Ethereum interface security
It is illegal to issue virtual currency privately
According to Article 29 of the regulations of the people's Republic of China on the administration of RMB, no unit or indivial is allowed to print or sell token tickets to replace RMB in circulation on the market In addition, the "emergency notice of the State Council Office for rectifying unhealthy tendencies in the instry, the State Economic and Trade Commission and the people's Bank of China on prohibiting the issuance and use of various token certificates (cards)" also strictly prohibited similar issues 
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virtual currency refers to non real currency. Well known virtual currencies, such as online currency of Internet company, q-coin of Tencent company, q-point and voucher of Shanda company, micro currency launched by Sina (used for micro games, Sina reading, etc.), chivalrous Yuanbao (used for chivalrous road game), silver grain (used for bixue Qingtian game), and popular digital currencies in 2013 include bitcoin, Laite coin, infinite coin, quark coin, zeta coin, etc Barbecue coins, pennies (Internet), invisible gold bars, red coins, prime coins. At present, hundreds of digital currencies are issued all over the world. Popular in the circle & quot; The legend of "bitcoin, Wright silver, infinite copper, pennies aluminum"
market formation
the Internet has led to the emergence of a new market, which is a virtual market based on cyberspace. The Internet provides a lot of communication places for consumers, and also provides business market for enterprises. Enterprises must change from proct centered to service centered to customer centered. With the development of computer artificial intelligence technology and database technology, enterprises can conveniently collect customers' information, understand customers' needs in time, change business strategies and grasp economic arteries in real time
With the rapid development of computer and network communication technology, the application of Internet technology has graally penetrated into various fields of human activities, and the unlimited business opportunities that it contains make businesses turn their eyes to e-commerce. E-commerce is penetrating into all aspects of social and economic life at a speed that people can hardly imaginethe traditional finance is also closely watching this irresistible trend of global economic integration and networking. As a result, value-added services take art as the selling point and can be regarded as commodities; The sword in the game is not a brand-new financial services business philosophy - e-finance came into being
from the historical development process, to understand e-finance, we must start from the electronic finance and e-commerce. The so-called e-financialization means that financial enterprises adopt modern communication, computer, network and other information technology means in addition to Internet technology to improve the work efficiency of traditional financial service business, rece operating costs, realize the automation of financial business processing, informatization of financial enterprise management and scientific decision-making, and provide customers with faster and more convenient services, And then enhance the financial enterprise is the behavior of market competitive advantage
e-finance is a transcendence of financial electronization. Different from the electronic finance, the main technical basis of e-finance operation is the increasingly perfect Internet technology. Due to the characteristics of global connectivity, openness, quickness and low marginal cost of Internet technology, e-finance strengthens the restructuring and innovation of financial services business based on Internet technology, so that customers are free from the restrictions of business hours and places, and enjoy all kinds of high-quality and low-cost services provided by financial enterprises anytime and anywhere
with the development of Internet, the form of money is becoming more virtual, and there is an electronic money that only exists in the form of electronic signal
reference source: Network: virtual currency
Ethereum is an open source public blockchain platform with smart contract function. It provides decentralized virtual machine (Ethereum virtual machine) to process point-to-point contract through its special cryptocurrency ether (also known as "Ethereum")
The token on theblockchain is called ether, and the code is eth. It can be traded in many foreign exchange markets of cryptocurrency, and it is also the medium used to pay transaction fees and computing services on Ethereum
the concept of Ethereum was first proposed by vitalik buterin, a programmer, from 2013 to 2014, inspired by bitcoin, with the general meaning of "next generation cryptocurrency and decentralized application platform", and began to develop through ICO crowdfunding in 2014. As of February 2018, Ethernet is the second highest cryptocurrency in market value, second only to bitcoin
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Ethereum platform has no characteristics and value. Like programming languages, it's up to entrepreneurs and developers to decide what to use. However, it is clear that some application types benefit more from the functions of Ethereum than others. Ethereum is especially suitable for those applications that automatically interact directly between points or promote group coordination activities across networks
