Bitcoin background running virus cracking

1. The concept of bitcoin was first proposed by Nakamoto in 2009. According to Nakamoto's idea, open source software was designed and released, and P2P network was built on it. Bitcoin is a kind of P2P digital currency. Point to point transmission means a decentralized payment system

unlike most currencies, bitcoin does not rely on specific currency institutions. It is generated by a large number of calculations based on specific algorithms. Bitcoin economy uses the distributed database composed of many nodes in the whole P2P network to confirm and record all transactions, and uses the design of cryptography to ensure the security of all aspects of currency circulation. The decentralized nature and algorithm of P2P can ensure that it is impossible to artificially manipulate the value of bitcoin through mass proction. The design based on cryptography can make bitcoin only be transferred or paid by the real owner. This also ensures the anonymity of money ownership and circulation transactions. The biggest difference between bitcoin and other virtual currencies is that the total amount of bitcoin is very limited and it has a strong scarcity. The monetary system used to have no more than 10.5 million in four years, after which the total number will be permanently limited to 21 million

bitcoin can be cashed and converted into the currency of most countries. Users can use bitcoin to buy some virtual items, such as clothes, hats and equipment in online games. As long as someone accepts it, they can also use bitcoin to buy real-life items< On February 26, 2014, Joe Manchin, a Democratic senator from West Virginia, issued an open letter to a number of regulatory authorities of the US federal government, hoping that relevant institutions would pay attention to the status quo of bitcoin's encouraging illegal activities and disrupting the financial order, and demanded that actions be taken as soon as possible to completely ban the electronic currency.

2. Because the cost of encryption is much less than decryption,
suppose that a supercomputer can violently try 1 billion passwords in one second by setting a password with numbers and uppercase and lowercase letters (a total of 62 characters), then:
it takes 1 second to crack 5-digit passwords (62 ^ 5 = 920 million),
it takes 62 seconds to crack 6-digit passwords,
it takes 1 hour to crack 7-digit passwords,
it takes 2.5 days to crack 8-digit passwords,
it takes half a year to crack 9-digit passwords,
it takes 100000 years to decipher 12 (more than the history of human civilization),
it takes 24.3 billion years to decipher 15 (more than the age of the universe)
the 15 bit password takes a few seconds to input more than the 5-bit password, but the decryption cost is almost impossible
even if the quantum computer can increase the cracking speed by 100 million times, it will only offset 27 bits of the 256 bit private key length of bitcoin (2 ^ 27 = 130 million). Even if extraterrestrials appear and the cracking speed is increased by 100 million times for several times in a row (each time the length of the private key is offset by 27 bits), bitcoin can simply upgrade the length of the private key to 512 bits.

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4. It's said that you can't restore without backup
if you can restore, who is afraid of the virus

5. Recently, many colleges and universities in China have been infected with blackmail software. Disk files will be encrypted by viruses. High intensity encryption algorithm is used for encryption, which is difficult to crack. Besides paying a high ransom, the attackers often have no other way to decrypt files. Only paying a high ransom can they decrypt and recover files, causing serious losses to learning materials and personal data. According to the network security agency, this is a virus attack launched by lawless elements using the "eternal blue" leaked from NSA hacker's weapon library“ "Eternal blue" will scan windows machines with open 445 file sharing port, without any user operation. As long as the machine is turned on and connected to the Internet, criminals can plant blackmail software, remote control Trojan horse, virtual currency mining machine and other malicious programs in computers and servers

to remind the majority of campus network users:
1. Install the latest security patch for the computer. Microsoft has released patch ms17-010 to fix the system vulnerability of "eternal blue" attack. Please install this security patch as soon as possible,
2. Close ports 445, 135, 137, 138 and 139, and turn off network sharing
3. Strengthen the awareness of network security: don't click unknown links, don't download unknown files, and don't open unknown e-mails
4. As soon as possible (in the future, regularly) back up the important files in your computer to the mobile hard disk and U disk, and save the disk offline after the backup
5. It is recommended that users who are still using Windows XP or windows 2003 should upgrade to Windows 7 / windows 10 or windows 2008 / 2012 / 2016 as soon as possible
6. Install genuine operating system, office software, etc.