User:RC4321/sandbox/Riskware

Secure transmission is the transfer of digital data such that the data is protected against anyone other than the sender and its intended recipient(s). To make sure of this, the data must be sent over a secure channel. This is done mainly through the process of encryption.

Without secure transmission, information is open to interception when sending sensitive messages, documents, and files over the Internet. Nowadays as more sensitive information is stored on computers and sent over the Internet or other communication means, ensuring information security and safety is vital.

The purpose of secure transmission is to ensure that data remains confidential, data cannot be modified, and data cannot be replayed.

History
Due to the increasing utility of digital communication, any type of digital communication needs to be secure. For this task, lots of algorithms for security have been implemented and used. The Data Encryption Standard (DES) became the federal standard for block symmetric encryption in 1977, succeeded by the Advanced Encryption Standard, or AES in 2003. Where DES used 64-bit blocks, AES uses 128-bit blocks. Doubling the block size increases the number of possible blocks by a factor of 264. With these developments, attackers have also come up with new ideas to penetrate the communication mediums such as truncated differentials, square attacks, interpolation attacks, and related-key attacks. Till now encryption has been the main tool used for the protection of data. With the increasing threat, stenography has also been used for security purposes.

How it works
When data is transmitted, it comes from a source device in the form of discrete signals or digital bit streams. These data streams/signals are placed over a communication medium, such as physical wires, wireless carriers, or optical fiber, for delivery to the destination/recipient device. Through many different means, (Ex: wiretapping, signal jamming) hackers can access a communication medium and eavesdrop or tamper with the data being sent. Secure transmission prevents this by modifying the data sent over a communication medium and/or preventing access to a communication medium.

Encryption Algorithms
Encryption algorithms mathematically scramble a message into a form readable only with a decryption key. There are two main types of encryption algorithms: symmetric key, and asymmetric key algorithms. Encryption is a powerful security mechanism because it can make decryption mathematically infeasible if you do not possess the decryption key. An analogy would be: mailing a document with a safe, only those who have the key can open the safe and access the contents inside. Some common types of encryption include RSA Data Security RC4, Data Encryption Standard (DES), Triple DES (3DES).

Stenography (w/ digital media)
Steganography is the practice of concealing a secret message within an ordinary message. Unlike encryption, where the existence of the encrypted message is visible to the whole world, steganography deals with composing hidden messages such that only the sender and receiver know that the message even exists. Steganography hides the existence of information exchange by embedding messages into non-suspicious digital media covers. These can be in forms such as text, images, audio, video, and etc. Digital stenography is common with file types .pdf, .jpg, .mp4, and .mp3.

Frequency-hopping Spread Spectrum (FHSS)
Frequency-hopping protects data by changing the frequency on which the data is sent over. It is achieved by dividing a large bandwidth into smaller channels that would fit the data. The data would then be sent pseudo-randomly into a channel. By sending the data into a pseudo-random channel, it is harder to intercept the data (it is harder to intercept something if you don't know where its going). Only the sender and intended recipients would know which pseudo-random channel the data is going to.

Direct Sequence Spread Spectrum (DSSS)
DSSS, the modern version of FHSS, spreads the information across a band in a different manner than FHSS. It does so by introducing pseudo-random noise into the signal to change its phase at any given time. This results in an output that closely resembles static noise and would appear as just that to others. But with a process called “de-spreading,” the original signal can be extracted from the noise as long as the pseudo-random sequence is known.