for example, coordinate the application of point-to-point market, or the automation of complex financial contracts. Bitcoin enables indivials to exchange money without the help of financial institutions, banks or governments. The impact of Ethereum may be more profound
in theory, any complex financial activities or transactions can be automatically and reliably carried out on Ethereum with coding. In addition to financial applications, any application scenario with high requirements for trust, security and persistence, such as asset registration, voting, management and Internet of things, will be affected by Ethereum platform on a large scale
1. Power consumption: 243w; Calculation force: 22.4m; Price: 1999 yuan; The number of eth g every 24 hours: 0.015; Revenue generated every 24 hours: 24.8 yuan; Expected payback time: 81.66 days
2. Power consumption of the whole machine: 159w; Calculation force: 24.3m; Price: 1599 yuan; Number of eth g every 24 hours: 0.017; Revenue generated every 24 hours: 27.9 yuan; Expected payback time: 57.31 days
3. Power consumption: 171w; Calculation force: 24.4m; Revenue generated every 24 hours: 27.87 yuan; Expected payback time: 71.73 days
4. Power consumption: 97W; Calculation force: 9.2; Price: 999 yuan; Number of eth g every 24 hours: 0.006; Revenue generated every 24 hours: 10.09 yuan; Expected payback time: 99.1 days
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mining machine risk
1. The problem of electricity charge
in order to make the graphics card full load for a long time, the power consumption will be quite high, and the electricity charge will be higher and higher. Many professional mines at home and abroad are operated in areas with extremely low electricity charges, such as hydropower stations, while more users can only mine at home or in ordinary mines, so the electricity charges are not cheap. Even in a certain residential area in Yunnan, there was a case of crazy mining, which led to a large area trip of the residential area, and the transformer was burned
2. Hardware expenditure
mining is actually a competition of performance and equipment. Some mining machines are composed of more such graphics card arrays. With dozens or even hundreds of graphics cards, the cost of hardware and other costs is very high, and there is a considerable expenditure in mining
3, currency security
the withdrawal of bitcoin requires hundreds of keys, and most people will record this long string of numbers on the computer, but the frequent problems such as hard disk damage will make the key permanently lost, which also leads to the loss of bitcoin
when installing Linux, if you have a network card, the installation program will prompt you to give the configuration parameters of TCP / IP network, such as the IP address of the local computer, the IP address of the default gateway, the IP address of DNS, etc, The installation program will automatically compile the network card (Linux system must first support) driver into the kernel. But we must understand the process of loading the network card driver, so we can easily operate when changing the network card and using multiple network cards in the future. The network card driver is loaded into the kernel as a mole, All the network card drivers supported by Linux are stored in the directory / lib / moles / (Linux version number) / net /, for example, the driver of Inter's 82559 series 10 / 100M self-adaptive boot network card is eepro100. O, 3Com's 3c509 isa network card is 3c509. O, dlink's PCI 10 network card is via Rhine. O, NE2000 compatible network card drivers are ne2k PCI. O and ne. O. after understanding these basic drivers, we can change the network card or add the network card by modifying the mole configuration file.
1. Modify the / etc / conf.moles file
this configuration file is an important parameter file to load the mole, Let's first look at a sample file
# / etc / conf.moles
alias eth0 eepro100
alias eth1 eepro100
this file is the content of conf.moles in a Linux system with two inter 82559 series network cards. The alias command indicates the name of the driver that the Ethernet port (such as eth0) has, If you use the command modprobe eth0, the system will automatically load eepro100. O into the kernel, Therefore, it is not necessary to use options in conf.moles to specify the IO address and interrupt number of the network card. However, corresponding to isa network card, you must specify the IO address or interrupt number of the hardware in conf.moles, as shown below, It shows a conf.moles file of NE isa NIC.
alias eth0 ne
Options ne IO = 0x300 IRQ = 5
after modifying the conf.moles file, you can use the command to load the mole, For example, to insert the second network card of inter:
? Insmod / lib / moles / 2.2.14/net/eepro100. O
in this way, the mole eepro100. O can be loaded at the Ethernet port, You can also use the command to view the currently loaded mole information:
[ root@ice /Etc] # lsmod
mole size used by
eepro100 15652 (autoclean)
the meaning of the returned result is that the currently loaded mole is eepro100, with 15652 bytes in size and two users, The method is to clear automatically.
