but it wouldn’t be safe at 250,000 watts
– Wireless access points generate signals at 1/10th of a watt.
• Like all electromagnetic waves, the signal does not fade in a linear manner, but inversely as the square of the distance.
Inverse square law
Double the distance of the wireless link, we receive only ¼ of the original power.
Triple the distance of the wireless link, we receive only 1/9 the original power.
Move 5 times the distance, signal decreases by 1/25.
Putting it in some perspective
Measurements from an antenna transmitting 100mW at 1 inch
Remember a milliwatt is 1/1,000th of a Watt
Microwave oven typically operates at 1,000 watts in a confined space.
1” 100 mW 1/10th watt
2” 25 mW 1/40th watt
4” 6.25 mW 1/166th watt
8” 1.56 mW 1/1000th watt
16” 0.39 mW 4/10,000th watt
32” 0.097 mW 1/10,000th watt
64” (5.3 ft) 0.024 mW 2/100,000th watt
128” (10.6 ft) 0.006 mW 6/1,000,000th watt
256” (21.3 ft) 0.0015 mW 1 5/10,000,000th watt
Light bulbs would also be dangerous the were 10,000 to 1,000,000,000,000
Wireless Security
As long as our wireless computer and access point are using the same encryption algorithm, such as WPA2.
Make your Pre-Shared Key over 25 characters long and make it random
Cryptology
· From the Greek kryptós, "hidden," and lógos, "word“
· Is the science of secure (or, generally speaking), secret communication
Cryptography
· The branch of applied mathematics that concerns itself with transforming messages into seemingly unintelligible forms and back again so it cannot be viewed by unauthorized users
· Cryptography is the process of converting plaintext into ciphertext (unreadable text) by using an encoding function, such as an encryption algorithm or a secret list of substitution characters
Benefits of Cryptography
Protections provided:
Confidentiality
Authentication
Integrity
Authentication
· Verify the sender
· Trust the sender is whom they claim to be
· Ensures that a message:
– comes from an authentic source and
– goes to an authentic destination
Characteristics of a Secure VPNs
Data confidentiality
Allows only authorized users to access the Information
Protecting data from eavesdroppers
Aims at protecting the message contents from being intercepted by unauthenticated or unauthorized sources.
Characteristics of a Secure VPNs
Data integrity
Trust the information has not been altered
Across the Internet, there is always the possibility that the data has been modified.
Data integrity guarantees that between the source and destination:
– No tampering or alternation to data
– digital signatures
Encryption: changing the original text to a secret message using cryptography
Decryption: reverse process of encryption
Algorithm: mathematical procedure that works with a key to generate ciphertext from plaintext input
AKA cipher
Key: is a mathematical value (e.g., word, number, phrase) that determines how a plaintext message is encrypted to produce ciphertext
· Its possession is required to decrypt the ciphertext and recover the original message
· Key Length: keys have a corresponding key length (or key size): which is the number of bits, or sometimes bytes, in the key
· Key lengths tend to be huge numbers a 2-bit key has 4 values in its key space (00, 01, 10, 11)
· Generally, the larger the key length, the more secure the ciphertext
HTTPS - Look for the lock
Publishers willingly allow pop-ups or pop-unders because they command higher prices, and they're in high demand by advertisers.
Spyware is computer software that gathers and reports information about a computer user without the user's knowledge or consent.
May perform many different functions, including:
– Delivery of unrequested advertising (pop-up ads in particular),
– Harvesting private information
– Re-routing page requests to illegally claim commercial site referral fees
Spyware or Malware Can include:
– keystroke loggers
– denial-of-service (DoS) attack agents
A cookie is information sent by a server to a browser and then sent back to the server each time it accesses that server.
Typically this is used to authenticate or identify a registered user of a web site as part of their first login process or initial site registration without requiring them to sign in again every time they access that site.
Other uses are maintaining a "shopping basket" of goods selected for purchase during a session at a site, site personalization (presenting different pages to different users), and tracking a particular user's access to a site.