I want to introduct something about SF150 Fluorine
SF150 Fluorine Silicon Drilling Fluids Thinner (powder) In order to satisfy the need of drilling, we research and develop high-temperature drilling liquid thinner, which is convenient to carriage and usage. It is a kind of black mobile solid powder which has the excellent nature of lowing stick and function of fastening wall against collapse. It also has function of disperser, lubrication, and antifoaming to the drilling fluid system, and control hydrating shale and improve mudding function of drilling fluid. It’s maintaining time last long after dealing the mud. This kind of product is green and environmental Protection with non-toxic, and non-pollution. 1. Performance index Item Index Appearance Black mobile solid powder PH value 8~11 Wet value ?15 Stick falling rate % 90 ± 2 oC quantity addition 1% (percent by quality) ?80 120 ± 2 oC quantity ageing addition, 2.0% ( percent by quality) ?75 2. Application scope and method This product mainly apply to All kinds o
No security in this world is perfect. Security is always about the cost of implementing and enforcing the security versus the cost of the fraudster to break the security and the cost to be paid for the security breach. Depending on the type of the system, the cost may or may not be limited to just monetary cost but include the reputation damages, live lost but also national security. Certainly if human live and national security is concerned then the system cost may not be the most important consideration factor. However for many commercial smart card applications, it must be able to bring real benefits to all parties the application operator, cardholders and other service providers in the application. It must be able to help to make more money, lower cost and / or bring benefits to all parties in the application. Last but not least, smart card technology must be the most cost effective technology to be used.
Security in smart card applications
In any smart card application, a basic requirement is that it must be secured. The axiom for smart card application security is that the cost of enforcing the security must be much smaller than the effort to break the security and the cost to break the security must be higher than the potential rewards that can be obtained after breaking the security. In an efficiently designed smart cardapplication, the cost of the system implementation must be minimized but the security not compromised. A smart cardapplication is a distributed system. It compromises of a number of subsystems with each subsystem doing part of the system function. . The security of the system comprises of the front-end enforcement, frontend and back-end verification, backend audit and system fraud damage control. The system design always assumed a scenario of a fraud and how it can be controlled. Security must be addressed at the system level and not to be focused on just a small subsystem or component in the system. It can still make sense to use a lower cost card which is seemingly less secured in a smart card application but it does not mean that security will be compromised. Security can still be implemented in other subsystems so that the application remains secured and meanwhile lowering the entire system cost. To illustrate my argument, let's take a real application example of using the I2C free access memory card (e.g. 24C02) as a prepaid electricity meter card! This card is freely read and update and is therefore easily cloned. However a cloned card will not be accepted by the system. This is done as follows: The prepaid electricity meter is installed in the house and that it shall only accept one or a limited number of prepaid cards, using 24C02 free access memory card. A prepaid card is only acceptable to the meter if the card is authorized by the authority staff card for the first time, which his authorization system will ensure that the card is not being registered with another meter. The staff card can be inserted into the meter, followed by the prepaid card so that the card is registered by the meter. The card contains a serial number, a transaction counter and a stored value. These data is MAC-ed so that it cannot be tampered with being detected. During topping up of value into the meter, the meter shall first verify that the card serial number is registered in the meter and that the transaction counter is one higher than the previous transaction. Also the MAC indicates that the data has not been tampered. Then the transaction counter inside the meter is incremented and value is transferred to the meter. The fraudster will not know the MAC of the next transaction counter since he does not have the MAC key. He needs to pay for the topup before he becomes aware of the MAC. He cannot tamper with the stored value as it will be detected. A cloned card cannot be used as the meter expects the counter to be incremented in the card! This illustrate that even with a free access memory card, security can be achieved if the system security design is done correctly.
Is smart card really secure?
There has been some publicity in the smart card industry about how Mifare card can be cloned. People without good understanding about smart card application security design tend to focus only on the smart card and its algorithm. . Cryptographic algorithm in memory smart card such as Mifare certainly cannot be compared to CPU smart card. Competent smart card application designer using such type of card must implement other security measures in the card mapping design and in other subsystems to strengthen the application security. On the other hand, an incompetent designer, even if he uses the most secured card in the...(and so on) To get More information , you can visit some products about digital special multimeter, school supply counter, . The SF150 Fluorine Silicon Drilling Fluids Thinner (powder) products should be show more here!
The Importance of Good Caravan Repairs
14 years ago
No comments:
Post a Comment