2. Modify the / etc / lilo.conf file
in some relatively new Linux versions, because the operating system automatically detects all related hardware, there is no need to modify the / etc / lilo.conf file at this time, You can modify the lilo.conf file. Add the following command to the / etc / lilo.conf file:
append = & quot; ether=5,0x240,eth0 ether=7,0x300,eth1" <
the meaning of this command is that the IO address of eth0 is 0x240, the interrupt is 5, the IO address of eth1 is 0x300, and the interrupt is 7.
in fact, this statement comes from the parameter passed when the system boot image file,
Lilo: Linux ether = 5,0x240, eth0 ether = 7,0x300, eth1
this method can also make the Linux system configure two network cards, When using more than three network cards, you can follow the same method.
after configuring the network card, you should configure the TCP / IP parameters. In general, when installing the Linux system, you will be prompted to configure the network parameters, You can use the following commands:
? Ifconfig eth0 a.b.c.d netmask e.f.g.h
a.b.c.d is the IP address of eth0, and e.f.g.h is the netmask.
in fact, in Linux system, we can set multiple IP addresses for a network card, such as the following command:
? Ifconfig eth0: 1 202.112.11.218 netmask 255.255.192
then, Use the command "ifconfig - a" to see the interfaces of all network interfaces:
eth0 link encap:Ethernet HWaddr 00:90:27:58:AF:1A
inet addr:202.112.13.204 Bcast :202.112.13.255 M ask:255.255.255.192
UP BROADCAST RUNNING MULTICAST MTU:1500 M etric:1
RX packets:435510 errors :0 dropped:0 overruns :0 frame:2
TX packets:538988 e rrors:0 dropped :0 overruns:0 carrier :0
c ollisions:318683 txqueuelen :100
I nterrupt:10 Base address:0xc000
eth0:1 Link encap:Ethernet HWaddr 00:90:27:58:AF:1A
inet addr:202.112.11.218 Bcast :202.112.11.255 M ask:255.255.255.192
UP BROADCAST RUNNING MULTICAST MTU:1500 M etric:1
I nterrupt:10 Base address:0xc000 < br />
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask :255.0.0.0
UP LOOPBACK RUNNING MTU:3924 M etric:1
RX packets:2055 errors :0 dropped:0 overruns :0 frame:0
TX packets:2055 errors :0 dropped:0 overruns :0 carrier:0
c ollisions:0 txqueuelen : 0
we can see that there are three network interfaces, eth0, eth0:1, lo, Eth0 is the real Ethernet interface. Eth0:1 and eth0 are the same network card, but they are bound with another address. Lo is the sending address. Eth0 and eth0:1 can use IP addresses of different network segments, which is very useful when the same physical network segment uses different network addresses<
in addition, the network card has a mode of prosimc. In this mode, the network card will receive all the packets in the network. Some network monitoring tools under Linux, such as tcpmp and snort, all set the network card to hybrid mode.
