Paper Transistor

Paper transistor is one of the most important inventions in modern times. It revolutionized electronics and unlocked new and much, much smaller circuits. Portuguese researchers have produced the first discrete device paper based transistors. To be more precise, they have made the first field effect transistors (FET) with a paper interstrate layer. According to the research team, these new transistors offer the same level of performance as ’state-of-the-art oxide based thin film transistors (TFTs) produced on glass or crystalline silicon substrates.
A common paper sheet is used on both sides in the fabrication of the paper transistor. It means paper is used instead of silicon which was invented by a Portuguese team and is manufactured at ambient temperature. This way, the paper acts simultaneously as the electric insulator and as the substrate. Furthermore, electric characterization of devices showed that the hybrid FETs’ performance outpace those of amorphous silicon TFTs, and rival with the actual state of the art of oxide thin film transistors.
There is an increased interest in the use of biopolymers for low-cost electronic applications. Since cellulose is the Earth’s major biopolymer, some international teams have reported using paper as the physical support (substrate) of electronic devices but no one had used paper as an interstrate component of a FET.
The cellulose not only used as substrate but also act as electric insulator by fabricating the device on both sides of the paper. Add to that the paper transistor outperforms the amorphous silicon thin-film transistor used in modern LCD displays and is up to par with the very latest oxide thin-film transistors, which are still a rare sight.
Since paper is a flexible and a biomaterial it would open up new possibilities for bendable displays, bio-labeling, small and cheap displays that could be used for labeling of varies things and more. Our only concern so far is the degradability, i.e. the lifespan of displays made from paper.
These results suggest promising new disposable electronic devices electronics devices , like paper displays, smart labels, smart packaging, bio-applications and RFID tags.

Network Security: A Perspective

The technologies of computer security are based on logic. There is no universal standard notion of what secure behavior is. "Security" is a concept that is unique to each situation. Security is extraneous to the function of a computer application, rather than ancillary to it, thus security necessarily imposes restrictions on the application's behavior.

There are several approaches to security in computing; sometimes a combination of approaches is valid:

1. Trust all the software to abide by a security policy but the software is not trustworthy (this is computer insecurity).
2. Trust all the software to abide by a security policy and the software is validated as trustworthy (by tedious branch and path analysis for example).
3. Trust no software but enforce a security policy with mechanisms that are not trustworthy (again this is computer insecurity).
4. Trust no software but enforce a security policy with trustworthy mechanisms.

Many systems have unintentionally resulted in the first possibility. Since approach two is expensive and non-deterministic, its use is very limited. Approaches one and three lead to failure. Because approach number four is often based on hardware mechanisms and avoids abstractions and a multiplicity of degrees of freedom, it is more practical. Combinations of approaches two and four are often used in a layered architecture with thin layers of two and thick layers of four.

There are myriad strategies and techniques used to design security systems. There are few, if any, effective strategies to enhance security after design.

One technique enforces the principle of least privilege to great extent, where an entity has only the privileges that are needed for its function. That way even if an attacker gains access to one part of the system, fine-grained security ensures that it is just as difficult for them to access the rest.

Furthermore, by breaking the system up into smaller components, the complexity of individual components is reduced, opening up the possibility of using techniques such as automated theorem proving to prove the correctness of crucial software subsystems. This enables a closed form solution to security that works well when only a single well-characterized property can be isolated as critical, and that property is also assessable to math. Not surprisingly, it is impractical for generalized correctness, which probably cannot even be defined, much less proven. Where formal correctness proofs are not possible, rigorous use of code review and unit testing represent a best-effort approach to make modules secure.

The design should use "defense in depth", where more than one subsystem needs to be violated to compromise the integrity of the system and the information it holds. Defense in depth works when the breaching of one security measure does not provide a platform to facilitate subverting another. Also, the cascading principle acknowledges that several low hurdles do not make a high hurdle. So cascading several weak mechanisms does not provide the safety of a single stronger mechanism.

Subsystems should default to secure settings, and wherever possible should be designed to "fail secure" rather than "fail insecure" (see fail safe for the equivalent in safety engineering). Ideally, a secure system should require a deliberate, conscious, knowledgeable and free decision on the part of legitimate authorities in order to make it insecure.

In addition, security should not be an all or nothing issue. The designers and operators of systems should assume that security breaches are inevitable. Full audit trails should be kept of system activity, so that when a security breach occurs, the mechanism and extent of the breach can be determined. Storing audit trails remotely, where they can only be appended to, can keep intruders from covering their tracks. Finally, full disclosure helps to ensure that when bugs are found the "window of vulnerability" is kept as short as possible.

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