the ifconfig command can change the IP address of the network card ring the running time, but if the system is restarted, the IP address of the network card will be changed, Linux still starts the network interface according to the original default settings. At this time, you can use netconfig or NETCONF command to reset the default network parameters. Netconfig command is to reconfigure the basic TCP / IP parameters, including whether to dynamically obtain IP address (dhcpd and BOOTP), IP address of network card, network mask, default gateway and preferred domain name server address. NETCONF command can configure all network parameters in detail, which is divided into three parts: client task, server task and other configuration. In the client configuration, it mainly includes the configuration of basic host (host name, valid domain name, network alias, IP address of corresponding network card, network mask, network device name, kernel driver of network device), DNS address configuration, default gateway address configuration, NIS address configuration, IPX interface configuration, PPP / slip configuration and so on. In the server configuration, it mainly includes the configuration of NFS, DNS, Apache webserver, samba and Wu ftpd. Among the other configuration options, one is about the host configuration in the / etc / hosts file, one is about the network configuration information in the / etc / networks file, and the last is about the configuration information using linuxconf
under the command of linuxconf, you can also configure the network information, but you can find that the linuxconf program calls NETCONF to configure the network
in addition, the system configuration files about the network are stored in the / etc / sysconfig / network scripts directory. Examples are as follows:
: & lt; br>& lt; br>
ifcfg-eth0 * ifdown post * ifup aliases * ifup PPP *
ifcfg-eth1 * ifdown PPP * ifup IPX * ifup routes *
ifcfg lo * ifdown sl * ifup PLIP * ifup sl *
ifdown @ ifup @ ifup post * network functions
ifcfg-eth0 is the configuration information of Ethernet port eth0, and its contents are as follows:
device = & quot; eth0" /* Specify the network device name * /
IPADDR = & quot; 202.112.13.204" /* Indicate the IP address of the network device * /
netmask = & quot; 255.255.255.192" /* Specify network mask * /
Network = 202.112.13.192 / * specify network address * /
broadcast = 202.112.13.255 / * specify broadcast address * /
onboot = & quot; yes" /* Indicates whether the network card is activated at system startup * /
bootproto = & quot; none" /* Indicates whether to use BOOTP protocol * /
therefore, we can also modify this file to change the network parameters under Linux[/ Size]
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1. The configuration file of Lilo
in Linux system, there is a system boot program, Lilo (Linux loadin), which can be used to realize the selective startup of multiple operating systems. Its configuration file is / etc / lilo.conf.in this configuration file, the configuration parameters of Lilo are mainly divided into two parts, One is the global configuration parameters, including setting the boot device and so on. The other is the local configuration parameters, including the configuration parameters of each boot image file. I will not describe each parameter in detail here, but only two important parameters: password and restricted option. The password option adds password protection to each boot image file.
as we all know, In Linux system, there is a single user mode. In this mode, the user logs in to the Linux system as a super user. By adding parameters (Linux single or Linux init 0) ring Lilo boot, people can directly enter the single user mode super user environment without password, This will be very dangerous. So the password configuration option is added in lilo.conf to add password protection to each image file.
you can use the password option in global mode (add the same password to all image files), or add a password to each indivial image file, You may find it troublesome to enter the password every time. You can use the restricted option, which enables Lilo to check the password only when the parameters (such as Linux single) are entered ring Linux startup. These two options can greatly increase the security of the system, It is recommended to set them in lilo.conf file.
since password is stored in plaintext in / etc / lilo.conf file, it is necessary to change the attribute of / etc / lilo.conf file to only root readable (0400).
in addition, in the early version of Lilo, there was a limitation that the boot sector must be stored in the first 1024 cylinder, which was broken in Lilo version 2.51, After downloading and decompressing the latest version, use the command make & quot; Note: physical security is the most basic security, even if the password protection is added in lilo.conf, if there is no password protection in lilo.conf
It is a kind of optical fiber Ethernet interface card, which transmits signals according to Ethernet communication protocol. It is generally connected with optical fiber Ethernet switch through optical cable
eth0 and eth1 are used to distinguish network card names. They have the same meaning as windows local connection 1 and local connection 2
the subnet card here is not a practical network interface, but it can flash in the system as a collection interface, such as eth0:1, eth1:2
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linux operating system embeds TCP / IP protocol stack, and protocol software has routing and forwarding function. Routing and forwarding rely on the installation of multiple network cards in the host as routers
when a network card receives a degree packet, the system kernel will query the routing table according to the destination IP address of the degree packet, then send the degree packet to another network card according to the query result, and finally send the degree packet through the network card. The process of host is the core function of router
routing function is realized by modifying Linux kernel parameters. The sysctl command is used to configure and display kernel parameters in the / proc / sys directory
for security reasons, Linux kernel forbids packet routing and forwarding by default. In Linux system, there are two ways to enable forwarding function: temporary and permanent